WO2014092566A1 - Process and device for minimally invasive deep tissue probing - Google Patents
Process and device for minimally invasive deep tissue probing Download PDFInfo
- Publication number
- WO2014092566A1 WO2014092566A1 PCT/NL2013/050883 NL2013050883W WO2014092566A1 WO 2014092566 A1 WO2014092566 A1 WO 2014092566A1 NL 2013050883 W NL2013050883 W NL 2013050883W WO 2014092566 A1 WO2014092566 A1 WO 2014092566A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- cannula
- cannulae
- needle
- tissue
- tip
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims description 58
- 230000008569 process Effects 0.000 title claims description 52
- 230000008602 contraction Effects 0.000 claims abstract description 6
- 230000000149 penetrating effect Effects 0.000 claims abstract description 6
- 239000007924 injection Substances 0.000 claims description 53
- 238000002347 injection Methods 0.000 claims description 53
- 239000000463 material Substances 0.000 claims description 52
- 238000000576 coating method Methods 0.000 claims description 44
- 238000005530 etching Methods 0.000 claims description 43
- 239000011248 coating agent Substances 0.000 claims description 35
- 239000007788 liquid Substances 0.000 claims description 23
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 19
- 239000005350 fused silica glass Substances 0.000 claims description 16
- 230000001681 protective effect Effects 0.000 claims description 15
- 229960005486 vaccine Drugs 0.000 claims description 14
- 230000035515 penetration Effects 0.000 claims description 12
- 210000004027 cell Anatomy 0.000 claims description 11
- 239000012530 fluid Substances 0.000 claims description 10
- 230000000694 effects Effects 0.000 claims description 9
- 239000011521 glass Substances 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 8
- 239000011253 protective coating Substances 0.000 claims description 7
- 150000001875 compounds Chemical class 0.000 claims description 6
- 238000009792 diffusion process Methods 0.000 claims description 6
- 238000007654 immersion Methods 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 230000000638 stimulation Effects 0.000 claims description 5
- 150000002739 metals Chemical class 0.000 claims description 4
- 230000004936 stimulating effect Effects 0.000 claims description 4
- 238000011049 filling Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 210000000170 cell membrane Anatomy 0.000 claims description 2
- 230000003834 intracellular effect Effects 0.000 claims description 2
- 238000002493 microarray Methods 0.000 claims description 2
- 238000012546 transfer Methods 0.000 claims description 2
- 241000124008 Mammalia Species 0.000 claims 1
- 210000003491 skin Anatomy 0.000 description 48
- 210000001519 tissue Anatomy 0.000 description 33
- 238000003780 insertion Methods 0.000 description 28
- 230000037431 insertion Effects 0.000 description 28
- 238000000520 microinjection Methods 0.000 description 19
- 241000700159 Rattus Species 0.000 description 18
- 238000002649 immunization Methods 0.000 description 18
- 230000003053 immunization Effects 0.000 description 18
- 229940029583 inactivated polio vaccine Drugs 0.000 description 18
- 230000006378 damage Effects 0.000 description 10
- GNBHRKFJIUUOQI-UHFFFAOYSA-N fluorescein Chemical compound O1C(=O)C2=CC=CC=C2C21C1=CC=C(O)C=C1OC1=CC(O)=CC=C21 GNBHRKFJIUUOQI-UHFFFAOYSA-N 0.000 description 10
- 239000004642 Polyimide Substances 0.000 description 9
- 229920001721 polyimide Polymers 0.000 description 9
- 230000004044 response Effects 0.000 description 9
- LOKCTEFSRHRXRJ-UHFFFAOYSA-I dipotassium trisodium dihydrogen phosphate hydrogen phosphate dichloride Chemical compound P(=O)(O)(O)[O-].[K+].P(=O)(O)([O-])[O-].[Na+].[Na+].[Cl-].[K+].[Cl-].[Na+] LOKCTEFSRHRXRJ-UHFFFAOYSA-I 0.000 description 8
- 239000002953 phosphate buffered saline Substances 0.000 description 8
- 210000005013 brain tissue Anatomy 0.000 description 7
- 239000003921 oil Substances 0.000 description 7
- 210000002966 serum Anatomy 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 241001465754 Metazoa Species 0.000 description 6
- 239000000919 ceramic Substances 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 238000005070 sampling Methods 0.000 description 6
- 238000010790 dilution Methods 0.000 description 5
- 239000012895 dilution Substances 0.000 description 5
- 238000007918 intramuscular administration Methods 0.000 description 5
- 239000007927 intramuscular injection Substances 0.000 description 5
- 238000010255 intramuscular injection Methods 0.000 description 5
- 238000002255 vaccination Methods 0.000 description 5
- 241000991587 Enterovirus C Species 0.000 description 4
- 238000000339 bright-field microscopy Methods 0.000 description 4
- 229920002545 silicone oil Polymers 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 3
- 241000700605 Viruses Species 0.000 description 3
- 238000000799 fluorescence microscopy Methods 0.000 description 3
- 230000000670 limiting effect Effects 0.000 description 3
- 238000001000 micrograph Methods 0.000 description 3
- 239000013642 negative control Substances 0.000 description 3
- 230000003472 neutralizing effect Effects 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- UAIUNKRWKOVEES-UHFFFAOYSA-N 3,3',5,5'-tetramethylbenzidine Chemical compound CC1=C(N)C(C)=CC(C=2C=C(C)C(N)=C(C)C=2)=C1 UAIUNKRWKOVEES-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 208000032843 Hemorrhage Diseases 0.000 description 2
- 108010001336 Horseradish Peroxidase Proteins 0.000 description 2
- 241000709701 Human poliovirus 1 Species 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 241000274177 Juniperus sabina Species 0.000 description 2
- YQEZLKZALYSWHR-UHFFFAOYSA-N Ketamine Chemical compound C=1C=CC=C(Cl)C=1C1(NC)CCCCC1=O YQEZLKZALYSWHR-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000000427 antigen Substances 0.000 description 2
- 102000036639 antigens Human genes 0.000 description 2
- 108091007433 antigens Proteins 0.000 description 2
- 239000012131 assay buffer Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000000132 electrospray ionisation Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 230000028993 immune response Effects 0.000 description 2
- 238000001727 in vivo Methods 0.000 description 2
- 208000015181 infectious disease Diseases 0.000 description 2
- 229960003299 ketamine Drugs 0.000 description 2
- 230000005499 meniscus Effects 0.000 description 2
- 238000001690 micro-dialysis Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 235000010482 polyoxyethylene sorbitan monooleate Nutrition 0.000 description 2
- 229920000053 polysorbate 80 Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000013207 serial dilution Methods 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 238000007619 statistical method Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 210000000434 stratum corneum Anatomy 0.000 description 2
- 239000007929 subcutaneous injection Substances 0.000 description 2
- 238000010254 subcutaneous injection Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 239000001993 wax Substances 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- BPICBUSOMSTKRF-UHFFFAOYSA-N xylazine Chemical compound CC1=CC=CC(C)=C1NC1=NCCCS1 BPICBUSOMSTKRF-UHFFFAOYSA-N 0.000 description 2
- 229960001600 xylazine Drugs 0.000 description 2
- 241001116389 Aloe Species 0.000 description 1
- 241000283690 Bos taurus Species 0.000 description 1
- 238000002965 ELISA Methods 0.000 description 1
- 241000282412 Homo Species 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- 229920006328 Styrofoam Polymers 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 210000001015 abdomen Anatomy 0.000 description 1
- 230000003187 abdominal effect Effects 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 239000002671 adjuvant Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 235000011399 aloe vera Nutrition 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000000540 analysis of variance Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000000538 anti-polioviral effect Effects 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000004166 bioassay Methods 0.000 description 1
- 208000034158 bleeding Diseases 0.000 description 1
- 231100000319 bleeding Toxicity 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004556 brain Anatomy 0.000 description 1
- 238000004113 cell culture Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000013270 controlled release Methods 0.000 description 1
- 238000002316 cosmetic surgery Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 210000004207 dermis Anatomy 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000012377 drug delivery Methods 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 238000002674 endoscopic surgery Methods 0.000 description 1
- 239000004794 expanded polystyrene Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000002073 fluorescence micrograph Methods 0.000 description 1
- 239000007850 fluorescent dye Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000002458 infectious effect Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000007928 intraperitoneal injection Substances 0.000 description 1
- 210000003141 lower extremity Anatomy 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000002207 metabolite Substances 0.000 description 1
- 210000005036 nerve Anatomy 0.000 description 1
- 210000000944 nerve tissue Anatomy 0.000 description 1
- 210000002569 neuron Anatomy 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000000879 optical micrograph Methods 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229960001539 poliomyelitis vaccine Drugs 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 229940069575 rompun Drugs 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 230000036555 skin type Effects 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- BAZAXWOYCMUHIX-UHFFFAOYSA-M sodium perchlorate Chemical compound [Na+].[O-]Cl(=O)(=O)=O BAZAXWOYCMUHIX-UHFFFAOYSA-M 0.000 description 1
- 229910001488 sodium perchlorate Inorganic materials 0.000 description 1
- 238000000935 solvent evaporation Methods 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
- 239000008261 styrofoam Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 238000001356 surgical procedure Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
- 238000004670 tapping atomic force microscopy Methods 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 230000000451 tissue damage Effects 0.000 description 1
- 231100000827 tissue damage Toxicity 0.000 description 1
- 230000008733 trauma Effects 0.000 description 1
- 238000007492 two-way ANOVA Methods 0.000 description 1
- 210000003501 vero cell Anatomy 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
- QYEFBJRXKKSABU-UHFFFAOYSA-N xylazine hydrochloride Chemical compound Cl.CC1=CC=CC(C)=C1NC1=NCCCS1 QYEFBJRXKKSABU-UHFFFAOYSA-N 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/20—Surgical instruments, devices or methods, e.g. tourniquets for vaccinating or cleaning the skin previous to the vaccination
- A61B17/205—Vaccinating by means of needles or other puncturing devices
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/34—Trocars; Puncturing needles
- A61B17/3417—Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating
- A61B17/3421—Cannulas
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00526—Methods of manufacturing
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M25/00—Catheters; Hollow probes
- A61M25/0021—Catheters; Hollow probes characterised by the form of the tubing
- A61M2025/0042—Microcatheters, cannula or the like having outside diameters around 1 mm or less
Definitions
- the present invention relates to process and device for minimally invasively tissue probing, including sampling and/or injecting.
- the invention further relates to a process for shaping materials into hollow or solid microneedles for the sampling and/or injection, and for their use.
- the present invention further relates to the use of the solid devices for light guidance.
- Needle assemblies are commonly used to either inject substances into or extract substances out of human or animal tissue.
- needles presently employed are made from drawn stainless steel needles, such as for instance those disclosed in US-A-2, 814,296.
- a needle cannula is typically drawn from stainless steel through progressively smaller dies to reduce the diameter at the needle tip. The ratio between the outside diameter and the inside diameter is then a result of the wall thickness of the stainless tube drawn and the diameter to which it is drawn, but generally, is diminished over the length of the drawing process.
- Needle tips are then usually prepared by grinding or similar mechanical operations.
- the smallest commercially available needles, so called 34G thin-wall needles typically have an outer diameter (OD) of 200 pm, and an inner diameter (ID) of 100 pm, but have comparatively blunt tips.
- the commercially available needles with small tip diameters are generally prepared by heating a middle section of a glass cannula while pulling both ends of the cannula outwards.
- the thus drawn needles may than be cut, or may be etched to separate and the two needles.
- US-A-2007282265 discloses hollow needles made from ceramic, specifically zirconium oxide, having the outer diameter of 1 to 5 mm.
- the needles have a wall thickness of from 0.3 mm to 1 .8 mm, and are prepared by either covering a wire with ceramic powder, and then burning of the powder into a ceramic, or by mould injection and burning.
- the use of the above disclosed needles may lead to physical damage of the tissue during the entry and exit of a needle, and to haemorrhage, and thus to the destruction of vital cells in the path of the needle. This is in particular relevant for brain or nerve tissue probing, where even the smallest damage can be detrimental for nerve cell activity in the impacted areas. It may, depending on the damage exerted, even require opening of the area of the incision completely to repair damaged nerves or vessels.
- the present invention relates to an ultra- high aspect ratio needle cannula with pointed, distal end having an inner diameter in the range of from 0.5 to 250 pm, preferably 5 to 50 pm, an outer diameter in the range of from 50 to 2500 pm, and an aspect ratio of tip to length in the range of from 100 to 1x10 10 , for use in applications including deep tissue probing, painless injections, fluid dispensing, electrospray ionisation and light guiding.
- the present invention also relates to a process for the manufacture of a high aspect ratio needle cannula with pointed distal end deep tissue probing, fluid dispensing, electrospray ionisation and/or light guiding, comprising the steps of: (i) providing a needle cannula having a proximal end and a distal end and an oblong inside lumen there between;
- the process further comprises a step (v) at least partly coating an outside surface of the needle cannula with a coating material, prior to providing the etching liquid.
- the outside coating material may be chosen from any suitable material preferably a polymeric material; which improve mechanical properties of the cannula, such as polyimides.
- the coating material may preferably be applied in a range of 5 pm to 500 pm thickness.
- the coating preferably is inert to the etchant, however permits the etchant to slowly diffuse through the coating.
- the partial permeability of the coating may allow the needles to be etched through the coating, after which the etchant is sucked up between de fused silica and the coating by capillary force, thereby resulting in a particularly high aspect ratio. Without the coating the needle will primarily be etched where submerged in the etchant.
- Figure 1 depicts light microscopy images of a sharpened needle cannulae resulting from the process according to the invention.
- Figure 2 depicts micrographs of the formation of a needle cannula over time.
- Figure 3 depicts micrographs of rat brain tissue with injections according to the process and with a needle according to the invention, as well as comparative injection.
- Figure 4 discloses a batch of 81 fused silica capillaries mounted in a polyethylene holder and placed over a Teflon container with 49% HF. All needles are etched simultaneously by immersion in 49% HF. Immersion depth can be adjusted by the HF level in the container and the screw positions of the holder during mounting
- Figure 5 depicts a microneedle applicator was developed using an electromagnet (a) to insert a microneedle (c) into the skin at controlled speed.
- a micrometer actuator (b) is used to adjust the level of a supporting plateau (d) to ensure proper positioning and penetration depth of the microneedle.
- a graduated rail (e) can be used to tilt the entire applicator for angled insertion.
- the microneedle is connected to a syringe pump with a capillary (f) for vaccine delivery, g) Close-up of the supporting plateau with a through hole for the needle, h) Microneedle applicator injecting a vaccine into the skin of an anesthetized rat.
- Figure 6 discloses the determination of the depth of microneedle insertion. After hollow microneedles were pierced into fluorescein labeled human skin, one picture of the hollow microneedle was taken by using bright field microscopy (A), and another picture on the same position was taken by fluorescence microscopy (B). Subsequently, the bright field and fluorescence microscopy pictures were overlaid (C) from which the depth of microneedle insertion was measured and plotted as a function of the aimed insertion depth (D). Each point in panel D represents the average ( ⁇ SD) of three individual microneedle insertions.
- Figure 7 discloses the fluorescence visualization of fluorescein microinjections into ex vivo human skin. Control injections (fluorescein dispensed on top of the skin) result in solvent evaporation over time and, consequently, loss of fluorescence, while 300 pm deep injections show no leakage and loss off fluorescence, but prolonged fluorescence as well as diffusion into surrounding tissue.
- Figure 8 shows the serum IgG responses (mean ⁇ SEM) after immunization with PBS or inactivated poliovirus serotype 1 intramuscularly (i.m., 200 ⁇ _), intradermal ⁇ (i.d., 50 ⁇ _), or intradermal ⁇ via hollow microneedles with a microinjection of 9 ⁇ _ containing either 5 or 15 DU IPV.
- Figure 9 depicts serum polio-virus neutralizing (VN) antibodies responses after immunization with PBS or inactivated poliovirus serotype 1 intramuscularly (i.m.), intradermal ⁇ (i.d.), or intradermal ⁇ via hollow microneedles with a microinjection of 9 ⁇ _ containing either 5 or 15 DU IPV.
- VN serum polio-virus neutralizing
- the present invention encompasses a hollow needle shaped cannula with a distal end having preferably an atom sharp edge.
- the proximal end is typically comprised of a cylindrical or otherwise shaped tube.
- the inner diameter of the tube may be at least 0.5, such as at least 1 , or at least 10, or at least 20, or at least 50 ⁇ in diameter.
- the diameter, and hence lumen volume may be selected according to a particular application. For fluid injection or sampling of reasonable volumes, an inner diameter of at least 15 pm is preferred.
- the outer diameter is preferably at most 500 pm, more preferably at most 450 pm, yet more preferably at most 350 pm, again more preferably at most 300 pm, and yet more preferably at most 250 pm, and most preferably at most 200 pm,
- the outer surface of the cannula may taper over a length of hundreds of micrometres up to tens of millimetres to an atom sharp edged tip at the distal end.
- a generally constant inner diameter lumen may run along the length of the cannula from the proximal to the distal end allowing for the transport of e.g. liquids or gasses through the needle, avoiding for instance an undesired pressure drop.
- the length and angle of the tapered part of the needle can preferably be applied to a wide range, ranging from several pm lengths to several centimetres.
- the outer diameter of the proximal end can be chosen between 10 pm and several millimetres.
- the internal diameter can range from 0.1 pm to several millimetres. Even at relatively high inner and outer diameter, the subject invention provides for a very sharp edge at the tip, thereby diminishing negative effects during the deep tissue probing.
- the high aspect ratio of the needle and the atom sharp tip advantageously allow for easy penetration into a substrate with minimal damage to the substrate, for less invasive, local sampling or injection.
- the comparatively extremely high angle of the edge at the tip will prevent wetting of the sides of the needle when it is used as a nanoelectrospray ionisation source, and hence the subject invention also relates to this use.
- the extreme angle of the tip as expressed by the high aspect ratio, will also help preventing wetting of the outside of the canulla when fluids are dispensed from the cannula.
- the small diameter of the tip allow for the use of the needles with exceedingly small substrates such as single cells or specific skin or tissue regions.
- the lumen preferably has a constant internal diameter preventing clogging that is associated with conventional needles with a tapered lumen.
- the constant lumen further also advantageously improves capillary filling rates when sampling as the small diameter ensure high capillary suction along the entire length of the lumen.
- US-A-4, 469,554 discloses a process comprising at least partially immersing a cylindncally symmetric body in first liquid in order to etch the cylindrically symmetric body characterized in that a second liquid is located on top of the first liquid, said second liquid being substantially non-etching and substantially immiscible in the first liquid and the cylindrically symmetric body is a glass optical fiber consisting of at least 80 weight percent silicon dioxide.
- the material of the cannula is essentially an isotropic, etchable composition, preferably fused silica, glass and/or pure metals.
- the material subjected to etching should be an isotropic material with appropriate physical and chemical properties. Suitable examples are glass, and pure metals such titanium and/or copper.
- the glasses may have different physico-chemical properties, including of varying density, strength, optical transparency at a certain wavelength.
- suitable materials include ceramics, such as zirconia, titania and alumina.
- the ceramics may be conductive.
- Further suitable materials include polymeric materials, which may be etched with a suitable oxidative etchant or solvent.
- Alloys or similar component comprising different domains have proven less successful since e.g. in steel, specific crystalline domains are etched away faster than other, leading to a pitted surface and a structurally weaker composition.
- fused silica preferably with an polyimide coating, proved sufficiently strong to not break upon deep tissue insertion, nor in the retraction of the needle through repeated use.
- the substrates may be round, elliptical, rectangular, square, triangular, or of any other suitable shape.
- etchants may be used in the practice of the invention.
- the etchant should etch, or dissolve the capillary material being etched at a reasonable rate and approximately isotropically, although rotation of the material around the cylindrical axis might preferably increase the isotropic nature of the process.
- Typical etchants include aqueous HF for titanium, fused silica and various glasses including quartz glass; and aqueous sodium perchlorate for copper, or aqua regia for gold and platinum.
- Step (iii) is preferably performed by immersion of the distal end of the cannula in the etchant, i.e. the capillary tubing is preferably immersed into an etchant bath.
- the protective material used in the inert cavity should preferably not be miscible with the etching solution or etchant, or only to a very small extent to avoid the interior of the capillary to be in contact excessively with the etchant.
- the protective material should further be essentially chemically inert to the etchant. A limited amount of chemical attack may be tolerable, but materials that are prone to excessive attack should be avoided. Yet further, the protective material should preferably have a low vapour pressure to avoid evaporation of the liquid.
- Typical protective materials that are useful in the present process include silicon oils, hydrocarbon oils and waxes; and/or polyolefins.
- the protective materials preferably are liquid or can be liquefied such that they can be easily introduced into the capillary tubing prior to the etching process.
- the etchant Upon immersion, the etchant wets the surface of the capillary that is non-coated.
- the etching process will be determined by the mass transport of the etchant up the capillary.
- the lowest part of the immersed capillary is in close contact with unsaturated etchant, resulting in a faster etch.
- the etchant needs to diffuse further along the coating to reach the capillary material, resulting in a lower concentration of etchant, and hence slower etching.
- a particularly sharp edge is obtained at the tip of the capillary, leading to an atom sharp tip.
- etching through the coating appears to cause thinning of the entire length of the capillary as immersed or exposed to vapour.
- the protective material therefore preferably permits etchant vapours to diffuse through the material to the surface of the canulla.
- the combination of the direct contact at the tip, and the exposure to a lower concentration of the etchant in the non-immersed part through the protective material was found to contribute to the efficacy, and resulted in particularly high aspect ratios attainable by this method.
- the cannula according to the invention may advantageously be produced by etching sections of the capillary tubing with an etchant. Before etching, the inner surface of the lumen of the tubing is preferably coated, or completely filled with a liquid protective material such as for instance silicone oil, liquefied wax or a hydrocarbon oil.
- This step assures that the inner surface of the capillaries where in contact with the etchant is protected from the etchant during the subsequent etching processes, thus preserving the inner geometry.
- the protected capillary is then at least partially immersed into an etchant solution. If the etchant is not allowed to enter into the capillary, e.g. by a plug of oil, it is preferably not necessarily needed to coat the entire lumen.
- the outside of the capillary may advantageously be covered with a protective coating.
- This coating while not necessarily being inert under the conditions of the etching process, may serve as a barrier to the etchant to reduce the rate of etching on the outer surface of the tubing, thereby resulting in a higher cannula aspect.
- the outside coating is in particular relevant where a high aspect ratio cannula is required, where the tip is longer than the height of the meniscus that would be achieved in the case of a non-coated needle. Without a protective coating, only the meniscus will determine the shape and length of the tip, since the entire submersed capillary is etched away.
- Suitable coatings include thermoset flexible coatings, preferably a polyimide, a fuoropolymer and/or a dimethylsiloxane coating.
- the exterior coating is a flexible, protective coating that encloses the exterior of the capillary for substantially the entire length of the capillary.
- the protective coating is preferably applied to the capillary during manufacturing of the capillary.
- Typical coatings include the polyimide coatings applied for instance to gas chromatographic columns.
- the surface tension causes the etchant to partially displace the protective fluid, e.g. silicon oil, from inside the capillary.
- the capillary is immersed to a depth such that the level of the etchant/protective material interface inside the capillary is lower than the contact line between the etchant and capillary on the outside.
- the protective coating ensures that the walls above the actual tip stay intact, it should preferably allow a slow etching process that enables thinning of the walls along a certain length of the needles, thus decreasing the outer diameter, and increasing the aspect ratio.
- the etchant will remove a very small length of the capillary wall material from the inside out, as well as a small amount from the outside.
- the remaining portion of the capillary may be advantageously filled with protective material, such as inert material and/or a protective gas, which preserves the inner geometry during the etching process.
- the etching process is performed at suitable conditions. In the case of fused silica, this may conveniently be performed at room temperature.
- the etching rate can be estimated from measuring the end diameters of the etched section of the capillaries at different times. Accurate determination of the etching rate is useful to achieve high repeatability.
- the aspect ratio of cannula outer diameter and length is in the range of from preferably 1 : 1000, more preferably 1 : 100.000, yet more preferably 1x10 6 , yet more preferably 1x10 7 , yet more preferably 1x10 8 , again more preferably 1x10 9 , and most preferably 1x10 10 .
- the term "aspect ratio” herein denotes the aspect ratio of the width ⁇ N as measured at the tip of the pointed distal end to the length L measured from the tip to the beginning of a continuous contraction of the outer diameter of the cannula width; i.e. the length from the distal end of the tip to the proximal end of the tip i.e. the basis where the outer diameter starts to decrease.
- the thickness of the tip in the case of solid needle, or the wall thickness in the case of a hollow needle may be measured by any suitable method; where ultra high aspects are achieved, this may require the use of SEM or tapping atomic force microscopy.
- the ratio is in the range of from 1 10 to 900.000, Yet more preferably, the ratio is at least at or above 120, 130, 150, 180, 200, 300, 400, 500, 800, 1000, 1200. Yet more preferably, the ratio is at most at or below 850.000, 800.000, 750.000, 700.000, 500.000, 450.000, 300.000, 250.000, 150.000, 100.000, 500.000.
- the cannula according to the present invention furthermore may have a particularly sharp tip, i.e. a tip having a width between outer and inner wall of the cannula in the range of from one to several atom radii.
- the distal tip of the wall may have a wall thickness at the tip of from 1 10 to 1500 pm, more preferably of from 150 to 500 pm. This advantageously allows penetrating materials, such as tissue, with minimal damage, and/or without inflicting pain.
- the inner diameter of the cannula is preferably in the range of from 5 to 50 pm.
- the outer diameter of the cannula is preferably in the range of from 10 to 2500 pm, and preferably tapering to a very sharp tip, as set out below
- the subject invention further relates to a high aspect ratio needle cannula with pointed, tissue penetrating distal end for deep tissue probing, having an inner diameter in the range of from 5 to 50 pm, an outer diameter in the range of from 50 to 2500 pm.
- the thus obtained cannula may preferably be coated with conductive layers, releasable coatings, affinity coatings, e.g. antibodies, coatings that change the refractive index of the outer layer to keep light inside an optical conduit.
- Suitable coatings are those that make a needle visible with MRI or X-ray during surgery to allow very accurate positioning.
- overplating of the needle by a metal such as Nickel may not only allow to form a conductive coating, but at the same time may increase stability of the needle and/or the coating.
- coatings may be applied that strengthen the capillary, increasing its flexibility under pressure, and/or reducing the tendency of breaking off.
- the invention further relates to a device for deep tissue probing, comprising the needle according to the invention.
- the surface of the outside or inside of the needle wall can be modified. This may advantageously allow for tuning the rigidity of the needle, to provide, or enhance electrical conductivity allowing the needle to be used as an electrode, or to attract or release certain compounds.
- the invention further relates to a process for probing or injection into deep tissue, comprising a) providing a needle according to the invention, and b) inserting the needle into a tissue to inject material and/or extract material.
- the insertion may also be performed to selectively measure the release of certain metabolites, and/or to diagnose certain conditions, which may also be done in vivo, as well as for the stimulation of certain tissues.
- the present process further relates to a method of where the needle is coated with a conductive layer so an electrical response, e.g. in brain tissue can be measured directly, or after a certain compound has been injected with the needle into the brain tissue.
- the invention further relates to a multitude of cannulae assembled into a microarray of high aspect needles, and to devices comprising one or more cannulae according to the invention.
- the present invention further advantageously relates to a process for handling tissue material, comprising a) providing one or more cannulae according to the invention, and b) providing tissue material; and c) handling the tissue material using the one or more cannulae.
- the handling of tissue material comprises probing and/or injection of an injectable material into the tissue material.
- the present invention further advantageously relates to a process for recording and/or stimulating intracellular activity, comprising d) filling the cannulae with a conducting medium and connecting the cannula to a measurement apparatus; or using a conductive cannula connected to a measurement apparatus; e) penetrating a cell membrane, and f) recording and/or stimulating cell activity.
- the present invention also relates to a tool for supporting one or more of cannulae when subjected to the process according to the invention, comprising one or more flexible parts , each of which seals an area of the outside surface of each cannula from being in contact with the etching liquid or vapours during the execution of the etching step.
- the present invention also relates to the use of one or more hollow cannulae according to the invention, or obtainable according to the process according to invention as tissue probing device, nanoelectrospray ionisation source, painless injection needle, for the handling of tissue material, recording or stimulation of tissue or cells, for the ocular or single cell probing, including IVF, and/or for release of compounds into tissue.
- the present invention also relates to the use of one or more solid cannulae according to the invention, for light transfer and/or focussing, and/or light based stimulation or recording.
- the finished needle may further preferably be subjected to a secondary etch to make the material porous, resulting in cannulae useful as electrospray emitters.
- the present invention also relates to the use of a cannula for deposition, for use of the needle for removal of compounds (after injection, after dipping into a medium and from a fluid like air or gas); and as a non-clogging ESI emitter.
- applying a coating over the needle may allow for the formation of a membrane at the distal end of the tip, permitting the use of such a cannula for microdialysis and electro-microdialysis.
- Conventional intramuscular or subcutaneous injections of vaccines cause pain and stress, carry the risk of infection and need trained personnel.
- microneedles By only piercing the top layers of the skin, microneedles can be used for minimally invasive, pain free vaccine delivery to an immunologically active site.
- the subject invention also relates to a method for for painless intradermal vaccine delivery using the hollow microneedles according to the invention.
- one or more microneedles are preferably used in combination with an automated applicator, for instance advantageously electromagnetic applicator to control the insertion speed, depth, and or angle for painless intradermal vaccine delivery.
- a needle with a cylindrical inner geometry was fabricated by chemical etching in a diffusion-rate limited regime.
- the fabrication employed a polyimide coated, fused silica tubing usually employed for gas chromatography.
- the capillary was filled with silicon oil by capillary force.
- the capillary was then immersed into 49%wt. HF solution in a depth of several centimetres, for a period of several hours at room temperature, while capillary above the etchant was exposed to the gaseous atmosphere above the etchant.
- a needle according to example 1 was connected to a injection device, and a coloured fluid was injected into rat brain tissue.
- a commercially available and widely applied injection needle was employed.
- Fig. 3 showing a cut of brain tissue after three different injections into ventricles, and injecting Evans Blue to show the damage through the injection (track 2 as the result of a conventional small needle, tracks 1 and 3 by needles according to the subject invention).
- Hollow microneedles with an inner diameter of 20 pm were used to immunize rats with an inactivated poliovirus vaccine by an intradermal microinjection of 9 ⁇ _ at a depth of 300 pm and an insertion speed of 1 m/s.
- Intradermal microinjection induced comparable immune responses to conventional intramuscular injection, demonstrating the potential of the subject microneedles for pain free, minimally invasive intradermal vaccination.
- Polyimide coated fused silica capillaries (Polymicro, Phoenix AZ, USA, 375 pm outer diameter, 20 pm inner diameter) were wet etched into microneedles.
- the lumen of the capillaries was filled with silicone oil AK350 (Boom Chemicals, Meppel, the Netherlands) to protect the inside of the capillary from the etchant.
- AK350 Silicon Oil
- batches of up to 81 capillaries were mounted in a holder with one end suspended in 49% (w/w) HF, as shown in figure 4.
- the length of the capillary that is immersed in HF could be adjusted by the level of HF in the container as well as by the position of the screws of the holder during mounting.
- the shape of the microneedle tip was investigated as a function of etching time up to 30 hours.
- the microneedles chosen for the intradermal injections were etched for 4 hours.
- the sharp capillaries were glued into Luer adapters using medical grade glue (Loctite M-31 CL, Henkel, Dusseldorf, Germany). Luer adapters were acquired by removing the needle from Microlance® 26G hypodermic needles (BD, Franklin Lakes, NJ, USA).
- the polyimide coating was removed from the microneedles by submersion of the etched capillaries into hot sulfuric acid (96-98%, Boom chemicals, Meppel, the Netherlands) for 5 min at 200°C, and the silicone oil was removed by flushing the microneedles with acetone.
- an applicator for hollow microneedles was developed.
- the flexibility of the skin can hamper skin penetration and reduce the depth accuracy of injections.
- the insertion speed, insertion depth, and angle of insertion are important factors to overcome this and achieve successful depth controlled penetration and drug delivery.
- the applicator shown in Figure 5 used an electromagnet (a) to insert the microneedle mounted on the Luer connection (c) into the skin.
- the electromagnet was actuated using a controllable power source.
- Application of a variable current through the electromagnet allows for a tuned insertion speed from 1 -3 m/s.
- the controlled power supply regulates the wear time, to accurately and reproducibly control the time the microneedle is kept inside the skin.
- the skin is placed on a platform positioned below the injector (g).
- the penetration depth is controlled by a supporting plateau (d) that can be adjusted with a micrometer actuator (b).
- the position of the supporting plateau is adjusted so that the microneedle protrudes the desired distance through the hole in the plateau when the electromagnet is actuated.
- the injector is lowered so the supporting plateau rests on top of the skin.
- the needle is inserted into the skin at the desired speed and depth, as controlled by the current and plateau position.
- the entire applicator can be tilted along a graduated rail (e) for angled insertion (15°-90° relative to the skin). Insertion at a shallow angle can be used to insert a greater length of the needle into the skin, without penetration into deeper skin layers.
- the hollow microneedles were attached to a syringe pump that was equipped with a gas tight Luer lock 100 ⁇ _ syringe and connected to a fused silica capillary with a diameter of 100 pm (f) to allow tuning of the liquid delivery rate.
- phosphate buffered saline (PBS) (Braun, Melsungen, Germany, pH 7.4, 163.9 mM Na+, 140.3 mM CI-, 8.7 mM HPO42-, and H2PO4-).
- PBS phosphate buffered saline
- a microneedle was connected to the Luer connection on the microneedle applicator (figure 5c) and the micrometer actuator (figure 5d) was adjusted to a chosen depth up to 400 pm. In order to accurately set the insertion depth, the microneedle position was calibrated.
- the electromagnet was actuated and the microneedle was positioned to be flush with the plateau using the micrometer actuator (figure 5a). This was done by laser alignment, by which a laser was put perpendicular to the supporting plateau of the applicator (figure 5d). When a microneedle protrudes past the supporting plateau the laser light is scattered at the tip of the microneedle, therefore the needle was determined to be flushed with the plateau at the point where no light scattering was observed at the microneedle tip. After this calibration of the microneedle position, the microneedle actuator was adjusted to a depth of 100, 200, 300, or 400 pm, and was subsequently pierced into the fluorescently labeled human skin.
- microneedles were used to pierce the skin and each microneedle stayed in the skin for 5 s.
- the microneedles were analyzed by bright field microscopy and by fluorescence microscopy (Nikon Eclipse E600, mercury light source, GFP filter set) at 100x magnification and imaged with a 1 s exposure time.
- the bright field and fluorescence microscopy images were overlaid in ImageJ (available from rsbweb.nih.gov/ij/), and the insertion depth was expressed as the measured length between the tip of the microneedle and the part up to where the fluorescence was visible.
- a 10 pg/mL fluorescein solution in PBS was injected into human ex vivo skin at different depths (100-400 pm).
- the skin was stretched on Styrofoam covered with parafilm, and the injection depth was adjusted as described above.
- the microneedle was connected to a syringe pump with a flow rate of 2 pL/min to deliver 3 ⁇ _ of the fluorescein solution.
- 3 ⁇ _ of the fluorescein solution was dispensed on top of the skin.
- diffusion of the injected compound into surrounding tissue was assessed by imaging the fluorescence in the skin at several time points after injection.
- the fluorescence was imaged using a Microsoft Lifecam HD with a 480 ⁇ 5 nm light source (LED, Conrad) and a 520-540 nm band pass interference filter.
- Polystyrene 96 wells microtiter plates (Greiner Bio-One, Alphen a/d Rijn, the Netherlands) were coated overnight at 4°C with bovine anti-poliovirus type 1 serum (RIVM, Bilthoven, The Netherlands) in PBS pH 7.2 (Gibco from Invitrogen, Paisley, UK).
- RIVM bovine anti-poliovirus type 1 serum
- IPV vaccine type 1 100 ⁇ /well monovalent IPV vaccine type 1 (4.5 DU/well) diluted in assay buffer, PBS containing 0.5% (w/v) Protifar (Nutricia, Zoetermeer, the Netherlands) and 0.05% (v/v) Tween 80 (Merck, Darmstadt, Germany), was added. After incubation at 37°C for 2 hours, threefold dilutions of sera samples in assay buffer were added (100 ⁇ /well) and incubated at 37°C for 2 hours.
- Endpoint titers were determined by 4-parameter analysis using the Gen5TM 2.0 Data Analysis software (BioTek Instruments, Inc., Winooski, VT) and defined as the reciprocal of the serum dilution producing a signal identical to that of antibody-negative serum samples at the same dilution plus three times the standard deviation, as disclosed in Westdijk, J., et al. cited above, and Westdijk, J., et al., Antigen sparing with adjuvanted inactivated polio vaccine based on Sabin strains. Vaccine, 2013. 31 : p. 1298-1304.
- Virus neutralizing antibodies Virus neutralizing (VN) antibodies against poliovirus type 1 were measured as described in Westdijk, J., et al., above. In brief, the sera were inactivated at 56°C for 30 min prior to testing, of which 2 fold serial dilutions were made (21 to 224). These dilutions were incubated with 100 cell culture infectious dose 50% (CCID50) of wild type poliovirus type 1 (Mahoney) for 3 hours at 36°C and 5% C02, and the resulting mixtures were subsequently used to inoculate 1 ⁇ 104 Vero cells. Virus-neutralizing antibody titers were determined after 7 days by staining the cells with crystal violet and expressed as the last serial dilution with an intact monolayer.
- CCID50 cell culture infectious dose 50%
- Mehoney wild type poliovirus type 1
- Virus-neutralizing antibody titers were determined after 7 days by staining the cells with crystal violet and expressed as the last serial d
- microneedle geometry was observed to be dependent on etch time.
- Less than four hours of etching resulted in blunt needles with strong etching of the lumen of the capillary.
- Etch times between 4 and 22 hours resulted in increasingly long, thin needles of up to 4 cm. Longer etching resulted in fully dissolving extended portions of the capillary, leaving a short microneedle with an irreproducible tip shape.
- the observed lumen shapes are caused by displacement of the silicone oil.
- a small amount of HF is sucked into the lumen by capillary force, etching a short length from the inside. After 4 hours this portion is fully etched away, leaving only the part of the capillary that was protected from inside etching (figure 2c, h).
- the outer shape of the needle can be explained by the interaction between the HF and the polyimide coating.
- the coating is slightly permeable to HF. When HF permeates through the coating it slowly etches the fused silica and delaminates the coating and the fused silica. When the coating is separated from the capillary, HF is sucked in between by capillary force. This HF results in the strong etching that determines the final tip shape. As HF supply through the coating is small, mass transport by diffusion from the tip is limiting the etch rate, resulting in slower etching further away from the tip. This gradient in etch rate results in the sharp tip of the microneedle. Gluing the microneedles into Luer adapter resulted in needles that can be used and connected with the ease of conventional needles (figure 2).
- the relatively short needles obtained by 4 hours of etching were most suitable for injection into the skin because of their rigidity and robustness. While not suitable for injections into the skin, the extremely long needles can be useful for other applications.
- the ultra-high aspect ratio of these needles (4 cm long, 20 pm tip diameter, figure 2i) could be very useful for deep penetration into soft fragile tissue, e.g. for intracerebral injections.
- Microneedle applicators are preferably employed or controlled and reproducible microneedle application and reduce the required insertion forces to pierce the stratum corneum for both solid and hollow microneedles.
- microneedle applicator advantageously used in this work was particularly useful for in- and ex-vivo microinjections with easily adjustable insertion speed, depth, angle, and flow rate. Robust performance was observed, i.e. at an insertion speed of 1 m/s no damage of the needles was observed.
- the present sytem comrpsiing the needle sadn applicator was found to to aloe higher flow rates as compared to those disclosed for other systems in the literature, which may have been limited by the maximum applicable pressure in systems using common flexible tubing and different pump types.
- the full tunability of the device was found very valuable in a research setting, where varying injections into different skin types and layers are required. Whilst completely compatible with use for intradermal microinjections in in vivo arms of humans, the freestanding setup of the device was also particularly suitable for use in animal studies, as it allows for easy handling of the animals.
- microneedle applicator for routine use may not need the tunability and flexibility offered by the applicator embodiment disclosed above. Hene, the principles may also be applied in a simplified, hence cheaper, handheld device suitable for large scale immunizations. Determination of microneedle insertion depth
- FIG 7a-c depicts micrographs of microneedles after instertion into fluorescently labeled ex vivo human skin with a velocity of 1 m/s. The distance between the fluorescent dye transferred from the skin and the tip of the needle was used to measure penetration depth.
- Intradermal injections where visualized by injection of 3 ⁇ _ fluorescein at a flow speed of 2 L/min into ex vivo human skin. Successful injections were observed at all the injection depths that were tested (100-400 pm). As depicted in figure 7, fluorescence from the injected fluorescein was observed below the surface of the skin. No leakage was observed and diffusion into surrounding tissue was indicated by an increasing area of low fluorescence around the injection site. The negative control of fluorescein dispensed on top of the skin showed fast evaporation of the solvent, causing rapid loss of fluorescence intensity. No significant difference in fluorescence intensity between penetration depths from 100-400 pm was observed in the skin (data not shown).
- Intradermal microinjection of IPV showed comparable IgG responses to conventional intramuscular injections or intradermal injections. Furthermore, immunization with IPV by microinjection led to the induction of VN antibodies. Etched hollow microneedles can offer pain free, minimally invasive intradermal injections for vaccine delivery.
Abstract
The present invention relates to an ultra- high aspect ratio needle cannula with pointed, tissue penetrating distal end for deep tissue probing, having an inner diameter in the range of from 5 to 50 pm, an outer diameter in the range of from 50 to 2500 pm, and an aspect ratio of the width 1/1/ measured at the tip of the pointed distal end to the length L measured from the tip to the beginning of a continuous contraction of the outer diameter of the cannula, in the range of from 1 : 100 to 1 : 1x1010
Description
PROCESS AND DEVICE FOR MINIMALLY INVASIVE DEEP TISSUE PROBING
FIELD OF THE INVENTION
The present invention relates to process and device for minimally invasively tissue probing, including sampling and/or injecting. The invention further relates to a process for shaping materials into hollow or solid microneedles for the sampling and/or injection, and for their use. The present invention further relates to the use of the solid devices for light guidance.
BACKGROUND OF THE INVENTION
In recent years, many operations in sensitive tissues and organs, such as for instance deep brain tissue are performed through stereotactic endoscopic surgery, using probing and injection instruments of ever-decreasing size. Needle assemblies are commonly used to either inject substances into or extract substances out of human or animal tissue.
However, most needles presently employed are made from drawn stainless steel needles, such as for instance those disclosed in US-A-2, 814,296. A needle cannula is typically drawn from stainless steel through progressively smaller dies to reduce the diameter at the needle tip. The ratio between the outside diameter and the inside diameter is then a result of the wall thickness of the stainless tube drawn and the diameter to which it is drawn, but generally, is diminished over the length of the drawing process. Needle tips are then usually prepared by grinding or similar mechanical operations. The smallest commercially available needles, so called 34G thin-wall needles, typically have an outer diameter (OD) of 200 pm, and an inner diameter (ID) of 100 pm, but have comparatively blunt tips.
The commercially available needles with small tip diameters are generally prepared by heating a middle section of a glass cannula while pulling both ends of the cannula outwards. The thus drawn needles may than be cut, or may be etched to separate and the two needles.
While this can lead to sub micrometer tip diameter, the inner and outer diameter of the cannulae usually rapidly decreases in the direction of the tip, resulting in a high pressure drop over the needle tip in use. The funnel shaped lumen is also prone to clogging. The volume of the lumen thus created is also very high compared to the tip dimensions.
US-A-2007282265 discloses hollow needles made from ceramic, specifically zirconium oxide, having the outer diameter of 1 to 5 mm. The needles have a wall thickness of from 0.3 mm to 1 .8 mm, and are prepared by either covering a wire with ceramic powder, and then burning of the powder into a ceramic, or by mould injection and burning. While this process allows preparation of comparatively tough needles that can be employed where equally dimensioned steel needles would buckle under the pressure during injection into tougher tissues, the thus obtained needles still have the same, large dimensions, resulting in tissue damage. Yet further, the process is tedious and complex.
The use of the above disclosed needles may lead to physical damage of the tissue during the entry and exit of a needle, and to haemorrhage, and thus to the destruction of vital cells in the path of the needle. This is in particular relevant for brain or nerve tissue probing, where even the smallest damage can be detrimental for nerve cell activity in the impacted areas. It may, depending on the damage exerted, even require opening of the area of the incision completely to repair damaged nerves or vessels.
Further issues with existing needles include that due to the changing diameter of the lumen of the needle due to the drawing process, or due to imperfections on the surface of a ceramic needle, pressure may build up during injections, clogging of the cannula may occur, and a less favourable shape for sampling is obtained. Yet further, as conventional small needles as described herein above are sharpened by bevelling the tip, this limits the depth accuracy when probing.
Accordingly, there is a need for deep tissue probes, whose use results in significantly less trauma, as well as a suitable versatile process for their manufacture.
SUMMARY OF THE INVENTION
Accordingly, in a first aspect, the present invention relates to an ultra- high aspect ratio needle cannula with pointed, distal end having an inner diameter in the range of from 0.5 to 250 pm, preferably 5 to 50 pm, an outer diameter in the range of from 50 to 2500 pm, and an aspect ratio of tip to length in the range of from 100 to 1x1010, for use in applications including deep tissue probing, painless injections, fluid dispensing, electrospray ionisation and light guiding.
In a second aspect, the present invention also relates to a process for the manufacture of a high aspect ratio needle cannula with pointed distal end deep tissue probing, fluid dispensing, electrospray ionisation and/or light guiding, comprising the
steps of: (i) providing a needle cannula having a proximal end and a distal end and an oblong inside lumen there between;
(ii) at least partly covering the outer surface of the cannula with a protective coating which is inert to the etching liquid, such that the coating prevents the etchant from directly contacting the outer surface of the cannula;
(iii) at least partly preventing the etchant from entering the lumen or etching the inner surface, preferably by coating an inside surface of the lumen with a protective material, which is inert to the etching liquid, or by preventing the etchant liquid from entering the lumen, such as by applying a gas flow with sufficiently high pressure to the lumen, and (iv) contacting the front end of the cannula with an etching liquid to obtain a needle cannula with a pointed distal end. Preferably the process further comprises a step (v) at least partly coating an outside surface of the needle cannula with a coating material, prior to providing the etching liquid. The outside coating material may be chosen from any suitable material preferably a polymeric material; which improve mechanical properties of the cannula, such as polyimides. The coating material may preferably be applied in a range of 5 pm to 500 pm thickness.
The coating preferably is inert to the etchant, however permits the etchant to slowly diffuse through the coating. Without wishing to be bound to any particular theory, it is believed that the partial permeability of the coating may allow the needles to be etched through the coating, after which the etchant is sucked up between de fused silica and the coating by capillary force, thereby resulting in a particularly high aspect ratio. Without the coating the needle will primarily be etched where submerged in the etchant.
Description of the Figures
Figure 1 : Figure 1 depicts light microscopy images of a sharpened needle cannulae resulting from the process according to the invention.
Figure 2: Figure 2 depicts micrographs of the formation of a needle cannula over time.
Figure 3: Figure 3 depicts micrographs of rat brain tissue with injections according to the process and with a needle according to the invention, as well as comparative injection.
Figure 4: Figure 4 discloses a batch of 81 fused silica capillaries mounted in a polyethylene holder and placed over a Teflon container with 49% HF. All needles are etched simultaneously by immersion in 49% HF. Immersion depth can be adjusted by the HF level in the container and the screw positions of the holder during mounting
Figure 5: Figure 5 depicts a microneedle applicator was developed using an electromagnet (a) to insert a microneedle (c) into the skin at controlled speed. A micrometer actuator (b) is used to adjust the level of a supporting plateau (d) to ensure proper positioning and penetration depth of the microneedle. A graduated rail (e) can be used to tilt the entire applicator for angled insertion. The microneedle is connected to a syringe pump with a capillary (f) for vaccine delivery, g) Close-up of the supporting plateau with a through hole for the needle, h) Microneedle applicator injecting a vaccine into the skin of an anesthetized rat.
Figure 6: Figure 6 discloses the determination of the depth of microneedle insertion. After hollow microneedles were pierced into fluorescein labeled human skin, one picture of the hollow microneedle was taken by using bright field microscopy (A), and another picture on the same position was taken by fluorescence microscopy (B). Subsequently, the bright field and fluorescence microscopy pictures were overlaid (C) from which the depth of microneedle insertion was measured and plotted as a function of the aimed insertion depth (D). Each point in panel D represents the average (± SD) of three individual microneedle insertions.
Figure 7: Figure 7 discloses the fluorescence visualization of fluorescein microinjections into ex vivo human skin. Control injections (fluorescein dispensed on top of the skin) result in solvent evaporation over time and, consequently, loss of fluorescence, while 300 pm deep injections show no leakage and loss off fluorescence, but prolonged fluorescence as well as diffusion into surrounding tissue.
Figure 8: Figure 8 shows the serum IgG responses (mean±SEM) after immunization with PBS or inactivated poliovirus serotype 1 intramuscularly (i.m., 200 μΙ_), intradermal^ (i.d., 50 μΙ_), or intradermal^ via hollow microneedles with a microinjection of 9 μΙ_ containing either 5 or 15 DU IPV.
Figure 9: Figure 9 depicts serum polio-virus neutralizing (VN) antibodies responses after immunization with PBS or inactivated poliovirus serotype 1 intramuscularly (i.m.), intradermal^ (i.d.), or intradermal^ via hollow microneedles with a microinjection of 9 μΙ_ containing either 5 or 15 DU IPV.
The present invention encompasses a hollow needle shaped cannula with a distal end having preferably an atom sharp edge.
The proximal end is typically comprised of a cylindrical or otherwise shaped tube. The inner diameter of the tube may be at least 0.5, such as at least 1 , or at least 10, or at least 20, or at least 50 μηι in diameter. The diameter, and hence lumen volume may
be selected according to a particular application. For fluid injection or sampling of reasonable volumes, an inner diameter of at least 15 pm is preferred.
The outer diameter is preferably at most 500 pm, more preferably at most 450 pm, yet more preferably at most 350 pm, again more preferably at most 300 pm, and yet more preferably at most 250 pm, and most preferably at most 200 pm,
Depending on the process, the outer surface of the cannula may taper over a length of hundreds of micrometres up to tens of millimetres to an atom sharp edged tip at the distal end. Advantageously, a generally constant inner diameter lumen may run along the length of the cannula from the proximal to the distal end allowing for the transport of e.g. liquids or gasses through the needle, avoiding for instance an undesired pressure drop.
The length and angle of the tapered part of the needle can preferably be applied to a wide range, ranging from several pm lengths to several centimetres.
Preferably the outer diameter of the proximal end can be chosen between 10 pm and several millimetres. The internal diameter can range from 0.1 pm to several millimetres. Even at relatively high inner and outer diameter, the subject invention provides for a very sharp edge at the tip, thereby diminishing negative effects during the deep tissue probing.
The high aspect ratio of the needle and the atom sharp tip advantageously allow for easy penetration into a substrate with minimal damage to the substrate, for less invasive, local sampling or injection. Again further, the comparatively extremely high angle of the edge at the tip will prevent wetting of the sides of the needle when it is used as a nanoelectrospray ionisation source, and hence the subject invention also relates to this use. The extreme angle of the tip, as expressed by the high aspect ratio, will also help preventing wetting of the outside of the canulla when fluids are dispensed from the cannula.
Furthermore, the small diameter of the tip allow for the use of the needles with exceedingly small substrates such as single cells or specific skin or tissue regions.
The lack of a high angle bevelled tip also increases the depth accurately allowing for accurate injection to a certain depth, while also preventing leakage in shallow injections. Yet further, the lumen preferably has a constant internal diameter preventing clogging that is associated with conventional needles with a tapered lumen. The constant lumen further also advantageously improves capillary filling rates when sampling as the small diameter ensure high capillary suction along the entire length of
the lumen.
US-A-4, 469,554 discloses a process comprising at least partially immersing a cylindncally symmetric body in first liquid in order to etch the cylindrically symmetric body characterized in that a second liquid is located on top of the first liquid, said second liquid being substantially non-etching and substantially immiscible in the first liquid and the cylindrically symmetric body is a glass optical fiber consisting of at least 80 weight percent silicon dioxide.
The publication entitled "Fabrication Process of Microsurgical Tools for Single- Cell Trapping and Intracytoplasmic Injection", JMEMS, p.940-945, Vol.13, No. 6, Dec. 2004, discloses the preparation of single-cell trappers and microinjectors from fused silica capillaries via a diffusion limited etching method based on US-A-4, 469, 554, and their use as tools for single cell manipulations. However, in this process, the entire length of the tip is immersed in the etching liquid, thereby limiting the available aspect ratio.
Preferably the material of the cannula is essentially an isotropic, etchable composition, preferably fused silica, glass and/or pure metals.
Generally, the material subjected to etching should be an isotropic material with appropriate physical and chemical properties. Suitable examples are glass, and pure metals such titanium and/or copper. The glasses may have different physico-chemical properties, including of varying density, strength, optical transparency at a certain wavelength.
Other suitable materials include ceramics, such as zirconia, titania and alumina. The ceramics may be conductive. Further suitable materials include polymeric materials, which may be etched with a suitable oxidative etchant or solvent.
Alloys or similar component comprising different domains have proven less successful since e.g. in steel, specific crystalline domains are etched away faster than other, leading to a pitted surface and a structurally weaker composition. Applicants found that for instance fused silica, preferably with an polyimide coating, proved sufficiently strong to not break upon deep tissue insertion, nor in the retraction of the needle through repeated use.
The substrates may be round, elliptical, rectangular, square, triangular, or of any other suitable shape.
In the process according to the subject invention, various etchants may be used in the practice of the invention. Generally, the etchant should etch, or dissolve the
capillary material being etched at a reasonable rate and approximately isotropically, although rotation of the material around the cylindrical axis might preferably increase the isotropic nature of the process.
Typical etchants include aqueous HF for titanium, fused silica and various glasses including quartz glass; and aqueous sodium perchlorate for copper, or aqua regia for gold and platinum.
Step (iii) is preferably performed by immersion of the distal end of the cannula in the etchant, i.e. the capillary tubing is preferably immersed into an etchant bath.
The protective material used in the inert cavity should preferably not be miscible with the etching solution or etchant, or only to a very small extent to avoid the interior of the capillary to be in contact excessively with the etchant.
The protective material should further be essentially chemically inert to the etchant. A limited amount of chemical attack may be tolerable, but materials that are prone to excessive attack should be avoided. Yet further, the protective material should preferably have a low vapour pressure to avoid evaporation of the liquid.
Typical protective materials that are useful in the present process include silicon oils, hydrocarbon oils and waxes; and/or polyolefins. The protective materials preferably are liquid or can be liquefied such that they can be easily introduced into the capillary tubing prior to the etching process.
Upon immersion, the etchant wets the surface of the capillary that is non-coated.
Where the capillary is provided with a coating, inside the coating, the etching process will be determined by the mass transport of the etchant up the capillary.
Without wishing to be bound to any particular theory, the lowest part of the immersed capillary is in close contact with unsaturated etchant, resulting in a faster etch. Further up the capillary, the etchant needs to diffuse further along the coating to reach the capillary material, resulting in a lower concentration of etchant, and hence slower etching. As a result, a particularly sharp edge is obtained at the tip of the capillary, leading to an atom sharp tip. Furthermore, etching through the coating appears to cause thinning of the entire length of the capillary as immersed or exposed to vapour. The protective material therefore preferably permits etchant vapours to diffuse through the material to the surface of the canulla. The combination of the direct contact at the tip, and the exposure to a lower concentration of the etchant in the non-immersed part through the protective material was found to contribute to the efficacy, and resulted in particularly high aspect ratios attainable by this method.
The cannula according to the invention may advantageously be produced by etching sections of the capillary tubing with an etchant. Before etching, the inner surface of the lumen of the tubing is preferably coated, or completely filled with a liquid protective material such as for instance silicone oil, liquefied wax or a hydrocarbon oil. This may conveniently be done by immersing the same end into the solvent and allowing the capillary forces to draw the oil inside, preferably assisted by applying a vacuum to the proximal end if the amount and/or penetration or coating depth of protective material is more than that achieved through capillary forces. This step assures that the inner surface of the capillaries where in contact with the etchant is protected from the etchant during the subsequent etching processes, thus preserving the inner geometry. The protected capillary is then at least partially immersed into an etchant solution. If the etchant is not allowed to enter into the capillary, e.g. by a plug of oil, it is preferably not necessarily needed to coat the entire lumen.
The outside of the capillary may advantageously be covered with a protective coating. This coating, while not necessarily being inert under the conditions of the etching process, may serve as a barrier to the etchant to reduce the rate of etching on the outer surface of the tubing, thereby resulting in a higher cannula aspect.
The outside coating is in particular relevant where a high aspect ratio cannula is required, where the tip is longer than the height of the meniscus that would be achieved in the case of a non-coated needle. Without a protective coating, only the meniscus will determine the shape and length of the tip, since the entire submersed capillary is etched away.
Suitable coatings include thermoset flexible coatings, preferably a polyimide, a fuoropolymer and/or a dimethylsiloxane coating. Preferably the exterior coating is a flexible, protective coating that encloses the exterior of the capillary for substantially the entire length of the capillary.
The protective coating is preferably applied to the capillary during manufacturing of the capillary. Typical coatings include the polyimide coatings applied for instance to gas chromatographic columns.
Without wishing to be bound to any particular theory, it is believed that the surface tension causes the etchant to partially displace the protective fluid, e.g. silicon oil, from inside the capillary. In order to ensure the fabrication of the sharp tip, the capillary is immersed to a depth such that the level of the etchant/protective material interface inside the capillary is lower than the contact line between the etchant and
capillary on the outside.
While the protective coating ensures that the walls above the actual tip stay intact, it should preferably allow a slow etching process that enables thinning of the walls along a certain length of the needles, thus decreasing the outer diameter, and increasing the aspect ratio.
As a result, the etchant will remove a very small length of the capillary wall material from the inside out, as well as a small amount from the outside. The remaining portion of the capillary may be advantageously filled with protective material, such as inert material and/or a protective gas, which preserves the inner geometry during the etching process.
The etching process is performed at suitable conditions. In the case of fused silica, this may conveniently be performed at room temperature. The etching rate can be estimated from measuring the end diameters of the etched section of the capillaries at different times. Accurate determination of the etching rate is useful to achieve high repeatability.
Preferably, the aspect ratio of cannula outer diameter and length is in the range of from preferably 1 : 1000, more preferably 1 : 100.000, yet more preferably 1x106, yet more preferably 1x107, yet more preferably 1x108, again more preferably 1x109, and most preferably 1x1010.
The term "aspect ratio" herein denotes the aspect ratio of the width \N as measured at the tip of the pointed distal end to the length L measured from the tip to the beginning of a continuous contraction of the outer diameter of the cannula width; i.e. the length from the distal end of the tip to the proximal end of the tip i.e. the basis where the outer diameter starts to decrease. The thickness of the tip in the case of solid needle, or the wall thickness in the case of a hollow needle may be measured by any suitable method; where ultra high aspects are achieved, this may require the use of SEM or tapping atomic force microscopy.
Preferably the ratio is in the range of from 1 10 to 900.000, Yet more preferably, the ratio is at least at or above 120, 130, 150, 180, 200, 300, 400, 500, 800, 1000, 1200. Yet more preferably, the ratio is at most at or below 850.000, 800.000, 750.000, 700.000, 500.000, 450.000, 300.000, 250.000, 150.000, 100.000, 500.000.
The cannula according to the present invention furthermore may have a particularly sharp tip, i.e. a tip having a width between outer and inner wall of the cannula in the range of from one to several atom radii. Accordingly, the distal tip of the
wall may have a wall thickness at the tip of from 1 10 to 1500 pm, more preferably of from 150 to 500 pm. This advantageously allows penetrating materials, such as tissue, with minimal damage, and/or without inflicting pain.
Preferably, the inner diameter of the cannula is preferably in the range of from 5 to 50 pm. Furthermore, the outer diameter of the cannula is preferably in the range of from 10 to 2500 pm, and preferably tapering to a very sharp tip, as set out below
The subject invention further relates to a high aspect ratio needle cannula with pointed, tissue penetrating distal end for deep tissue probing, having an inner diameter in the range of from 5 to 50 pm, an outer diameter in the range of from 50 to 2500 pm.
The thus obtained cannula may preferably be coated with conductive layers, releasable coatings, affinity coatings, e.g. antibodies, coatings that change the refractive index of the outer layer to keep light inside an optical conduit. Suitable coatings are those that make a needle visible with MRI or X-ray during surgery to allow very accurate positioning. Furthermore, overplating of the needle by a metal such as Nickel may not only allow to form a conductive coating, but at the same time may increase stability of the needle and/or the coating. Yet further, coatings may be applied that strengthen the capillary, increasing its flexibility under pressure, and/or reducing the tendency of breaking off. The invention further relates to a device for deep tissue probing, comprising the needle according to the invention.
Furthermore, the surface of the outside or inside of the needle wall can be modified. This may advantageously allow for tuning the rigidity of the needle, to provide, or enhance electrical conductivity allowing the needle to be used as an electrode, or to attract or release certain compounds.
In a further aspect, the invention further relates to a process for probing or injection into deep tissue, comprising a) providing a needle according to the invention, and b) inserting the needle into a tissue to inject material and/or extract material. The insertion may also be performed to selectively measure the release of certain metabolites, and/or to diagnose certain conditions, which may also be done in vivo, as well as for the stimulation of certain tissues.
The present process further relates to a method of where the needle is coated with a conductive layer so an electrical response, e.g. in brain tissue can be measured directly, or after a certain compound has been injected with the needle into the brain tissue.
The invention further relates to a multitude of cannulae assembled into a microarray of high aspect needles, and to devices comprising one or more cannulae according to the invention.
The present invention further advantageously relates to a process for handling tissue material, comprising a) providing one or more cannulae according to the invention, and b) providing tissue material; and c) handling the tissue material using the one or more cannulae. Preferably, the handling of tissue material comprises probing and/or injection of an injectable material into the tissue material.
The present invention further advantageously relates to a process for recording and/or stimulating intracellular activity, comprising d) filling the cannulae with a conducting medium and connecting the cannula to a measurement apparatus; or using a conductive cannula connected to a measurement apparatus; e) penetrating a cell membrane, and f) recording and/or stimulating cell activity.
The present invention also relates to a tool for supporting one or more of cannulae when subjected to the process according to the invention, comprising one or more flexible parts , each of which seals an area of the outside surface of each cannula from being in contact with the etching liquid or vapours during the execution of the etching step.
The present invention also relates to the use of one or more hollow cannulae according to the invention, or obtainable according to the process according to invention as tissue probing device, nanoelectrospray ionisation source, painless injection needle, for the handling of tissue material, recording or stimulation of tissue or cells, for the ocular or single cell probing, including IVF, and/or for release of compounds into tissue.
The present invention also relates to the use of one or more solid cannulae according to the invention, for light transfer and/or focussing, and/or light based stimulation or recording.
The finished needle may further preferably be subjected to a secondary etch to make the material porous, resulting in cannulae useful as electrospray emitters.
Yet further, the present invention also relates to the use of a cannula for deposition, for use of the needle for removal of compounds (after injection, after dipping into a medium and from a fluid like air or gas); and as a non-clogging ESI emitter.
In a further preferred embodiment, applying a coating over the needle may allow for the formation of a membrane at the distal end of the tip, permitting the use of such a cannula for microdialysis and electro-microdialysis.
Conventional intramuscular or subcutaneous injections of vaccines cause pain and stress, carry the risk of infection and need trained personnel. By only piercing the top layers of the skin, microneedles can be used for minimally invasive, pain free vaccine delivery to an immunologically active site.
The subject invention also relates to a method for for painless intradermal vaccine delivery using the hollow microneedles according to the invention. In this methid, one or more microneedles are preferably used in combination with an automated applicator, for instance advantageously electromagnetic applicator to control the insertion speed, depth, and or angle for painless intradermal vaccine delivery.
The following, non-limiting examples illustrate the invention:
Example 1 : Small Inner Diameter Needle
A needle with a cylindrical inner geometry was fabricated by chemical etching in a diffusion-rate limited regime. The fabrication employed a polyimide coated, fused silica tubing usually employed for gas chromatography. First, the capillary was filled with silicon oil by capillary force. The capillary was then immersed into 49%wt. HF solution in a depth of several centimetres, for a period of several hours at room temperature, while capillary above the etchant was exposed to the gaseous atmosphere above the etchant.
After 2 hours of immersion, the capillary delaminates from polyimider coating as the spce between the fused silica and the polyimide becomes larger. During the next hours, this intermediate space increases. In the periode off from 1 1 to 18 uur etching ultra high aspect ratio needles are formed (Figure 2).
Example 2: Intracerebral Injection into Rat Brains
A needle according to example 1 was connected to a injection device, and a coloured fluid was injected into rat brain tissue. As comparative example, a commercially available and widely applied injection needle was employed.
The results are depicted in Fig. 3, showing a cut of brain tissue after three different injections into ventricles, and injecting Evans Blue to show the damage through the injection (track 2 as the result of a conventional small needle, tracks 1 and 3 by needles according to the subject invention).
Example 3: Subcutaneous injections of vaccines
Hollow microneedles with an inner diameter of 20 pm were used to immunize rats with an inactivated poliovirus vaccine by an intradermal microinjection of 9 μΙ_ at a depth of 300 pm and an insertion speed of 1 m/s. Intradermal microinjection induced comparable immune responses to conventional intramuscular injection, demonstrating
the potential of the subject microneedles for pain free, minimally invasive intradermal vaccination.
Polyimide coated fused silica capillaries (Polymicro, Phoenix AZ, USA, 375 pm outer diameter, 20 pm inner diameter) were wet etched into microneedles. First, the lumen of the capillaries was filled with silicone oil AK350 (Boom Chemicals, Meppel, the Netherlands) to protect the inside of the capillary from the etchant. Subsequently, to etch the capillaries into microneedles, batches of up to 81 capillaries were mounted in a holder with one end suspended in 49% (w/w) HF, as shown in figure 4. The length of the capillary that is immersed in HF could be adjusted by the level of HF in the container as well as by the position of the screws of the holder during mounting. The shape of the microneedle tip was investigated as a function of etching time up to 30 hours. The microneedles chosen for the intradermal injections were etched for 4 hours. In order to connect the microneedles to the applicator, the sharp capillaries were glued into Luer adapters using medical grade glue (Loctite M-31 CL, Henkel, Dusseldorf, Germany). Luer adapters were acquired by removing the needle from Microlance® 26G hypodermic needles (BD, Franklin Lakes, NJ, USA). Finally, the polyimide coating was removed from the microneedles by submersion of the etched capillaries into hot sulfuric acid (96-98%, Boom chemicals, Meppel, the Netherlands) for 5 min at 200°C, and the silicone oil was removed by flushing the microneedles with acetone.
In order to enable insertion of the microneedles into the skin to a controlled depth in a reproducible way, an applicator for hollow microneedles was developed. The flexibility of the skin can hamper skin penetration and reduce the depth accuracy of injections. The insertion speed, insertion depth, and angle of insertion are important factors to overcome this and achieve successful depth controlled penetration and drug delivery. The applicator shown in Figure 5 used an electromagnet (a) to insert the microneedle mounted on the Luer connection (c) into the skin. The electromagnet was actuated using a controllable power source. Application of a variable current through the electromagnet allows for a tuned insertion speed from 1 -3 m/s. Furthermore, the controlled power supply regulates the wear time, to accurately and reproducibly control the time the microneedle is kept inside the skin. For injection, the skin is placed on a platform positioned below the injector (g). The penetration depth is controlled by a supporting plateau (d) that can be adjusted with a micrometer actuator (b). The position of the supporting plateau is adjusted so that the microneedle protrudes the desired distance through the hole in the plateau when the electromagnet is actuated. Before
injection the injector is lowered so the supporting plateau rests on top of the skin. Upon actuation the needle is inserted into the skin at the desired speed and depth, as controlled by the current and plateau position. Additionally the entire applicator can be tilted along a graduated rail (e) for angled insertion (15°-90° relative to the skin). Insertion at a shallow angle can be used to insert a greater length of the needle into the skin, without penetration into deeper skin layers. The hollow microneedles were attached to a syringe pump that was equipped with a gas tight Luer lock 100 μΙ_ syringe and connected to a fused silica capillary with a diameter of 100 pm (f) to allow tuning of the liquid delivery rate.
To determine the microneedle insertion depth, fluorescently labeled human skin was used. Ex vitro abdominal or mammary human skin, which was obtained within 24 h after cosmetic surgery, was dermatomed to a thickness of 1200 pm using a Padgett Electro Dermatome Model B (Kansas City, MO, USA) after the fat was removed. The dermatomed skin was incubated overnight on filter paper soaked with 10 pg/mL fluorescein (Fluka®, Sigma-Aldrich, Steinheim, Germany) with the stratum corneum side to the surface in a Petri dish at 4°C. Before the skin was used for experiments, it was stretched on a piece of expanded polystyrene covered with parafilm, and thereafter the surface of the skin was cleaned 3 times with phosphate buffered saline (PBS) (Braun, Melsungen, Germany, pH 7.4, 163.9 mM Na+, 140.3 mM CI-, 8.7 mM HPO42-, and H2PO4-). Subsequently, a microneedle was connected to the Luer connection on the microneedle applicator (figure 5c) and the micrometer actuator (figure 5d) was adjusted to a chosen depth up to 400 pm. In order to accurately set the insertion depth, the microneedle position was calibrated. First, the electromagnet was actuated and the microneedle was positioned to be flush with the plateau using the micrometer actuator (figure 5a). This was done by laser alignment, by which a laser was put perpendicular to the supporting plateau of the applicator (figure 5d). When a microneedle protrudes past the supporting plateau the laser light is scattered at the tip of the microneedle, therefore the needle was determined to be flushed with the plateau at the point where no light scattering was observed at the microneedle tip. After this calibration of the microneedle position, the microneedle actuator was adjusted to a depth of 100, 200, 300, or 400 pm, and was subsequently pierced into the fluorescently labeled human skin. For each chosen depth 3 microneedles were used to pierce the skin and each microneedle stayed in the skin for 5 s. After the microneedles had pierced the fluorescently labeled skin, the microneedles were analyzed by bright field microscopy and by fluorescence
microscopy (Nikon Eclipse E600, mercury light source, GFP filter set) at 100x magnification and imaged with a 1 s exposure time. Subsequently, the bright field and fluorescence microscopy images were overlaid in ImageJ (available from rsbweb.nih.gov/ij/), and the insertion depth was expressed as the measured length between the tip of the microneedle and the part up to where the fluorescence was visible.
Microinjection into skin
To visualize the intradermal injections, a 10 pg/mL fluorescein solution in PBS was injected into human ex vivo skin at different depths (100-400 pm). The skin was stretched on Styrofoam covered with parafilm, and the injection depth was adjusted as described above. The microneedle was connected to a syringe pump with a flow rate of 2 pL/min to deliver 3 μΙ_ of the fluorescein solution. As a negative control 3 μΙ_ of the fluorescein solution was dispensed on top of the skin. Furthermore, diffusion of the injected compound into surrounding tissue was assessed by imaging the fluorescence in the skin at several time points after injection. The fluorescence was imaged using a Microsoft Lifecam HD with a 480±5 nm light source (LED, Conrad) and a 520-540 nm band pass interference filter.
Immunization
To examine the applicability of the hollow microneedles for vaccination purposes, a comparison was made between vaccination of rats by intradermal injection with microneedles, and intradermal and intramuscular injection with a conventional needle.
Female Wistar Han rats (175-250 g) were obtained from Charles River (Maastricht, the Netherlands) and were maintained under standardized conditions in the animal facility of the Leiden Academic Centre for Drug Research, Leiden University. The study was carried out under the guidelines complied by the animal ethic committee of the Netherlands. Rats (10 per group) were immunized with 5 DU (1/8th human dose) IPV-type-1 (1 DU«13 ng virus protein, obtained according to Westdijk, J., et al., Characterization and standardization of Sabin based inactivated polio vaccine: Proposal for a new antigen unit for inactivated polio vaccines. Vaccine, 201 1 . 29: p. 3390-3397) intradermal^ by hollow microneedles at an apparent depth of 300 pm and a flow speed of 2 pL/min for 4.5 minutes. For comparison, rats were immunized with 5 DU IPV/50 μί intradermal^ on the belly with a 30G needle and with 5 DU IPV/200 μί intramuscularly with a 26G needle (100 L/hind leg). As a negative control rats were injected intramuscularly with 200 μί PBS (100 pL/leg). All rats were anesthetized during the
immunization with 50 mg/kg ketamine (Nimatek® (100 mg/mL Ketamine, Eurovet Animal Health B.V., Bladel, the Netherlands)) and 5 mg/kg xylazine (Rompun® (20 mg/mL xylazine, Bayer B.V., Mijdrecht, the Netherlands)) by intraperitoneal injection. Three weeks after immunization blood samples were collected and the rats were sacrificed. This immunization scheme is identical to the regular IPV potency assay, as described in an Steenis, G., A. van Wezel, and V. Sekhuis, "Potency testing of killed polio vaccine in rats", Developments in biological standardization, 1981. 47: p. 1 19-128.
IgG ELISA
Polystyrene 96 wells microtiter plates (Greiner Bio-One, Alphen a/d Rijn, the Netherlands) were coated overnight at 4°C with bovine anti-poliovirus type 1 serum (RIVM, Bilthoven, The Netherlands) in PBS pH 7.2 (Gibco from Invitrogen, Paisley, UK). After washing with 0.05% Tween 80 (Merck, Darmstadt, Germany) in tap water, 100 μΙ/well monovalent IPV vaccine type 1 (4.5 DU/well) diluted in assay buffer, PBS containing 0.5% (w/v) Protifar (Nutricia, Zoetermeer, the Netherlands) and 0.05% (v/v) Tween 80 (Merck, Darmstadt, Germany), was added. After incubation at 37°C for 2 hours, threefold dilutions of sera samples in assay buffer were added (100 μΙ/well) and incubated at 37°C for 2 hours. After washing, plates were subsequently incubated at 37°C for 1 hour with horseradish peroxidase (HRPO)-conjugated goat-anti-rat IgG (Southern Biotech, Birmingham, AL) as detection antibody (4000 fold dilution, 100 μΙ/well). Plates were extensively washed and 100 μΙ/well TMB substrate solution, containing 1 .1 M sodium acetate (NVI, Bilthoven, the Netherlands), 100 mg/ml 3, 3', 5,5'- tetramethylbenzidine (Sigma-Aldrich, St. Louis, MO), and 0.006% (v/v) hydrogen peroxide (Merck, Darmstadt, Germany), was added. After 10-15 minutes, the reaction was stopped with 100 μ l/well 2M H2SO4 (NVI, Bilthoven, the Netherlands) and absorbance was measured at 450 nm by using a Biotek L808 plate reader.
Endpoint titers were determined by 4-parameter analysis using the Gen5™ 2.0 Data Analysis software (BioTek Instruments, Inc., Winooski, VT) and defined as the reciprocal of the serum dilution producing a signal identical to that of antibody-negative serum samples at the same dilution plus three times the standard deviation, as disclosed in Westdijk, J., et al. cited above, and Westdijk, J., et al., Antigen sparing with adjuvanted inactivated polio vaccine based on Sabin strains. Vaccine, 2013. 31 : p. 1298-1304.
Virus neutralizing antibodies
Virus neutralizing (VN) antibodies against poliovirus type 1 were measured as described in Westdijk, J., et al., above. In brief, the sera were inactivated at 56°C for 30 min prior to testing, of which 2 fold serial dilutions were made (21 to 224). These dilutions were incubated with 100 cell culture infectious dose 50% (CCID50) of wild type poliovirus type 1 (Mahoney) for 3 hours at 36°C and 5% C02, and the resulting mixtures were subsequently used to inoculate 1 ·104 Vero cells. Virus-neutralizing antibody titers were determined after 7 days by staining the cells with crystal violet and expressed as the last serial dilution with an intact monolayer.
Statistical analysis
The statistical analysis was performed using Prism 5 for Windows, where the mean ± SEM (n=10) of the IgG and VN titers were calculated. Furthermore, statistical significance was determined by a two way analysis of variance (ANOVA) with a Bonferroni post test.
Production of microneedles: Influence of etch time
The microneedle geometry was observed to be dependent on etch time. The different tip shapes that were obtained after 1 , 2, 4, 9, 22 and 29 hours of etching are depicted in figure 2 (n=3). Less than four hours of etching resulted in blunt needles with strong etching of the lumen of the capillary. Etch times between 4 and 22 hours resulted in increasingly long, thin needles of up to 4 cm. Longer etching resulted in fully dissolving extended portions of the capillary, leaving a short microneedle with an irreproducible tip shape.
The observed lumen shapes are caused by displacement of the silicone oil. At the start of etching a small amount of HF is sucked into the lumen by capillary force, etching a short length from the inside. After 4 hours this portion is fully etched away, leaving only the part of the capillary that was protected from inside etching (figure 2c, h).
The outer shape of the needle can be explained by the interaction between the HF and the polyimide coating. The coating is slightly permeable to HF. When HF permeates through the coating it slowly etches the fused silica and delaminates the coating and the fused silica. When the coating is separated from the capillary, HF is sucked in between by capillary force. This HF results in the strong etching that determines the final tip shape. As HF supply through the coating is small, mass transport by diffusion from the tip is limiting the etch rate, resulting in slower etching further away from the tip. This gradient in etch rate results in the sharp tip of the microneedle.
Gluing the microneedles into Luer adapter resulted in needles that can be used and connected with the ease of conventional needles (figure 2).
The relatively short needles obtained by 4 hours of etching were most suitable for injection into the skin because of their rigidity and robustness. While not suitable for injections into the skin, the extremely long needles can be useful for other applications. The ultra-high aspect ratio of these needles (4 cm long, 20 pm tip diameter, figure 2i) could be very useful for deep penetration into soft fragile tissue, e.g. for intracerebral injections.
Applicator
Microneedle applicators are preferably employed or controlled and reproducible microneedle application and reduce the required insertion forces to pierce the stratum corneum for both solid and hollow microneedles.
The microneedle applicator advantageously used in this work was particularly useful for in- and ex-vivo microinjections with easily adjustable insertion speed, depth, angle, and flow rate. Robust performance was observed, i.e. at an insertion speed of 1 m/s no damage of the needles was observed.
In order to construct the system to be completely air free, gas tight syringes and Luer lock connections combined with pressure resistant fused silica tubing were used. This enables constant flow generation at high pressures. As such, the system could be used at relatively high flow rates without using hyaluronidasem, at 2 pL/min, as compared to literature values of single microneedle injections of 50-300 nL/min.
The present sytem comrpsiing the needle sadn applicator was found to to aloe higher flow rates as compared to those disclosed for other systems in the literature, which may have been limited by the maximum applicable pressure in systems using common flexible tubing and different pump types.
The full tunability of the device was found very valuable in a research setting, where varying injections into different skin types and layers are required. Whilst completely compatible with use for intradermal microinjections in in vivo arms of humans, the freestanding setup of the device was also particularly suitable for use in animal studies, as it allows for easy handling of the animals.
It is envisioned that a microneedle applicator for routine use may not need the tunability and flexibility offered by the applicator embodiment disclosed above. Hene, the principles may also be applied in a simplified, hence cheaper, handheld device suitable for large scale immunizations.
Determination of microneedle insertion depth
It is important to control the depth of hollow microneedle insertion into the skin, since this defines whether or not the microneedle injection causes pain and/or bleedings. Figure 7a-c depicts micrographs of microneedles after instertion into fluorescently labeled ex vivo human skin with a velocity of 1 m/s. The distance between the fluorescent dye transferred from the skin and the tip of the needle was used to measure penetration depth. Figure 4d shows that the measured microneedle insertion depth was on average 1 10±36 pm (mean±SD, n=4) deeper than the aimed microneedle insertion depth. This bias towards a deeper microneedle insertion than the aimed depth could be due to the pressure that is applied by the microneedle applicator supporting plateau onto the skin, causing the skin to bulge into the opening in the plateau (figure 7G). However, when corrected for this bias, this applicator for hollow microneedles enables us to accurately and reproducibly insert a microneedle into the skin at a chosen depth. The shown depth accuracy is sufficient to selectively inject into the dermis in rats and would allow for even more control in the relatively thick human skin.
Microinjection into skin
Intradermal injections where visualized by injection of 3 μΙ_ fluorescein at a flow speed of 2 L/min into ex vivo human skin. Successful injections were observed at all the injection depths that were tested (100-400 pm). As depicted in figure 7, fluorescence from the injected fluorescein was observed below the surface of the skin. No leakage was observed and diffusion into surrounding tissue was indicated by an increasing area of low fluorescence around the injection site. The negative control of fluorescein dispensed on top of the skin showed fast evaporation of the solvent, causing rapid loss of fluorescence intensity. No significant difference in fluorescence intensity between penetration depths from 100-400 pm was observed in the skin (data not shown).
Immunization study
In order to test the applicability of the hollow microneedles for dermal vaccination, rats were immunized with IPV serotype 1. The resulting antibody titers are shown in figure 6. This figure shows that the serum IgG responses after the (intradermal) microinjections with hollow microneedles at a depth of 300 pm are comparable with those after conventional intramuscular immunization and intradermal immunization, and were comparable to IgG responses described in Westdijk, J., et al., above after a single intramuscular immunization with 5 DU IPV type 1 . Furthermore, a higher dose IPV (15
DU) delivered by a microinjection of 9 μΙ_ led to a significant increase of the IgG response as compared to 5 DU microinjection, but no significant difference between either microneedle injection groups and the intramuscular or intradermal group with 5 DU IPV was observed.
Besides the serum IgG responses, the rat sera were analyzed for VN antibodies, as shown in figure 8. Despite the slightly lower VN titers of rats intradermal^ immunized with a microinjection of 5 DU, compared to conventional intramuscular immunization, this difference was not significant. However, there was a significant difference between 5 DU microinjections and 5 DU intradermal immunization. The lower VN titer of the microinjection might be caused by reduced damage of the skin compared to intradermal injection, where the needle is much thicker, is injected at a greater depth, and a larger volume is injected. This intrinsic effect of less invasive injections might be overcome by adding an adjuvant to the IPV suspension, as described for instance in Bal, S.M., et al., Advances in transcutaneous vaccine delivery: do all ways lead to Rome? Journal of Controlled Release, 2010. 148(3): p. 266-282, and Westdijk, J., et al., above. Furthermore, the immune responses by intradermal injection might be higher than by intramuscular injection after booster immunizations, since intradermal immunization can lead to accelerated booster responses, as described in Nicolas, J.-F. and B. Guy, Intradermal, epidermal and transcutaneous vaccination: from immunology to clinical practice. Expert Review Vaccines, 2008. 7(8): p. 1201 -1214. Therefore, in future experiments the insertion depth (50-1000 pm), the volume effect (3-50 μΙ_), and the booster effect (up to 3 immunizations) should be evaluated. However, a higher dose of IPV by microinjections led to comparable VN titers compared to intradermal and intramuscular immunization. Therefore, these data show the applicability of microneedles to successfully induce VN antibodies against polio-virus.
The experimental results clearly indicate that the needle canulla according to the invention allow to penetrate tissue with much reduced damage as compared to conventional needles. Furthermore, alternative uses such as nanolectrospray injectors are also feasible. Yet further, their use as painless injection needles was demonstrated successfully; which shows that not only can microneedles be fabricated using a cheap and scalable wet etching method, but also their use with a preferred microneedle applicator for successful intradermal microinjections into human and rat skin.
Intradermal microinjection of IPV showed comparable IgG responses to conventional intramuscular injections or intradermal injections. Furthermore,
immunization with IPV by microinjection led to the induction of VN antibodies. Etched hollow microneedles can offer pain free, minimally invasive intradermal injections for vaccine delivery.
Claims
1 . An ultra-high aspect ratio needle cannula with pointed distal end, the cannula having a maximum outer diameter in the range of from 50 to 2500 pm, and an aspect ratio of the width \N measured at the tip of the pointed distal end to the length L measured from the tip to the beginning of a continuous contraction of the outer diameter of the cannula, in the range of from 1 : 100 to 1 : 1x1010
2. A cannula according to claim 1 , wherein the cannula is solid.
3. A cannula according to claim 1 , wherein the cannula is hollow, and comprises a lumen with an inner diameter in the range of from 5 to 50 pm.
4. A cannula according to claim 3, wherein the inner diameter is constant for at least 95% of the cannula length from the beginning of the continuous contraction of the outer diameter up to the tip at the distal end.
5. A cannula according to any one of the previous claims, having a wall thickness at the tip in the case of a hollow needle, or a total thickness of the tip in the case of a solid needle, in the range of from 100 pm to 500 pm.
6. A cannula according to any one of claims 1 to 5, wherein the material of the cannula comprises of essentially an isotropic, etchable composition, preferably fused silica, glass or pure metals.
7. A cannula according to any one of the previous claims, wherein the cannula is at least in part electrically conductive.
8. A process for the manufacture of an ultra high aspect ratio needle cannula with pointed distal end , comprising the steps of: (i) providing a needle cannula having a proximal end and a distal end and an oblong inside lumen there between;
(ii) at least partly covering the outer surface of the cannula with a protective coating , such that the coating prevents the etchant from directly contacting the outer surface of the cannula other than through diffusion;
(iii) at least partly preventing the etchant liquid from entering the lumen, preferably by coating an inside surface of the lumen with a protective material inert to the etching liquid, and
(iv) contacting the distal end of the cannula with an etching liquid for a suitable period of time to obtain a needle cannula with a pointed distal end an aspect ratio of the width 1/1/ measured at the tip of the pointed distal end to the length L measured from the tip to the beginning of a continuous contraction of the outer diameter of the cannula, in the range of from 1 : 100 to 1 : 1x1010
9. A process according to claim 8, wherein step (iv) is performed by immersion of the distal end of the cannula in the etchant.
10. A process according to claim 9, wherein the distal end of the canulla is immersed in the etchant liquid, while a second portion running from the immersed distal end to the location where the beginning of the continuous contraction of the outer diameter of the cannula is desired, is brought into contact with gaseous etchant liquid.
1 1 . A process according to any one of claims 8 to 10, wherein the material of the cannula is essentially an isotropic, etchable composition, preferably fused silica, glass and/or pure metals.
12. A process according to any one of claims 8 to 1 1 , wherein the etching step (iv) is continued for a period of time until the desired aspect ratio is achieved.
13. A process according to any one of claims 8 to 12, wherein the inner diameter of the cannula is preferably in the range of from 5 to 50 pm.
14. A process according to any one of claims 8 to 13 , wherein the outer diameter of the cannula is in the range of from 10 to 2500 pm.
15. A process according to any one of claims 8 to 14, wherein a multitude of cannulae is assembled into a microarray of high aspect needles.
16. A cannula or array of cannulae manufactured according to the process according to any one of claims 8 to 15.
17. A device comprising one or more cannulae according to any one of claims 1 to 8, or as obtained according to the process according to claim 8 to 15.
18. A process for handling tissue material, comprising
a) providing one or more cannulae according to any one of claims 1 to 8, and b) providing tissue material; and
c) handling the tissue material with the one or more cannulae.
19. A process according to claim 18, wherein handling of tissue material comprises probing and/or injection of an injectable material into the tissue material.
20. A process for recording and/or stimulating intracellular activity according to claim 18 or claim 19, comprising
d) filling the cannulae with a in a conducting medium and connecting the cannulae to a measurement apparatus;
e) penetrating a cell membrane, and
f) recording and/or stimulating cell activity.
21 . A process for the painless injection of fluids into mammals, comprising
(i) penetrating the skin or other suitable tissue to a desired depth with one or more hollow cannulae according to any one of claims 1 to 7, or as obtained according to the process according to claim 8 to 15, and injecting an aliquot of a fluid into the skin or tissue.
22. A process according to claim 21 , wherein the fluid is or comprises a vaccine.
23. A tool for supporting one or more of cannulae when subjected to the process according to claim 8 to 15, comprising one or more flexible parts, each of which seals an area of the outside surface of each cannula from being in contact with the etching liquid or vapours during the etching step.
24. An applicator for controlling the penetration of one or more cannulae according to any one of claims 1 to 7, or as obtained according to the process according to claim 8 to 15, comprising a means for holding the one or more cannulae, and a means for controllably inserting the one or more cannulae into the tissue to a desired penetration depth.
25. Use of one or more hollow cannulae according to any one of claims 1 to 7, or obtainable according to the process according to any one of claims 8 to 15 as tissue probing device, nanoelectrospray ionisation source, painless injection needle, for the handling of tissue material, recording or stimulation of tissue or cells, for the ocular or single cell probing, including IVF, and/or for release of compounds into tissue.
26. Use of one or more solid cannuale according to any one of claims 2 to 7, or obtainable according to any one of claims 8 to 15, for light transfer and/or focussing, and/or light based stimulation or recording.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL2009945A NL2009945C2 (en) | 2012-12-10 | 2012-12-10 | Process and device for minimally invasive deep tissue probing. |
NL2009945 | 2012-12-10 | ||
NL2011323 | 2013-08-20 | ||
NL2011323 | 2013-08-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014092566A1 true WO2014092566A1 (en) | 2014-06-19 |
Family
ID=49780290
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NL2013/050883 WO2014092566A1 (en) | 2012-12-10 | 2013-12-10 | Process and device for minimally invasive deep tissue probing |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2014092566A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017198872A1 (en) | 2016-05-20 | 2017-11-23 | Uprax | System and method for applying microneedles |
NL2016807B1 (en) * | 2016-05-20 | 2017-11-27 | Uprax | System and method for applying microneedles |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2814296A (en) | 1954-04-15 | 1957-11-26 | S & R J Everett & Co Ltd | Surgical needles |
US3826244A (en) * | 1973-07-20 | 1974-07-30 | Us Health Education & Welfare | Thumbtack microelectrode and method of making same |
US4469554A (en) | 1983-04-05 | 1984-09-04 | At&T Bell Laboratories | Etch procedure for optical fibers |
US6249965B1 (en) * | 1997-10-15 | 2001-06-26 | Huntington Medical Research Institutes | Methods for making small-diameter iridium electrodes |
US20060129126A1 (en) * | 2004-11-19 | 2006-06-15 | Kaplitt Michael G | Infusion device and method for infusing material into the brain of a patient |
US20070282265A1 (en) | 2004-05-31 | 2007-12-06 | Institute Of Whole Body Metabolism | Hollow Needle and Indwelling Needle Using the Hollow Needle |
US20100318061A1 (en) * | 2007-10-08 | 2010-12-16 | Renishaw (Ireland) Limited | Catheter |
US20120138335A1 (en) * | 2008-06-03 | 2012-06-07 | University Of Utah Research Foundation | High Aspect Ratio Microelectrode Arrays Enabled to Have Customizable Lengths and Methods of Making the Same |
-
2013
- 2013-12-10 WO PCT/NL2013/050883 patent/WO2014092566A1/en active Application Filing
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2814296A (en) | 1954-04-15 | 1957-11-26 | S & R J Everett & Co Ltd | Surgical needles |
US3826244A (en) * | 1973-07-20 | 1974-07-30 | Us Health Education & Welfare | Thumbtack microelectrode and method of making same |
US4469554A (en) | 1983-04-05 | 1984-09-04 | At&T Bell Laboratories | Etch procedure for optical fibers |
US6249965B1 (en) * | 1997-10-15 | 2001-06-26 | Huntington Medical Research Institutes | Methods for making small-diameter iridium electrodes |
US20070282265A1 (en) | 2004-05-31 | 2007-12-06 | Institute Of Whole Body Metabolism | Hollow Needle and Indwelling Needle Using the Hollow Needle |
US20060129126A1 (en) * | 2004-11-19 | 2006-06-15 | Kaplitt Michael G | Infusion device and method for infusing material into the brain of a patient |
US20100318061A1 (en) * | 2007-10-08 | 2010-12-16 | Renishaw (Ireland) Limited | Catheter |
US20120138335A1 (en) * | 2008-06-03 | 2012-06-07 | University Of Utah Research Foundation | High Aspect Ratio Microelectrode Arrays Enabled to Have Customizable Lengths and Methods of Making the Same |
Non-Patent Citations (7)
Title |
---|
"Fabrication Process of Microsurgical Tools for Single-Cell Trapping and Intracytoplasmic Injection", JMEMS, vol. 13, no. 6, December 2004 (2004-12-01), pages 940 - 945 |
BAL, S.M. ET AL.: "Advances in transcutaneous vaccine delivery: do all ways lead to Rome?", JOURNAL OF CONTROLLED RELEASE, vol. 148, no. 3, 2010, pages 266 - 282 |
NICOLAS, J.-F.; B. GUY: "Intradermal, epidermal and transcutaneous vaccination: from immunology to clinical practice", EXPERT REVIEW VACCINES, vol. 7, no. 8, 2008, pages 1201 - 1214 |
PAK KIN WONG ET AL.: "Fabrication Process of Microsurgical Tools for Single-Cell Trapping and Intracytoplasmic Injection", MICROELECTROMECHANICAL SYSTEMS, vol. 13, no. 06, December 2004 (2004-12-01), XP002714824 * |
STEENIS, G.; A. VAN WEZEL; V. SEKHUIS: "Potency testing of killed polio vaccine in rats", DEVELOPMENTS IN BIOLOGICAL STANDARDIZATION, vol. 47, 1981, pages 119 - 128 |
WESTDIJK, J. ET AL.: "Characterization and standardization of Sabin based inactivated polio vaccine: Proposal for a new antigen unit for inactivated polio vaccines", VACCINE, vol. 29, 2011, pages 3390 - 3397 |
WESTDIJK, J.: "Antigen sparing with adjuvanted inactivated polio vaccine based on Sabin strains", VACCINE, vol. 31, 2013, pages 1298 - 1304 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017198872A1 (en) | 2016-05-20 | 2017-11-23 | Uprax | System and method for applying microneedles |
NL2016807B1 (en) * | 2016-05-20 | 2017-11-27 | Uprax | System and method for applying microneedles |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
van der Maaden et al. | Novel hollow microneedle technology for depth-controlled microinjection-mediated dermal vaccination: a study with polio vaccine in rats | |
Ma et al. | Microneedle, bio-microneedle and bio-inspired microneedle: A review | |
Larrañeta et al. | Microneedle arrays as transdermal and intradermal drug delivery systems: Materials science, manufacture and commercial development | |
Chen et al. | Dry-coated microprojection array patches for targeted delivery of immunotherapeutics to the skin | |
US9302903B2 (en) | Microneedle devices and production thereof | |
JP5559054B2 (en) | Delivery device and method | |
US20080269666A1 (en) | Microneedles and Methods for Microinfusion | |
US10821276B2 (en) | System and method to locally deliver therapeutic agent to inner ear | |
JP2019500980A (en) | Microneedles and tips | |
Giri Nandagopal et al. | Overview of microneedle system: a third generation transdermal drug delivery approach | |
US20120089117A1 (en) | Apparatus that includes nano-sized projections and a method for manufacture thereof | |
Vaidya et al. | Microneedles. Promising Technique for Transdermal Drug Delivery | |
JP2002517300A (en) | Microneedle devices and methods of manufacture and uses thereof | |
Singh et al. | Microneedles for drug delivery and monitoring | |
KR20170108049A (en) | Micro needle array and method of use | |
CN110090044A (en) | A kind of hydrogel microneedle patch for acquiring skin interstitial fluid and preparation method thereof and application method | |
Horn et al. | In vivo microdialysis for nonapeptides in rat brain—a practical guide | |
Koelmans et al. | Microneedle characterization using a double-layer skin simulant | |
Xuan et al. | Fabrication and use of silicon hollow-needle arrays to achieve tissue nanotransfection in mouse tissue in vivo | |
CN107245431A (en) | A kind of microinjection device precisely injected for cell drug and its operating method | |
Das et al. | Development of silicon microneedle arrays with spontaneously generated micro-cavity ring for transdermal drug delivery | |
WO2014092566A1 (en) | Process and device for minimally invasive deep tissue probing | |
Jurčíček et al. | Design and fabrication of hollow out‐of‐plane silicon microneedles | |
CN209917068U (en) | Monocrystalline silicon high-flux microneedle structure | |
ES2369472T3 (en) | MICRO-INVASIVE LIVE RESEARCH DEVICE THAT INCLUDES A METAL GUIDE. |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 13808268 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 13808268 Country of ref document: EP Kind code of ref document: A1 |