WO2009090174A1 - Composite membrane blends comprising ionic branch polymers and methods of use - Google Patents

Abstract

The invention is directed towards a composite membrane comprising an ionic branch polymer and at least one other polymer, to form a polymer blend. The branch polymer is an ionic polymer and typically is selected from dendrimers, arborols, polycations, polyanions and polyamphiphiles, including in certain instances polethylenimine (PEI) or dextransulfate. The other polymer is typically nitrocellulose. Such membranes of the invention may be further comprised of one or more organic solvents and one or more surfactants.

Description

COMPOSITE MEMBRANE BLENDS COMPRISING IONIC BRANCH POLYMERS AND METHODS OF USE

BACKGROUND

Composite membianes can be used foi a vanety of puiposcs, such as miciofiltiation membianes, ulliafilti ation membianes, gas sepaiation membianes, pcπ apoiation membianes, and ie\ cise osmosis membianes A composite membiane may be piepaicd by intei facial polymenzation, modification of membi anes, and dip coating Dip coating is widely used in oidei to piepaie the composite membiane, by using a poious membiane such as a filtiation membi ane as a suppoit layei, coating the poious membiane with a solution of a matenal used as an active layei, and diying the coated membiane The composite membiane piepaied by dip coating has a suppoit layei compiising legulaily-sized poies, and an active layei having a dense stiuctuie with few poies The composite membiane is limited in application, since the active layei has few poies of a size similai to those of the vaπous filtiation membianes, and it is easily delammated due to a weak mtei facial adhesion stiength between the suppoit layei and the active layei

Alternatively, composite membiane may be piepaied by coating a polymei on the poious membiane as disclosed in U S Pat Nos 3,249,109, 4,388,189, and 5,102,552 In addition, a hydiophilic monomei, such as an aciylic acid, and polymei s such as polyethylene oxide aie giafted with coiona treatment so that the membiane has a modified suiface, and in paiticulai so that it has hydiophilicity as disclosed in U S Pat Nos 4,346,142, 5,085,775, and 5,294,346 Howevei, though the membiane has a modified suiface and hydiophilicity, the method of giaft polymei izati on is not applied, since the piocess is complicated and permeability of the membiane is not satisfactoiy

Composite polyamide membianes aie also piepaied by coating a poious support with a polyfunctional amine, most commonly coated fiom an aqueous solution Although aqueous solutions aie piefened, non-aqueous solutions may be utilized, such as acetyl nitiile and dimethylformamide (DMF) A polyfunctional acyl hahde is subsequently coated on the suppoit, typically horn an oiganic solution Although no specific oidei ol addition is necessatily lequiied the aqueous amine solution is typically fust coated on the poious suppoit followed by the oiganic acyl halide solution Although one 01 both ol the polyiunctional amine and acyl halide may be applied to the poious suppoit fiom a solution, they may alternatively be applied by othei means such as by \ apoi deposition

Means loi lmpioving the peifoimance of membianes by the addition of constituents to the aqueous amine and/oi oiganic acyl halide solutions aie desci ibed in the hteiatuie Foi example, U S Pat No 4,950 404 desci ibes a method foi inci casing flux of a composite membianc by adding a polai apiotic solvent and an optional acid acceptoi to the aqueous amine solution pnoi to inteitacially polymei i/ing the amine with a polycaiboxyhc acid halide Similaily, U S Pat No 5,989,426 desci ibes the addition of selected alcohols, etheis, ketones, estei s, halogenated hydiocaibons, mtiogen- contammg compounds and sulfui -containing compounds having a solubility paiametei of 8 to 14 (cal/cm^J)' ² to eithei the aqueous amine solution oi oiganic acid halide solution pi ioi to mtei facial polymeπzation

Methods of impiovmg membiane piefoπnance by post-tieatment aie also known Foi example, U S Pat No 5,876,602 desciibes ti eating a polyamide composite membiane with an aqueous chloi mating agent to impiove flux, lowei salt passage, and/oi mciease membiane stability to base U S Pat No 5,755,964 discloses a piocess wheiein the polyamide disci immating layei is tieated with ammonia oi selected amines, e g , butylamme, cyclohexylamme, and 1 ,6 hexane diamine U S Pat No 4,765,897 discloses the post tieatment of a membiane with a stiong mmeial acid followed by tieatment with a lejection enhancing agent U S Pat Nos 4,765,897, 5,876,602 and 5,755,964 aie mcoipoiated heiein by iefeience

It is theiefoie a goal of the piesent invention to piovide novel and impioved composite membianes This and othei objects of the invention will be appaient fiom a leading of the following detailed desciiption of piocesses foi making composite membianes embodying vanous featuies of the invention

SUMMARY OF THE INVENTION In one aspect the im ention is diiectcd tow aids a composite membiane compiismg an ionic blanch polymei and at least one othei polymei, to form a polymei blend The blanch polymei is an ionic polymei and typically is selected fiom dcndnmeis, aiboiols, polycations, polyamons, and polyamphiphiles including in ceitam instances polethylenimme (PEI), dextiansulfate 01 polyunylimidazole The othei polymei is typically mtiocellulosc Such membianes of the im ention may be fuithci compiised of one 01 moie oiganic solvents and one 01 moie suifactants

In anothci aspect, the invention pio\ ides a membiane compiismg polyethylenimine, nitiocellulose, an oiganic soh ent, and a suifactant In ceitam instances, the polyethylenimine compπses about 0 01 % to about 2 0% of the membiane, the nitiocellulose compπses about 8% to about 1 1% of the membiane the oiganic solvent compiises about 50% to about 80% of the membiane, and m othei instances, the sui factant compiises about 5 0% to about 8 0% of the membiane

In anothei aspect, the invention piovides a membiane compiismg dexttan sulfate, nitiocellulose, an oiganic solvent, and a suifactant

In one aspect, the invention piovides a method foi binding a taiget molecule, compiismg contacting the taiget molecule with a poious membiane compiismg an ionic bianch polymei and at least one othei polymei, and detecting whethei binding has occui ied between the membiane and the taiget compound, wheiein the membiane compiises a pluiahty of poies, and wheiein the poies bind to a taiget molecule

In anothei aspect, the invention piovides a device foi binding at least one taiget molecule, compiismg a poious membiane compiismg an ionic bianch polymei and at least one othei polymei

DETAILED DESCRIPTION

Bt ief Description of the Dtawmgs

FIG 1 Figuie IA shows a SEM image of a tot initiation of the invention on glass, Figuie IB and Figuie 1 C shows a formulation of the invention having -60% highei binding The spots have a bull's eye piofile, which is ieflected in the intensity plot

FIG 2 Figuie 2A shows a SEM image of a standaid nitiocellulose foimulation on glass, Figuie 2B and Figuie 2C shows that the standaid nitiocellulose formulation has low ci binding The spots typically ha\ e a tiough piofilc, w hich is ieflected in the intensity plot When compaied to the spotting horn the foimulation ot Figuie 1 , the coloiation seen on the spotting is im eitcd at the tiough

Definitions

The tcims "blend" and "composite" membiane ai e used mtetchangeably thioughout and ietei to a membiane compiising at least tw o ditfeicnt polymei s, one ot w hich is an ionic dendnmei, aiboiol, polycation, polyanion 01 polyamphiphile

The teims "compound," "species," 01 "taiget," when used in icfei ence to binding applications, aie used inteichangcably and ielei to taiget compounds consisting of small molecules, maciomolecules, pai tides and cellulai systems, e g , nucleic acids, pioteins and ligands, which aie ietained to a membiane of the invention

The teim "detectable quantity" is intended to mean a sufficient quantity of ietained compound, species, 01 taiget piesent such that it may be measuied, identified 01 otheiw ise detected by quantitative 01 qualitative analysis Detection of such compounds oi species in membianes can be made by way of any suitable analytical technique, including but not limited to mass spectioscopy, liquid chiomatogi aphy mass spectioscopy (LC-MS), gas chiomatogiaphy mass spectioscopy (GC-MS), secondaiy ion mass spectioscopy, NMR, IR, X-iay fluoiescence (XRF), and caloiimetiic analysis

The teim "ietained" is intended to mean that compounds 01 species which iemain associated (e g , covalently bonded, complexed, weakly bound, etc ) with the composite membiane aftei being eluted onto the membiane

The teim "liquid chiomatogiaphy" is ait-iecognized and includes chiomatogiaphic methods m which compounds aie paititioned between a liquid mobile phase and a solid stationaiy phase Liquid chiomatogiaphic methods aie used foi analysis 01 puiifϊcation of compounds The liquid mobile phase can have a constant composition thioughout the pioceduie (an isociatic method), 01 the composition of the mobile phase can be changed dining elution (e g , a giadual change in mobile phase composition such as a giadient elution method) The teim "mobile phase" is ait-iecognized, and as used heiein, iefeis to a liquid soh cnt system used to cany a compound of inteiest into contact \\ ith a solid phase and to elute a compound of inteiest fiom the solid phase

As used heiein, the teim "ammo acid" is intended to mean both natuially occuπing and non-natuially occuu ing ammo acids as w ell as amino acid analogs and mimetics Natuially occuuing ammo acids include the 20 (L)-ammo acids utilized dm ing piotein biosynthesis as well as otheis such as 4-hydioxypioline, hydioxylysine, desmosme, isodesmosine, homocysteine, citiulhne and ornithine, toi example Non- natuially occult ing ammo acids include, foi example, (D)-ammo acids, noi leucine, noi\ aline, p-fluoiophenylalanme, ethiomne and the like Ammo acid analogs include modified foims of natuially and non-natuially occuπing ammo acids Such modifications can include, foi example, substitution 01 ieplacement of chemical gioups and moieties on the ammo acid 01 by dem itization of the ammo acid Ammo acid mimetics include, foi example, oiganic stiuctui es which exhibit functionally similai piopeities such as chaige and chaige spacing chaiacteiistic of the iefeience ammo acid Foi example, an oigamc structuie which mimics lysine (Lys 01 K) would have a positive chaige moiety located m similai moleculai space and having the same degiee of mobility as the ε-amino gioup of the side chain of the natuially occuπing Lys ammo acid Mimetics also include constt ained stuictuies so as to maintain optimal spacing and chaige intei actions of the ammo acid 01 of the ammo acid functional gioups

As used heiem, the teim "polypeptide" iefeis to a peptide 01 polypeptide of two 01 moie ammo acids A polypeptide can also be modified by natuially occuπing modifications such as post-tianslational modifications 01 synthetic modifications, including phosphoiylation, hpidation, pienylation, palmitylation, myi istylation, sulfation, hydioxylation, acetylation, glycosylation, ubiquitmation, addition of piosthctic gioups 01 cofactois, foimation of disulfide bonds, pioteolysis, assembly into maciomoleculai complexes, and the like

A polypeptide includes small polypeptides having a few 01 seveial ammo acids as well as laige polypeptides ha\ mg seveial hundied 01 moie amino acids Usually, the covalent bond between the two 01 moie amino acid iesidues is an amide bond Howevei, the amino acids can be joined togethei by vaπous othei means known to those skilled m the peptide and chemical aits Theieloie, the teim polypeptide is intended to include molecules w hich contain, in w hole 01 m pait non-amide linkages betw een ammo acids ammo acid analogs, and mimetics Similaily the teim also includes cyclic polypeptides and othei confoimationally consti amed stiuctuies

A particulaily usciul polypeptide denvatn e includes modification to mcoi poiate desuable functional chaiacteπstics using the methods disclosed heiem Such modifications include the mcorpoiation of a label 01 tag, paiticulaily labels 01 tags that may include isotopic substitution, useful foi MS analysis

As used hei em the teim "nucleic acid" when used in icfcience to a component of a biochemical system, is intended to mean tw o 01 moie nucleotides co\ alcntly bonded togethei such as deoxyiibonucleic acid (DNA) 01 iibonucleic acids (RNA) and including, foi example, smgle-sti anded and a double-stianded nucleic acid The teim is similaily intended to include, foi example, genomic DNA, cDNA, mRNA and synthetic oligonucleotides coπespondmg theieto which can iepiesent the sense stiand, the anti- sense stiand 01 both

As used heiein, a "functional gioup" is any chemical gioup that has desiiable functional piopeities A desuable functional piopeity is any piopeity that impaits a desiiable chemical chaiacteiistic to a molecule A functional gioup can include a gioup that changes the physicochemical piopeities of a molecule, foi example, changing the mass, chaige, hydiophobicity, and the like A paiticulaily useful functional gioup is a label 01 tag, foi example, fluoiophoies, chiomophoies, spin labels, isotope distiibution tags, and the like

The teim "non-volatile salts", as used heiem, iefeis to salts piesent in the mobile phase which aie substantially non-volatile undei conditions used foi lemoving mobile phase solvents when interfacing a liquid chiomatogiaphy system with a mass spectiometei Thus, salts such as sodium chloiide 01 potassium phosphate aie consideied non-volatile salts, wheieas salts such as ammonium foi mate, ammonium bicaibonate, 01 ammonium acetate, which aie laigely lemoved undei vacuum, aie volatile salts Othei volatile salts can be used, as will be appaient to one of oidinaiy skill in the ait Foi example, ammonium (NH₄ ^") salts of volatile acids (e g , foimic acid, acetic acid, tiifluoioacetic acid peifluoiooctanoic acid) aie geneially \ olatilc salts suitable toi use \\ ith MS detection

The teim "pH is ait-iecognized, and ieieis to a measuie of the acidity 01 alkalinity oi a compound in aqueous solution Win Ic the pH of a compound in oiganic solvents may not be identical to the pH in aqueous solution, the term "pH" is used in iefeience to both aqueous and oiganic solutions unless otheiwise stated The pH can be detei mined by mcasunng the concentiation of hydiogcn ions 01 pioton potential in solution

The tcim "obtaining" as in obtaining a matciial, component 01 substance is intended to include buying, synthesizing 01 otheiw ise acquning the matenal, component oi substance

Membianes

In one aspect, the invention is diiected towaids a membiane compiismg an ionic bianch polymei and at least one othei polymei

In one embodiment, the invention piovides foi a membiane wheiein the bianch polymei and the othei polymei foim a polymei blend

In ceitain embodiments, the membiane is a poious membiane

In vaπous embodiments the invention pi o\ ides foi a membiane wheiein the ionic bianch polymei is selected fiom dendnmeis, aiboiols, polycations, polyanions, and polyamphiphiles In certain embodiments, the dendnmei is polethylemmme (PEI), dextiansulfate, polyomithme, polyaiginme, poly(L-seime estei), poly(L-lysine), poly(D- seime estei), poly(D-lysine), poly(diallyldimethylammonium chloiide) (PDDA), 01 poly(allylamine) hydiochloiide In one embodiment, the dendnmei is polethylemmme (PEI), dextiansulfate, 01 polyvmyhmidazole

In anothei embodiment, the invention piovides foi a membiane wheiem the othei polymei is selected fiom nitiocellulose (NC), polysulfone (PU), polyetheisulfone (PES), polyamide (PAM), polyvmylidene difluoiide (PVDF), vmylidene fluoiide (VDF), polyethylene (PE), polypiopylene (PP), polystyiene (PS), polyolefms, polyethylene, cellulose acetate (CA), polycaibonates (PC), polyestei substiates, Polyethylene Teiephthalate (PET) Polybutylene Teiephthalate (PBT), polyvinyl fluoiide (PVF), polytetiafluoioethylene ( PTFE) fluoi mated ethylene pi opylenc (FEP), Polyetheiethei ketone (PEEK) Polyctheiimide (PEI) Polymcthylpentene (PMP) Polyphylene Oxide (PPO), Polyphenylene Sulfide (PPS), Polyunyl Chloiide (PVC), PolyStyi ene-Aciylonitπle (SAN), HFP, polyimide, PTFE Polyaciylonitiile, Polyethenmide, Polyamidc-imide, Aiomatic polyamide, and copolymeis theieot

In ceitain instances, examples ol polymcis of the invention can include any oiganic monomeis that can cause cham-giow th polymenzation using iadicals cations and anions as lmtiatois, such as ethylene, 1 -alkyl olefins, 1 ,3-dicnes, styiene methyl styiene, halogenated olefins, \ inyl estei , aci ylates, methaci ylates aciylomti ile, methaciylonitπle, aci ylamide methaciylamide, \ inyl etheis, N-vinyl caibazole, N-\ inyl pyiiohdone, aldehydes, ketones, etc Othei oiganic monomeis whose polymenzation method is know n can be acenaphthalene, ethyl \ inyl ethei, piopene, n-butyl vinyl ethei, i- butyl vinyl ethei , p-methoxystyiene, isobutylene, allyl acetate, vinyl acetate, p- biomostyiene, allyl chloiide, isopiene, 2-vinylpyiidine, vinyl chloiide, m-nitiostyiene, vmyhdcne chloiide, methyl methaciylate, methaciyhc acid, methyl aciylate, vinyl fluoπde, n-butyl aciylate, aciylic acid, 1 -hexene, methyl vinyl ketone, diethyl, maleate, tetiafluoioethylene, o-cliloiostyiene, diethyl fumaiate, fumaionitnle, maleic anhydnde, etc The oiganic monomeis can be conti oiled withm less than 100% by weight depending on distiibution and amount of the ionic dendnmei, and can be selected in the iange depending on desned piopeities by those skilled in the art

In certain embodiments, the othei polymei is selected fiom nitiocellulose (NC), polysullone (PU), polyetheisulfone (PES), polyamide (PAM), polyvmylidene difluoiide (PVDF), polyethylene (PE), polypi opylene (PP), polystyiene (PS), and cellulose acetate (CA) In one embodiment, the othei polymei is nitiocellulose

In anothei embodiment, the invention piovides a membiane wherein the ionic blanch polymei compiises about 0 001% to about 5 0% of the membiane In certain embodiments, the ionic blanch polymei compiises about 0 01% to about 2 0% of the membiane In a fuithei embodiment, the ionic blanch polymei compiises about 0 01 % to about 1 0% of the membiane In anothei embodiment, the invention pio\ ides a membi ane w het em the othei polymei composes about 5% to about 20% of the membiane In a fuithet embodiment, the othei polymei compiises about 8% to about 1 1% ot the membiane

In ceitam embodiments, the inv ention piov idcs a membiane disclosed abov e luithei compiising one oi mote oiganic solvents In ceitam embodiments, the oiganic solv ents aie selected fiom acetone, ethyl acetate, methyl acetate, he\ane, methanol, ethanol, isopiopanol, butanol, toluene, loimamide, polyethylene glycol (PEG), Polypi opylcne Glycol( PPEG) Tπethylene Glycol (TEG) polyethylene oxide (PEO), polyaciylates (PAA), dimethyl foimamidc (DMF), dimethyl sulfoxide (DMSO), N N- dimethyl acetamidc (DMAC), methyl ethyl ketone, dichloiomethane, and l-methyl-2- pyiiohdmone (NMP), Tiiethyl Phosphate (TEP) Poly(aciylamide (PAM), Dibasic Estheis (DBE) Dichloiomethane, and Hexane In ceitam embodiments, the solv ents aie selected fiom acetone, isopiopanol, and butanol

In one embodiment, the one ot moie oiganic solvents compiise about 30% to about 90% ot the membiane In a fuithei embodiment, the one oi moie oiganic solvents compπse about 50% to about 80% of the membiane

In vatious embodiments, the invention ptovides a membiane furthet compπsmg one ot mote suifactants Such suifactants aie selected fiom sodium dodecyl sulfate (SDS), Neodol, Teigttol, Pluionic, alkyl ethei sulphates, acyl lactylates, acyl methyl tautates, acyl lsethionates, alkyl sulphates, acyl saicosmates, alkyl sulphosuccmates, alkyl ethei sulphosuccmates and Polyethoxilates In a furthet embodiment, the suifactant is sodium dodecyl sulfate (SDS)

In one embodiment, the suiiactant compiises about 2% to about 10% of the membtane In a fuithei embodiment, the suifactant compiises about 5% to about 8%o of the membi ane

In anothei embodiment, the invention piovtdes a poious membtane whet em the poious membiane has a thickness iangmg between about 1 μm to about 1000 μm In ceitam embodiments, the membiane has a thickness iangmg between about 1 μm to about 500 μm In certain embodiments, the membiane has a thickness iangmg between about 25 μm to about 250 μm In anothei embodiment, the membiane thickness ianges fiom about 100 μm to about 700 μm In certain embodiments, the membiane has a

10 thickness ianging betw een about 300 μm to about 600 μm It is a fuithei object of the piesent im ention to piovide a composite mcmbiane ot contiolled thickness and sui face

In still anothei embodiment, the im ention pio\ ides a poious membi ane w heiem the poious membi ane compiises poies ianging in size fiom about 0 01 to about 14 μm In cci tain embodiments, the poies iange in size horn about 0 1 to about 2 0 μm In cei tain embodiments the poies iange in size fi om about 1 0 to about 10 0 μm

In one embodiment, the im ention pio\ ides a poious membi ane w hcicin the poies compiisc about 5-85% of the membiane sui face In anothei embodiment the poies compiisc about 5 25% of the membi ane sui face In anothei embodiment the poies compπse about 15-50% of the membiane suiface In anothei embodiment the poies compiise about 50-75% of the membiane suiface

In ceitain embodiments, the invention pio\ ides a poious membiane whei ein the membiane has a poie density ianging fiom about 10,000 to about 60,000,000 pei cm² In anothei embodiment, the poie density ianges fiom about 25,000 to about 100,000 pei cm² In anothei embodiment, the poi e density ianges fiom about 75,000 to about 500,000 pei cm²

In anothei embodiment, the invention piovides a membi ane which is utilized as a cast oi a coating In ceitain embodiments, the membiane is a coating of solid substiates, poious substiates, oi semi-poious substiates In a fuithei embodiment, the substiate consists of a shape selected fiom a plate, a panel and a tube In anothei fuithei embodiment, the plate oi panel is a micio plate oi micio panel

In ceitain embodiments, the micio plate oi micio panel consists of non-woven mateπals, glass, Polycaibonate, Polyestei , PVDF, PES, PS, PP, PE, oi CAB In othei embodiments, the tube consists of none-woven matenals, glass, Polycaibonate, Polyestei , PVDF, PES, PS, PP, PE, oi CAB In a fuithei embodiment, the tube has an inside diametei ianging fiom 1 mm to about 500 mm, and an outside diametei ianging fiom about 2 0 mm to about 900 mm In ceitain embodiments, the tube has an inside diametei iangmg fiom 2 mm to about 250 mm, and an outside diametei ianging fiom about 3 5 mm to about 500 mm

The membiane of the invention exhibits impioved suiface adhesion piopeities when coated on to solid, poious, and semi-poious substiates of geometiic shapes, iangmg

1 1 from standaid non-\\ o\ cn matcπals, glass micio-plates 01 panels, Polycaibonate micio- plates oi panels, Polyestei micio-plates PVDF micio-plates 01 panels, PES micio-plates oi panels, PS micio-plates 01 panels, PP micio-plates 01 panels, PE micio-plates 01 panels, CAB rnicio- plates 01 panels, and othei shapes in tube foim made horn the listed polymcis on sizes ianging horn veiy small hollow fibeis (2mm inside diametei \ λ S mm outside diametei ) to laigci tube sizes up to (250 mm ID \ vaiious Outside diametei s and wall thickness

It w as surpiisingly found that PEI, aftei a suitable blending piocess, can be dispeised in a polymei, such as nitiocellulose Moieo\ ei , depending on the chaiacteiisitics of the desned matenal and on the conditions used, it is possible to obtain membianes dispeised w ith solvents and suifactants

In anothei aspect, the invention pio\ ides a membiane compiising polyethylemmine, nitiocellulose, an oiganic solvent, and a suifactant In one embodiment, the polyethylemmine compiises about 0 01% to about 2 0% of the membiane In anothei embodiment, the nitiocellulose compiises about 8% to about 1 1% of the membiane In ceitain embodiments, the oiganic solvent compiises about 50% to about 80% of the membiane In othei embodiments, the suifactant compiises about 5 0% to about 8 0% of the membiane

In anothei aspect, the invention piovides a membiane compiismg dextian sulfate, nitiocellulose, an oiganic solvent, and a suifactant In one embodiment, the dextian sulfate compiises about 0 05% to about 5 0% of the membiane

The composite membianes of the invention can be used foi a vanety of applications, including but not limited to, piotem binding studies, liquid fϊlttation and sepaiations, gas particle sepaiations, and suiface ietention of selected species

The mcoipoiation of small amounts of a dendnmei , such as PEI, into a polymei such as nitiocellulose, have measuiable effects iegatding membiane binding capacity, membiane sui face adhesion piomotion, membiane poious structuie, and symmeti y oπentation Specific advantages of the membianes of the invention include the foimation of miciopoious membianes with enhanced piotem suiface binding capacity, impioved adhesion piopeities betw een the membianes and vaiious supports oi substiates, and membianes that aie less buttle than conventional non-composite membi anes Membiane

12 sin face binding capacity is influenced by se\ eial factois and distinctiv e chaiacteiistics of iespectn e application, including but not limited to, pi otem species, affinity 01 suiface chaige ielationships between suifaces, i ecipient suiface and applied constituents, membiane suiface thickness, poie size, suiface poie density, and sui face symmetiic oiientation

Specifically, the suiface piotein binding capacity is a function of total piotem applied to a suiface, minus piotem ictamed m a suiface which equals the peicentage of the total pi otein bound Thus, the gieatei the suiface ietention the highci the binding capacity The membianes of the in\ ention have at least t\\ ice the binding capacity of othei com entional membianes, iesultmg in pei foimance ad\ antages w hich ieduce matenal costs from substantially less amounts of piotems applied 01 consumed

Sti Lictui al advantages of the composite membianes, when used on suppoits 01 substiates, includes inci eased adhesion to a suppoit 01 substiate, pioduction cost i eduction due to elimination of a pie-coat piepaiation, impioved membiane suiface delaminatmg, mci eased iesistance to back piessme m filtiation opeiations, and gieatei membi ane suiface flexibility

Othei advantages of the composite membianes of the invention include mci eased blotting, piotem sequencing, and impioved chemilluminscence detection and binding

Geneially, ciosslmkmg agents, imtiatois and suitable amounts of solvents can be lequned m polymeiizmg the oiganic monomeis These components aie all known to the ait to which the piesent invention belongs Di- 01 poly-alcohols, amines, and vinyl gioup deπvatives, etc can be used as the ciosslmkmg agents The ciosslmkmg agents suitable foi the piesent invention can be 1 ,2-ethanedioldiaciylate, 1 ,3-piopandioldiaciylate, 1 ,3- butanedioldiaciylate, 1,4-butanedioldiaciylate, 1 ,5-pentanedioldiaciylate, 1,6-hexane dioldiaciylate, divinyl benzene, ethyl eneglycoldiaciylatc, piopyleneglycoldiaciylate, butyleneglycoldiaciylate, tπethyleneglycoldiaciylate, polyethyleneglycoldiaciylate, polypi opyleneglycoldiaciylate, polybutyleneglycoldiaci ylate, allyl aciylate, 1 ,2- ethanedioldimethaciylate, 1 ,3-piopandioldimethaciylate, 1 ,3-butanedioldimethaciylate, 1 ,4-butanedioldimethaciylate, 1 ,5-pentanedioldimethaciylate, 1 ,6-hexanediol dimethaci ylate, ethyleneglycoldimethaciylate, piopyleneglycoldimethaciylate, butyleneglycoldimethaciylate, tπ ethyleneglycoldimethaciylate, polyethylene

13 glycoldimethaciylate, polypi opylcncglycoldimcthaciylalc, polybutylcncglycol dimethaciylate allyl methaciylate and diallyl maleate

The initiatois include, but aie not limited to azobisisobutyionitnle benzoyl pcioxide, acetyl peioxide, lauiyl peioxide, t-butyl pei acetate cumyl pei oxide, t-butyl peioxide, t-butyl hydiopeioxide, and potassium pei sulfate

The polymenzation can be earned out at the tempciatuie ianging Ii om about 0 ⁰C to about 100 ⁰C, in ceitain embodiments fiom about 25 ⁰C to about 200 ⁰C, in ceitam embodiments horn about 25 ⁰C to about 100 ⁰C, in ceitam embodiments iiom about 100 ⁰C to about 200 ⁰C Reaction times iange fiom about 1 houi to a few days, in ceitam embodiments ieaction times iange fiom about 3 houis to about 24 houis, in ceitam embodiments ieaction times iange fiom about 3 houis to about 12 houis, in ceitam embodiments ieaction times iange fiom about 12 houis to about 72 houis. in ceitam embodiments ieaction times iange fiom about 12 houis to about 48 houis

The PEI composite mcmbiane may be piepaied by a pioceduic which permits mteifacial teaction between the exposed sin face of the PEI film and a suitable polyfunctional agent Examples of such pioceduies include casting a solution of PEI on the mtiocellulose membiane, dipping oi immeising the suppoit m solution, etc (The most piactical and useful solvent foi the PEI is watei) Geneially, howevei, formation of the film is most conveniently and effectively piepaied by simply placing the mtiocellulose in the PEI solution foi a penod of time sufficient to peimit adsorption of a film of the solution onto the suppoit Geneially, the penod of contact is not ciitical, penods of a few seconds to 24 houis can pioduce good membianes

The composite membiane of the invention is then piepaied by ieaction of the sui face of PEI film with the polyfunctional ieagent This ieagent consists of a difunctional oi tiifunctional oiganic compound, oi an aggiegate of monofunctional monomeis, i e , a compound containing two oi thiee functional gioups capable of ieacting with amine gioups in the PEI Since the puipose of the polyfunctional ieagent is to piovide an mteifacial ieaction substantially concentiated on oi confined to the suiface of the PEI film, the polyfunctional ieagent should be selected in accoi dance with the piinciples of mteifacial ieactions Foi example, when the PEI film is cast fiom an aqueous solution, the polyfunctional ieagent oi polyfunctional ieagent solution should be

14 substantially insoluble in w atei Foi this and othet ieasons \ aπous polyfunctional ieagents compatible v\ ith non-polai oiganic (e g hydiocaibon) soh ents but substantially insoluble in watei aie pieteπed All watei-insoluble hydiocaibon soluble polyfunctional agents do not wotk w ith equal effectiv eness, and agents having isocyanate 01 acid chloπde (e g , caiboxyhc acid chloπde 01 sulfonyl chloiide 01 cyanuiic acid chloiide i c cyanui ic chloiide) functional gioups aie piefeπed Selection ot the polyfunctional ieagent is also governed by empiiical consideiations e g the salt lejection and flux piopcities oi iesistancc to compaction of the ultimately obtained combination ot the suppoit film the PEI film, and the suiface coating 01 bauiei layei pioduced by the ieaction at the inteiface betw een the polyfunctional ieagent medium and the exposed suiface of the PEI film

Reaction of the PEI film with the polyfunctional ieagent is conveniently accomplished by unmeision of the film in a soh ent solution of the ieagent The soh ent employed must not dissolve eithei the PEI 01 the suppoit matenal Hydiocaibon solvents such as n-hexane, heptane, octane, 01 cyclohexane aie geneially most piactical Optimum concentiation of the polyfunctional ieagent m the solvent may vaiy consideiably depending on the specific ieagent, solvent, suppoit, etc , and is best determined expenmentally Howevei concentiations of about 0 1 to 5 0, piefeiably about 0 5 to 1 0 peicent aie geneially satisfactoiy

The intei facial ieaction between the suiface of the PEI film and the polyfunctional agent can occui at loom tempeiatuie, particulaily m the case of the loscyanate/amine ieaction, which iesults in uiea linkages Since this mteifacial ieaction is laigely concentiated on the suiface of the PEI film and does not necessaiily i educe the watei sensitivity of internal iegions of the PEI film, it is piefeπed to autogenously ciosslink the PEI film with heat, e g , at a tempeiatuie of about 90 ⁰C-130 ⁰C This heat-activated cioss-lmkmg typically involves mteiactions between terminal oi pendant amine (e g , pnmaiy amine) gioups of the PEI and hbeiation of ammonia The iesult of the autogenous cioss-lmkmg is msolubilization of the PEI Othei methods foi msolubilizmg PEI film are known, but, if used m the context of this invention, these othei methods should not mteifeie with the mteifacial cioss-lmkmg ieaction oi the formation of a salt bauiei layei on the suiface of the PEI film The PEI msolubilizmg ieaction conditions

15 aic selected Io attain adequate msolubihzation w ithout undue saciificc of flux piopeities Inadequate msolubihzation allow s the PEI film to ictain sufficient \\ atei sensitn ity to be e\cessi\ ely s\\ elled by w atei causing the o\ eiall membi anc composite to be less duiable

The mteifacial cioss-hnkmg and msolubihzation ieactions can be earned out simultaneously in the soh ent solution (one step piocess) in w hich case the soh ent solution is heated to the l equπ ed tempeiatuie Oi , pieleiably, the PEI film can be lemoved aftei a shoit pci iod e g , about 10 seconds to 10 minutes, and placed in an o\ en at the lequn ed tempeiatuie to can y out the msolubihzation (tw o-step piocess) Optimum i eaction time may also \ ai y w ith the above-discussed \ auables but a peπod of about S to 30 minutes is usually satisfactoiy

Diying of the PEI film, to lemove fice w atei pπoi to ieaction w ith the polyfunctional ieagent is necessaty if the lattei is ieadily hydiolyzed by w atei Aii -di ymg is usually satisfactoiy, but application of heat, as by means of iadiant gas heateis oi infiaied lamps, may be employed to acceleiate di ymg Howevei, diymg can be omitted if the polyfunctional ieagent has a manifold gieatei leactivity towaid the PEI veisus watei oi is of a type that is not ieadily hydiolyzed by watei Foi example, veiy good iesults (see examples) have been obtained by ieaction of a low moleculai weight PEI (moleculai weight, 12,000) on a polysulfone suppoit film with tolylene dnsocyanate, without the use of a diymg step When di ying a PEI-coated polysulfone suppoit, heat is applied to the back of the polysulfone film so that watei vapois escape thiough the coaise poies in the back of the film and, theicfoie, do not distuib the PEI layei on the face of the film

Optimum iesults aie usually achieved by means of in situ formation of the membiane on the suppoit Accoiding to this pioceduie, the PEI film is initially adsoibed on the suppoit matenal by contacting the suppoit with an aqueous solution of the PEI, as described above Since PEI is a catiomc polyelectiolyte that is ieadily adsoibed on poious matenals, it is particulaily suited to in situ formation of membianes on poious suppoit mateiials, such as nitiocellulose

The adsoibed PEI on the suppoit is then ieacted with the polyfunctional ieagent, as desciibed above, icsiilting in the in situ formation of the baπiei membi ane on the adsoibed PEI Again, PEI is uniquely effective in its high degiee of ieactiuty with the polyfunctional l eagents, as well as the above-mentioned outstanding ability to be

16 adsoibcd

By employing a film-foiming polymei haung a piuiality of icactn e ammo 01 hydioxyl gioups, foi example, 01 a mtiocellulose polymei, and by tieating this polymei with a monomei which will cioss-lmk the polymei iathei than ieact w ith two gioups on the same molecule, ultiathm films can be cicatcd w hich aie composite membianes In this lespect, paiticulaily good piopeities aie displayed by ultiathin films cieated ftom a fan Iy highly blanched polyamme, i e one ha\ ing a substantial peicentage at least about 1 5 peicent, of its ammo gioups picsent as bl anches to the mam chain of the molecule e g polyethylcmmme (PEI) Ho\\ e\ ei, the ammo gioups constituting these bianch chains aie usually piimaiy ammo gioups and as a iesult w hen the cioss-hnking ieaction takes place, these piimaiy ammo gioups foim secondai y amides, sulfonamides, oi the like, depending upon the paiticulai ieaction Although vanous piopeities may be initially exhibited, when such ultiathm membianes aie used with a chloime-tieated feed, degiadation of these piopeities occuis It is believed that the hydiogen atom attached to the secondaiy amido gioup is subject to oxidation attack by the hypochloiite ion and that this attack iesults in the giadual opening up of the otherwise tight, cioss-lmked moleculai stiuctuie of the ultiathm film to an extent wheie its piopeities begins to deciease Moieovei, these secondaiy amido sites aie hydiophilic and aie consideied to attiact heavy metal ions and to be conducive to complexing If a polymei such as polyvinyl alcohol is used, the unieacted hydioxyl sites aie consideied to function similaily

It has been found that, by ti eatmg the polyamme, e g , PEI, with a suitable ieactant that will minimize the numbei of secondaiy amido gioups m the ultimate membiane, forming a membiane that is substantially moie iesistant degiadation Tins giaftmg ieaction can be earned out eithei befoie oi attei the polyamme is cioss-lmked If the ieaction occuis befoie cioss-linkmg, a ieactant is used that is highly selective to ieact only with the pπmaiy ammo gioup and change it to a secondaiy ammo gioup The piefened addition ieactant is aciylonitiile, which iesults in the cyanoethylation of the piimaiy ammo bianch chains How evei , othei ethylene compounds which aie leactive w ith piimaiy amines can also be used, as well as epoxides, aldehydes and anhydπdes, ioi example, phthahc anhydnde Polyfunctional amines, heated in this mannei, form ultiathm films that aie iesistant to oxidation

17 The mcmbiane 01 film can be foimed in situ upon a miciopoious substiate 01 it can be foimed sepaiately, as by a floatation-deposition method Foi in situ formation, the poies in the suiface of the miciopoious substiate aie piefeiably sized between about IOOA and about 100OA, howe\ ei, depending upon the cπcumstanccs of the foimulation and the use of the composite mcmbiane suiface poies ianging in size betw een about 5OA and about 5000A may be acceptable U S Pat No 3,676,203, the disclosuie of which is incoipoiatcd heiein by lefcience, indicates that \ anous commeicially a\ ailable mateπals, such as Millipoic filteis (types VS and VM) may be used as poious substiates in making composite membianes This patent also indicates that suitable poious substiates may be cast tiom homopolymeis 01 fiom mixed polymeis of cellulose acetate (CA), polysulfone, cellulose butyiate, cellulose nitiate (CN), polystyiene and the like, and it desciibes a casting piocess foi making suitable miciopoious substiates fiom a CA-CN mixtuie In piefeited embodiments, the substiate polymei is nitiocellulose

The piefeπcd polyamme is polyethylemmme having a moleculai weight between about 40,000 and 100,000, which is watei -soluble, howevei, othei polyethylemmmes having moleculai weights in the iange between about 2,000 and about 100,000 may also be employed Polyethylemmme is pioduced by polymei lzation of ethylemmine and has pieviously had a wide vanety of commeicial applications such as adhesives, flocculating agents, ion exchange lesms, complexing agents, absoibents, etc It is a highly blanched polyamme with ammo nitiogens in the iatio of pπmaiy secondaiy teitiaiy of about 1 2 1 The moleculai weight of the PEI is not a ciitical factoi m the inv ention, although optimum values may vaiy depending on vaπous factois such as the type of suppoit, natuie of the salme watei feed, salt i ejection, and flux desned, etc Geneially, a moleculai weight of about 600 to 100,000 is suitable As pieviously indicated, the polyethylemmme piefeiably also has at least about 15 peicent of its aminoethylcne moieties piesent as blanches to the mam chain of the molecule Polyethylemmme is commeicially available in highly blanched form and in a vanety of moleculai weights as a pioduct of the polymei ization of ethylemmine

If an mteifacial condensation ieaction is used, the ieactants may be dissolved m solvents that aie substantially immiscible with each othei Polyethylemmme and polyvinylalcohol aie watei -soluble and can advantageously be employed m aqueous solution Instead of using inteitdcial condensation, the monomei may be applied dii ectly, c g , possibly in the \ apoi phase 01 as a solution in a soh ent irascible \\ ith w atei, such as dioxane 01 tetiahydiofuian, ho\\ e\ ci, most consistent iesults ha\ e been obtained by applying the diacyl halide dissoh cd m an oiganic caiiici that is substantially immiscible \\ ith w atei as a pait of an mteifacial condensation i eaction

When polyethylenimine is used, it may fust be ieacted w ith an appiopnate amount of aciylonitiile undei conditions w hich assuie cyanoethylation oi substantially all of the pnmai y amino gioups 01 the polyethylenimine may fust be cioss-lmked and then ieacted w ith aciyloniti ile 01 a suitable icactant This is a standaid giaft polymenzation ieaction and is earned out undei know n conditions Once the ieaction begins it pioceeds exotheimically If the ieaction is earned out initially, the i esultant giaft polymei is also watei soluble, and the cioss-hnkmg ieaction is earned out m the usual mannei A sufficient amount of aciylonitiile should be piovided to ieact with the calculated amount of pnmaiy ammo gioups piesent in the polymei, and geneially a slight excess of aciylonitiile is piovided to assuie that substantially all of the pnmaiy ammo gioups have been cyano ethyl ated

Aftei the cyanoethylation is complete, an appiopnate watei solution of the gi aft polymei, foi example, appioximately 2 peicent, is piepaied, and a miciopoious substiate is soaked m this solution foi a sufficient penod of time that it penetiates theiethiough, foi example, about 15 minutes The miciopoious substiate is then lemoved, diamed and appiopi lately an-diied in a ciiculatmg-an oven, e g , foi about 30 minutes Theieaftei, the dned miciopoious substiate is again biiefly immeised into the aqueous solution, diamed and then tieated with the monomei, as foi example by dipping into a suitable solution oi by coating theiewith

The ieaction of the polyamine with the diacyl halide, oi some othei monomei, is allowed to pioceed foi an appiopnate penod of time to assuie that cioss-hnking to the extent desnable is achieved Two vanables which play a majoi iole in deteimimng the thickness of the i esultant ultiathm film in an mteifacial condensation ieaction aie the concentiation of the monomei at the mteiface and the time inteival of contact between the oi game phase and the aqueous phase Foi example, when isophthaloyl chlonde is employed in an mteifacial condensation ieaction to pioduce a polyamide membiane, a

19 0 4 to 0 8 weight peicent solution in hexane may be used Using solutions of these apptoximate weight peiccntages, the time of tieatment w ill genei ally be about 15 seconds It should be undei stood that time is appiopi iately adjusted depending upon the w eight peiccntages, inasmuch as the paiameteis oi time and concentiation ai e co- \ di iable

WIi en a film-foiming polymei such as nitiocellulose, is used w hich has i eactn e gi oups of all the same type the giaft ieaction is piefeiably earned out aftci cioss-hnkmg so as to lemove the potentially l eactive sites pio\ ided by the unieacted functional gioups Cioss-hnkmg may be achie\ ed using know n di- oi ti i- functional monomei s, foi example, di- oi tiiacyl hahdes, diisocyanates and difunctional ieactn e ethylene compounds, such as dicyanobutadiene Any suitable ieactant that will ieact with the hydioxyl gioups may be used, ioi example, an acid hahde, an isocyanate, oi an epoxide

A vanety of membiane shapes aie commeicially a\ ailable and useful in the piesent invention These include spnal wound, hollow fibei, tubulai, oi flat sheet type membi anes

The membianes of the piesent invention may be subjected to various post tieatments as desciibed m U S Pat Nos 4,765,897, 5,876,602 and 5,755,964, all of which aie mcorpoi ated heiein by iefeience Such post tieatments may fuithei enhance membiane peifoπnance

Foi example, as desciibed in U S Pat No 5,876,602, membiane stability to sti ong base exposuie can be achieved by contacting the membiane, whethei in flat sheet

01 element foim, with a hypochloiite solution at a pH of at least 10 5 The optimal exposuie time depends on the tempeiatuie and concentiation of the hypochloiite used At loom tempeiatuie, conditions which achieve the stated goals can geneially be found withm the ianges of 10 minutes to 5 houis and at concenti ations of 200 to f 0,000 ppm by weight of hypochloiite, measuied as chloiine Piefeπ ed concentiations of hypochloiite aie 500 to 7,000 ppm, piefened exposuie times aie 30 minutes to thiec houis In a piefeπed embodiment the membiane is subjected to a heat tieatment befoie being exposed to the afoiementioned chlorine tieatment The membianes aie heated in watei at a tempeiatuie of 40 ⁰C to 100⁰C foi times of 30 seconds to 24 houis The heat tieatment iesults in a fuithei loweπng of the salt passage and the lemoval of impuiities contained in

20 the mcmbi ane which otheiw ise may mtei ieie in the beneficial iesults of the chloiinc ticdtment

Anothei example of an applicable post tieatment is descπbcd in U S Pat No 5,755 964, w hich compiises contacting one layei of the polymei with an amine fiom the gioup consisting of ammonia optionally substituted w ith one oi moie alkyl gioups of one to tw o caibons which alkyl gioups may be fuithei optionally substituted w ith one oi moie substituents selected horn hydio\y, phenyl, oi ammo, butylamme, cyclohexylamme, 1 ,6- hexanediamme and mixtuies theieof Piefeπ ed substituted ammonia substances include those such as dimethylamme, tnmcthylamme, ethylamme, tnethanolamme, N, N- dimethyl ethanolamme, ethylenediamine, and benzylamme It has been discoveied that by contacting the above amines with the polymei, the flux is inci eased and the i ejection iates fot patticulai substances may be changed The degi ee that the flux of the membiane is incieased oi enhanced may be contiolled by vaiymg the paiticulai amine employed, the concentiation of the amine, the time of contact between the discriminating layei and amine, the tempeiatuie of the contact, the pH of the amine solution, oi combinations theieof "Flux" is the flow iate pei unit aiea at which solvent, typically watei, passes thiough the membiane

The amine used to tteat the polyamide discnmmatmg layei may be in solution, neat, oi even a gas phase so long as it can be contacted with the polyamide Gas phases may typically be employed foi lowei moleculai weight amines such as ammonia, methylamine, and dimethylamme The solvent may be any solvent m which the amine is soluble so long as the flux enhancement and the peifoimance of the membiane is not hmdeied by contact with the solvent Typical solvents may include watei and oiganic compounds such as alcohols and hydiocaibons piovided the suppoit is not dissolved by the solvent Geneially, because of its ease of handling and its availability, watei is employed if a solvent is desned

The pH of the amine solution to be contacted with the polymei is not a ciitical aspect of the invention Howevei, the pH should not be so low that the paiticulai amine being employed piecipitates out of solution On the othei hand, the pH should not be so high that the polymei is degiaded oi peifoimance is negated Piefeiably, a pH of about 7 to about 12 is useful m the method of the pi esent invention and foi some amines highei

21 pHs may mctease the degi ee of flux enhancement

Additional membiane modification can be achie\ ed by post ti eating the subject membianes by contacting the membianes w ith a stiong mineial acid, e g , phosphoiic acid, polyphosphoiic acid, phosphoious acid, sulfuiic acid, etc Phosphoiic acid at concenti ations of fiom about 10 to about 85 w eight peicent aie pai ticulai ly pi eteiied As desci ibed m U S Pat No 4,765,987, the membiane may be contacted w ith the mineial acid, e g , by spiaying an aqueous acid solution onto the membi ane, dipping the membiane in an aqueous acid bath, etc In some embodiments the acid solution may be heated Once tieated with the mineial acid, the membiane may be fuithei tieated w ith the i ejection enhancing agents, e g , colloids, tannic acid, polyamidoammes etc, as descubed in U S Pat No 4,765,897

Methods of the invention

In one aspect, the invention piovides a method foi binding a taiget molecule, compiising contacting the taiget molecule with a poious membiane compnsmg an ionic bianch polymei and at least one othei polymei, and detecting whethei binding has occuπed between the membi ane and the taiget compound, wheiein the membiane compiises a pluiahty of poies, and wheiein the poies bind to a taiget molecule

In one embodiment, the membi ane binds taiget compounds consisting of small molecules, maciomolecules, pai tides and ccllulai systems In a fuithei embodiment, the taiget compounds aie selected fiom the gioup consisting of nucleic acids, piotems and hgands

In ceitain embodiments, the taiget compounds bind to the poious membiane at a poie sin face

In vaπous embodiments, the taiget compounds aie pioteins In a fuithei embodiment, said taiget compounds aie oligopeptides oi polypeptides

In anothei embodiment, the taiget compounds aie nucleic acids In a fuithei embodiment, the taiget compounds aie DNA, oligonucleotides oi polynucleotides

22 In one embodiment, the taiget compounds bind to the mcmbiane at about 20% to about 75% ot the total taiget compounds applied to the membiane In a fuithci embodiment, the taiget compounds bind to the membiane at about 40% to about 60% ol the total taiget compounds applied to the membiane

In ceitam embodiments, the invention pi ox ides a method foi binding a taiget molecule, compiising contacting the taiget molecule w ith a poious membiane composing an ionic blanch polymei and at least one othet polymei , and detecting whethei binding has occuiied between the membiane and the taiget compound wheiem the ionic blanch polymei is selected fiom dendπmeis, aiboiols, polycations polyanions and polyamphiphiles Such dendπmeis aie selected tiom polethylemmme (PEI), dextiansulfate, polyomithine, polyaiginine, poly(L-seiine estei), poly(L-lysine), poly(D- seime estei), poly(D-lysine), poly(diallyldimethylammomum chloπde) (PDDA), poly(allylamine) hydiochloiide oi polyvinylimidazole

In othei embodiments, the invention piovides a method foi binding a taiget molecule, compiismg contacting the taiget molecule with a poious membiane compiismg an ionic bianch polymei and at least one othei polymei, and detecting whethei binding has occuπed between the membiane and the taiget compound, wheiem the othei polymei is selected ftom nitiocellulose (NC), polysulfone (PU), polyetheisulfone (PES), polyamide (PAM), polyvmylidene difluoiide (PVDF), vmyhdene fluoiide (VDF), polyethylene (PE), polypi opylene (PP), polystyiene (PS), polyolefms, polyethylene, cellulose acetate (CA), polycaibonates (PC), polyestei substiates, Polyethylene Teiephthalate (PET), Polybutylene Teiephthalate (PBT), polyvinyl fluoiide (PVF), polytetiafluoioethylene (PTFE), fluoi mated ethylene pi opylene (FEP), Polyetheiethei ketone (PEEK), Polyetheπmide (PEI), Polymethylpentene (PMP), Polyphylene Oxide (PPO), Polyphenylene Sulfide (PPS), Polyvinyl Chloiide (PVC), PolyStyiene-Aciylonitiile (SAN), HFP, polyimide, PTFE, Polyaciylonitiile, Polyetheπmide, Polyamide-imide, Aiomatic polyamide, and copolymeis theieof In a lurthei embodiment, the othei polymei is nitiocellulose

In anothei embodiment, the ionic bianch polymei compiises about 0 001%) to about 5 0% ol the membiane In ceitam embodiments, the bianch polymei compiises about 0 01% to about 1 0% ol the membiane In certain embodiments, the bianch

23 polymci compiises about 0 1% to about 1 0% of the membianc In ceilain embodiments, the bianch polymei compiises about 1 0% to about ^ 0% of the membiane In one embodiment, the othei polymei compiises about 5% to about 20% of the membianc

In anothei embodiment, the im ention pi o\ ides a method foi binding a taiget molecule, compiismg contacting the taiget molecule w ith a poious membiane composing an ionic bianch polymei and at least one othei polymei, and detecting whethei binding has occulted between the membiane and the taiget compound wheiein the membiane fuithei compiises one oi moie oiganic soh ents selected fiom acetone ethyl acetate, methyl acetate, hexane, methanol, ethanol, isopiopanol, toluene, ioimamide, polyethylene glycol (PEG), polyethylene oxide (PEO), polyaciylates (PAA) dimethyl foimamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethyl acetamide (DMAC), methyl ethyl ketone, dichloiomethane, and l -methyl-2-pyπolidmone (NMP)

In ceitam embodiments, the one oi moie oiganic solvents compiise about ^0% to about 90% of the membiane

In anothei embodiment, the membiane fuithei compiises one oi mote suifactants Such suifactants aie selected fiom sodium dodecyl sulfate (SDS), Neodol, Teigitol, Pluiomc, alkyl ethei sulphates, acyl lactylates, acyl methyl tauiates, acyl lsethionates, alkyl sulphates, acyl saicosmates, alkyl sulphosuccmales, alkyl ethei sulphosuccinates and Polyethoxilates

In othei embodiments, the suifactant compiises about 2% to about 10% of the membiane

Commeicial applications

Miciopoious membianes of the piesent invention that aie pioduced in accoidance heiewith aie useful m a numbei of mdustnes The poious membianes can be used m a vanety of applications, including, but not limited to, liquid sepaiation piocesses such as miciofiltiation, ultiafiltiation, dialysis, captuie and/oi immobilization of biomolecules (e g , nucleic acids, piotems, polypeptides, peptides, vnuses, cells, and the like), as suifaces foi implantation into the body (e g , as pait of an implantable medical device), oi as suifaces mcoipoiated into diffeient devices Additionally, the membianes can be

24 configuied in a \ anety of foi ms including, but not limited to, flat sheets, hollow fibei s ot tubes, and can be any shape

In one aspect, the im ention piovides a device foi binding at least one taiget molecule, compiising a poious membi ane compiising an ionic bi anch polymei and at least one othei polymei

In one embodiment, the membiane binds taiget compounds consisting ot small molecules, maciomolcculcs, paiticles and cellulai systems In a fuithei embodiment, the taiget compounds at e selected iiom the gioup consisting of nucleic acids, pioteins and ligands

In ceitain embodiments, the taiget compounds bind to the poious membiane at a poie sui face

In one embodiment, the invention piovides a device w heiem said taiget compounds aie pioteins In a fuithei embodiment, the taiget compounds aie oligopeptides 01 polypeptides

In anothei embodiment, the invention piovides a device wheiem said taiget compounds aie nucleic acids In a fuithei embodiment, the taiget compounds aie DNA, oligonucleotides 01 polynucleotides

In one embodiment, the taiget compounds bind to the membiane at about 20% to about 75% of the total taiget compounds applied to the membiane In a fuithei embodiment, the taiget compounds bind to the membiane at about 40% to about 60% of the total taiget compounds applied to the membiane

In anothei embodiment, the invention piovides a device compiising a membiane, wheiem the ionic bianch polymei is selected fiom dendiimeis, aiboiols, polycations, polyanions and polyamphiphiles In certain embodiments, the dendiimei is polethylemmme (PEI), dcxtiansulfate, polyomithme, polyaiginme, poly(L-seime estei), poly(L-lysme), poly(D-seπne estei ), poly(D-lysme), poly(diallyldimethylammomum chloiide) (PDDA), poly(allylamme) hydiochloiide oi polyvinyhmidazole

In anothei embodiment, the invention piovides a device compiising a membiane, wheiem the othei polymei is selected fiom nitiocellulose (NC), polysulfone (PlJ), polyetheisulfone (PES), polyamide (PAM), polyvinyhdene difluoiide (PVDF), vmyhdene fluonde (VDF), polyethylene (PE), polypiopylene (PP), polystyiene (PS),

25 polyolefins, polyethylene, cellulose acetate (CA), polycaibonates (PC), polyestei SLibstiates, Polyethylene Teiephthalate (PET), Polybutylene Tciephthalate (PBT), polyv inyl fluoiide (PVF), polytetiafluoiocthylenc (PTFE), fluounated ethylene piopylene (FEP), Polyetheietheiketone (PEEK), Polyetheiimidc (PEI), Polymethylpentene (PMP), Polyphylene Oxide (PPO), Polyphenylene Sulfide (PPS), Polyv inyl Chloiide (PVC), PolyStyiene-Aciylonitiile (SAN), HFP, polyimide, PTFE, Polyaciylonitnle, Polyetheumide, Polyamide-imide, Aiomatic polyamide, and copolymeis theieoi In a fuithei embodiment, the othei polymei is nitiocellulose

In one embodiment, the ionic blanch polymei compiises about 0 001% to about 5 0% of the membiane In anothei embodiment, the othei polymei compiises about 5% to about 20% oi the membiane

In othei embodiments, the invention piovidcs a de\ ice compiising a membiane, wheiem the membiane fuithei compiises one oi moic oiganic solvents selected fiom acetone, ethyl acetate, methyl acetate, hexane, methanol, ethanol, isopiopanol, toluene, foπnamide, polyethylene glycol (PEG), polyethylene oxide (PEO), polyaciylates (PAA), dimethyl foimamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethyl acetamide (DMAC), methyl ethyl ketone, dichloiomethane, and l-methyl-2-pyiiolidinone (NMP) In ceitain embodiments, the one oi mote oiganic solvents compiise about 30% to about 90% of the membiane

In anothei embodiment, the invention piovides a device compiising a membiane, wheiein the membiane fuithei compiises one oi moie suifactants In ceitam embodiments, the suifactants aie selected fiom sodium dodecyl sulfate (SDS), alkyl ethei sulphates, acyl lactylates, acyl methyl tauiates, acyl lsethionates, alkyl sulphates, acyl saicosinates, alkyl sulphosuccinates, alkyl ethei sulphosuccinates and Polyethoxilates In anothei embodiment, the suifactant compiises about 2% to about 10% of the membiane

In one embodiment, the invention piovides a device compiising a poious membiane, wheiem the poious membiane is effective foi caiiying out an analytical task selected fiom the gioup consisting of sequence analysis by hybπdization, analysis of patterns of gene expiession, immunochemical analysis of piotein mixtuies, epitope mapping, assay of leceptoi-hgand mteiactions and piofilmg of cellulai populations involving binding of molecules to hgands oi ieceptois

26 In anothei embodiment the invention piov ides a dev ice tuithei compπsing a detector foi detection of binding ot the potous tiack etched membiane w ith the taiget compound

In ceitain embodiments, the membianes of the im cntion aie coated onto micioaiiay glass slides foi use m binding othei compounds Conv entional nitiocellulose membiane solution foimulations coated onto micioaπay glass slides hav e a piotem suiface binding capacity in the iange ol about 1 S% to about 18% of the total pi otein applied The membi anes of the im ention hav e inci cased binding capapcity, ianging ftom about 40% to about 60%o of the total piotem applied

Conv entional membianes suffei horn diavv backs include bnttleness and lacking tensile stiength, and ai e thus piecluded horn use in a numbei of applications including small filtei devices The composite membi anes of the invention piovidc lmpiovements to ceitain chaiacteiistics of membianes, such as i educed bnttleness and inci eased tensile stiength and elogation, allowing foi use m v eiy small filtiation devices Such chaiacteiistics aie lequned dm ing the assembly and handling piocess used in filtei element manufactuiing The bioad use of the membianes of the invention in filtiation devices includes high volume filtiation and high volume utilization of the membianes m filtei elements, specifically pleated filtei elements, and other laige membiane filtei devices

A useful industiial application of the piesent membianes is in filtiation systems, especially tangential oi cioss-flow filtiation systems In tangential oi cioss-flow filtiation systems, not all of the liquid volume goes thiough the membiane Some fi action of the filtiate volume can be lemoved and iecycled Tangential flow systems chaiacteiistically use tube-shaped filteis oi caitiidges wheie the flow is moved axially thiough the tube and matenal is ieleased tiansveisely acioss the walls of the tube Tangential flow can be used at lowei piessuies than noimal filtiation and the longevity of the filtei is enhanced in this way Because the flow iates of the membi anes of the pi esent invention aie significantly fastei than those of conventional membianes of equal thickness, tangential flow using the piesent membianes is paiticulaily adv antageous because the time foi pi ocessmg a given volume of sample having a given paiticle concentiation will be much fastei than piocessmg using conventional membianes

27 The miciopoious membianes aie also useful in the chemical food and phaimaceutical industnes Foi instance, one paiticulai use in filtei s \Λ ith poie sizes on the oidei oi about 0 1 μm oi less, is the iemo\ al of \ nuses and laige maciomoleculcs Ii om the fluids being piocessed tlnough the mcmbianc The membiane ol the piesent im ention is w idely applicable to ultiafiltiation thiough miciofiltiation Il the size of pai tides of 90% i ejection becomes less than 0 1 μm the w atei peimeabihty will tend to deciease while if the same size exceeds 1 μm the mechanical stiength ol the hollow fibei membiane w ill often deci ease It is theieloi e desii able that the size of paiticles of 90% i ejection be in a i ange of 0 01 to 1 μm

The dimensions of the poious membianes and modified poies can be appiopiiately selected depending on the method of use such as external pi essui e filti ation oi internal piessuie en dilation filti ation

The matciial of constiuction of the poious suppoit of the composite membi ane is not ciitical to the invention Any poious suppoit that pi o\ ides physical stiength to the disci immatmg layei may be employed, so long as the poie sizes aie sufficiently lai ge to permit the unhindeied passage of permeate but not so laige as to mteifeie w ith the bπdging-ovci of the iesultmg disci immatmg layei Typical suppoit matenals that aie known in the art include cellulose esteis, polysulfones, polyethei sulfones, polyv inyl chloπde, chloi mated polyvinyl chlonde, polyvinylidene fluoπde, polystyienes, polycaibonates, polyimides, polyaciylomtiiles, and polyesteis Piepaiation of such supports aie desciibed in U S Pat Nos 3,926,798, 4,039,440, and 4,277,344, all of which ai e mcorpoi ated heiem by iefeience The thickness of the miciopoi ous suppoit is usually 25 to 125 μm

Methods of analysis

Among the best-known chiomatogiaphic techniques aie gas chiomatogiaphy, high peifoimance liquid chiomatogiaphy (HPLC) and supei-ciitical fluid chiomatogiaphy (SFC) HPLC methods can be used to sepaiate polai and non-polai compounds, the solv ent (oi mobile phase) and stationaiy phase to be used in an HPLC method aie chosen based upon the types of analytes to be sepaiated With caieful selection of the mobile phase and stationaiy phase, many mixtuies can be sepai ated into

28 w ell-iesoh ed peaks 01 fractions which can be isolated foi fuithei analysis 01 use Chaiacteii7ation by methods such as mass spectiometiy (MS) pioudes information about the analytes picsent m the sample Such a technique, mcoipoiatmg liquid chiomatogiaphy and mass spectioscopy, is called LC/MS

A vanety of HPLC techniques have been iepoited Among the most widely-used aie "noimal phase" HPLC (geneially useful toi lelatively polai analytes, least-polat analytes usually elute fust) and "leveised phase" HPLC (RP-HPLC, geneially used toi less polai analytes, least-polai analytes geneially elute last)

Mass spectiometiy (MS) is a widely used technique foi the identification ot molecules, both m oiganic and moigamc chemistiy MS may be thought ot as a weighing machine foi molecules The weight ot a molecule is a ciucial piece ol inloimation in the identification of unknown molecules, 01 m the identification of a known molecule in a unknown mixtuie of molecules Examples of situations in which MS analysis may be used include diug development and manufactme, pollution contiol analysis, and chemical quality contiol

MS is frequently used in conjunction with othei analysis tools such as gas chiomatogiaphy (GC) and liquid chiomatogiaphy (LC), which help to simplify the analysis of MS spectia by essentially spieadmg out the timing of the aπival of the individual components of a chemical mixtuie to the MS system Thus, the numbei of diffeient moleculai species in the mass spectiometei at any one time is i educed, and sepaiation of mass spectium peaks is simplified This pioceduie woiks well foi chemical samples that contain on the oidei of 10 to 20 diffeient moleculai species, but is inadequate foi analyzing samples that contain thousands of diffeient species

Mass spectiometiy opeiates by fust ionizing the chemical material of inteiest in an ionization souice Theie aie many well known ionization souices in the art, such as electiospiay ionization (ESI) and atmospheiic piessuie chemical ionization (ApCI) The above mentioned ionization methods geneially pioduce what is known in the ait as a piotonated molecule, meaning the addition of a pioton oi a hydiogen nucleus, [M+H]^~\ wheie M signifies the molecule of mteiest, and H signifies the hydiogen ion, which is the same as a pioton

Some ionization methods will also pioduce analogous ions Analogous ions may

29 ause by the addition of an alkaline metal cation, iathei than the pioton discussed abo\ e A typical species might be [M+Na] 01 [M+K]^τ The analysis of the ionized molecules is similai mespectiv e of whethei one is concerned w ith a piotonated ion as discussed above oi dealing \\ ith an added alkaline metal cation The majoi diffeience is that the addition ol a pioton adds one mass unit (typically called one Dalton) foi the case ot the hydiogen ion (i e , pioton), 21 Daltons in the case of sodium, 01 19 Daltons in the case of potassium These additional w eights oi masses aie simply added to the molcculai w eight of the molecule ol mteicst and the MS peak occuis at the point ioi the moleculai weight ot the molecule of inteiest plus the w eight of the ion that has been added

These ionization methods can also pioduce negative ions The most common moleculai signal is the depiotonated molecule [M-H] , in this case the mass is one Dalton lowei than the moleculai weight of the molecule of inteiest In addition, some ionization methods will pioduce multiply chaiged ions These aie of the geneial identification type of [M+nH]n⁺, wheie small n identifies the numbei of additional piotons that have been added

The ions pioduced m any of the ionization methods discussed above aie passed thiough a mass sepaiatoi, typically a magnetic field, a quadiupole electiomagnet, oi a time-of-flight mass sepaiatoi, so that the mass of the ions may be distinguished, as well as the numbei of ions at each mass level These mass sepai ated ions go into a detectoi and the numbei of ions is iecoided

It is often possible to identify the specific moleculai species geneiatmg, a MS signal by discerning its moleculai weight, since diffei ent chemicals typically have ditfeient moleculai weights MS is a poweiful tool in the analysis of unknown puie oi game compounds because it can identify the moleculai weight oi mass of the compound, thus helping to identify the specific compound by limiting the numbei of possible compounds To help analyze complex mixtuies it is known in the pπoi ait to do some piehmmaiy sepaiation of the mixtuie pπoi to mtioduction into the mass spectiometei by the use of gas clnomatogiaphy (GC) oi liquid chiomatogiaphy (LC) Foi example LC/MS (meaning liquid chtomatogiaphy/mass spectiometiy), is fiequently employed in the analysis of diug metabolites m diug disco\ eiy laboiatoiies, wheie it is used to identify which compound has a specific action in living ci eatuies In the above

30 noted examples the LC methods aie used to allow the sample of the unknow n mix tin e of chemicals to entei the mass spectiomctei in a known sequence By know ing how long it takes the mateual of mteiest to mo\ e thiough a liquid chiomatogiaph it is then possible to know at w hat time the mateual w ill entei the mass spectiometei

EXAMPLES

The im ention is fuithei illustiated by the follow ing examples w hich should in no w ay be constiued as being fuithei limiting Lowei molcculai w eight w atei fiee PEI (#40 871-9) and PEI 80% Ethoxylated ^7 w t % solution in watei (#30 618 5) w eie obtained horn Aldiich Eithei PEI w hen added to standai d miciofiltiation nitiocellulose membi ane foimulations, pioduced membianes with mcieased piotein sui lace binding capacity, mcieased suiface addition, mcieased pioduct tensile stinegth, mci eased elongation, mcieased flexibility, and ieduced bnttleness

Example 1

The foimulation includes nitiocellulose in concentiations ianging fiom 8-1 1%, acetone ianging horn 50-80%, butanol iangmg fiom 50-70%, isopiopyl alcohol in concentiation ianging fiom 5-10%, Sodium Dodecyl Sulfate (SDS) in the iange of 5-8%, and polyethylenimme (PEI) in 0 01-2 0% concentiation

Following the blending of the said foimulation, and following an appiopnate ieaction pciiod, this fomiulation is ieady foi casting With a glass slide as the taiget foi inteifacial association, the formulation is applied to the glass slide, excess formulation is lemoved w ith attention given to the final thickness of the coating The slide is allowed to an diy befoie miioduction into a 9O⁰C oven overnight The slides aie allowed to cool and eqiπlibi ate Known volumes of piotems to be examined aie applied to the coated slide, unbound piotein is lemoved, and bound piotems aie quantified and compaied to volumes applied Coated slides with bound piotems can be submitted a vanety of methods of detection including chemilummescence oi chemolummescence

Example 2

31 The foimulation includes mtiocellulose in concentiations ianging horn 8-1 1%, acetone iangmg horn 50-80%, butanol ianging hom 50-70%, isopiopyl alcohol in concentiation ianging fiom 5-10%, Sodium Dodecyl Sulfate (SDS) m the iange of 5-8%, and polyethylemmme ethoxylated in concentiation of 0 01-3 0%

With a com entional flat-stock membiane as the taiget pioduct the foimulation is blended with vaiymg solute concentiation to the desned final poie size Follow ing appiopπate ieaction time, casting of the membiane w ould follow The iesultmg membiane maybe employed in Southern blotting techniques following aiagose gel electiophoiesis of genomic DNA

Example 1

Formulation 24 lngiedient %

Butanol 20-40

Acetone 25-45

IPA 0 5-2 5

SDS(aq) 2 5-4 5

Beigeiac E27 Giade NC 5-20 PEI 0 1-1 5

Acetonitiile 5—20

"SDS solution is made using 5 - 15% SDS in 75 - 95%

The slimy was allowed a ieaction time of 481ns

Properties of Formulation 24

Comparative Standard NC Formulation lngiedient %

Butanol 25 - 45

32 Acetone 33 - 53

IPA 0 5 - 2 5

SDS sol i ¹^

Bcigei ac E27 Giade NC 5 - 25

'SDS solution is made using 5 15% SDS in 75 - 95%

Properties of Comparath e Example

Incoipoiation by Refeiencc

The contents of all ieleiences (including liteiatuic lefetenccs, issued patents published patent applications, and co-pending patent applications) cited lhioughout this application aie heieby expiessly incoipoiated heiem in then entneties by iefeience

Equivalents

Those skilled in the ait will lecogmze, oi be able to ascertain using no moie than ioutme expeπmentation, many equivalents of the specific embodiments of the invention desciibed heiem Such equi\ alents aie intended to be encompassed by the follow ing claims

All of the featuies, specific embodiments and paiticulai substituents disclosed heiem may be combined in any combination Each featuie, embodiment oi substituent disclosed in this specification may be teplaced by an alternative featuie, embodiment oi substituent seiving the same, equivalent, oi similai purpose Thus, unless expiessly stated otherwise, each featuie, embodiment oi substituent disclosed is only an example of a geneiic seπes of equivalent oi similai featuies featuie, embodiments oi substituents

Fiom the above description, one skilled in the ait can easily ascertain the essential chaiacteiistics of the piesent invention, and without departing fiom the spnit and scope theieof, can make vanous changes and modifications of the invention to adapt it to vaπous usages and conditions Thus, othei embodiments aie also within the claims

33

Claims

CLAIMS:

1 A mcmbi ane compiising an ionic blanch polymei and at least one othei polymei

2 The membiane ot claim 1 wheicin the bi anch polymei and the othei polymei foim a polymei blend

3 The membiane of claim 1 oi claim 2, w hei ein the membi ane is a poious membi anc

4 The membiane of claim 3, wheiein the poious membi ane compiises poies ianging in size fiom about 0 01 to about 14 μm

5 The membiane of claim 3 oi 4, wheiein the poies compiise about 5-85% of the membiane suiface

6 The membiane of claim 3, 4 oi 5 wheiein the membiane has a poie density iangmg fiom about 10,000 to about 60,000,000 pei cm²

7 The membiane of anyone of the pieceding claims, wheiein the ionic bianch polymei is selected fiom dendnmeis, aiboiols, polycations, polyanions and polyamphiphiles

8 The membiane of claim 7, wheiein the dendπmei is polyethylenimme (PEI), dextiansulfate, polyomithme, polyaigmme, poly(L-seiine estei ), poly(L-lysme), poly(D- seπne estei), poly(D-lysinc). poly(diallyldimethylammonium chloπde) (PDDA). poly(allylamme) hydiochloiide oi polyvinylimidazole

9 The membiane of anyone of the piecedmg claims, wheiein the othei polymei is selected fiom mtiocellulose (NC ), polysulfone (PU), polyethei sulfone (PES), polyamide

34 (PAM). polywnyhdene difluoiide (PVDF), \ inyhdene fluoπde (VDF), polyethylene (PE). polypiopylene (PP), polystyiene (PS), polyolefins, polyethylene, cellulose acetate (CA), polycaibonates (PC), polyestci substiates, polyethylene teiephthalate (PET), polybutylenc teiephthalate (PBT), poly\ inyl iluonde (PVF), polytetiafluoioethylene (PTFE), fluoiinated ethylene piopylenc (FEP), polyetheiethei ketone (PEEK) polyetheπmide (PEI), polymethylpentene (PMP), polyphylene oxide (PPO), polyphenylenc Sulfide (PPS), polyv inyl chloiide (PVC), polystytene-aciylonitπle (SAN). HFP, polyimide, PTFE, polyaciyloniti ile, polyetheumidc, polyamide-imide, aiomatic polyamide, and copolymeis theieol

10 The membiane of claim 9, w heiem the othei polymei is selected fiom nitiocellulose (NC), polysulfone (PU), polyetheisulfone (PES), polyamide (PAM), polyvmylidene difluoiide (PVDF), polyethylene (PE), polypiopylene (PP), polystyiene (PS), and cellulose acetate (CA)

1 1 The membiane of claim 10, whciein the othei polymei is nitiocellulose

12 The membiane of anyone of the piecedmg claims, wheiem the ionic blanch polymei compiises about 0 001% to about 5 0% of the membiane

13 The membiane of claim 12, wheiein the bianch polymei compiises about 0 01% to about 2 0% of the membiane

14 The membiane of claim 13, wheiem the bianch polymei compiises about 0 01% to about 1 0% of the membiane

15 The membiane of anyone of the piecedmg claims, wheiem the othei polymei compiises about 5% to about 20%> of the membiane

16 The membiane of claim 15, wheiem the othei polymei compiises about 8% to about 1 1% of the membiane

35

17. The membrane of anyone of the preceding claims, further comprising one or more organic solvents.

18. The membrane of claim 17, wherein the organic solvents are selected from acetone, ethyl acetate, methyl acetate, hexane, methanol, ethanol, isopropanol, butanol, toluene, formamide, polyethylene glycol (PEG), polypropylene glycol( PPEG) triethylene Glycol (TEG) polyethylene oxide (PEO). polyacrylates (PAA), dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N.N-dimethyl acetamide (DMAC), methyl ethyl ketone, dichloromethane, and l-methyl-2-pyrrolidinone (NMP), triethyl phosphate (TEP) poly(acrylamide (PAM), dibasic esters (DBE ), dichloromethane, hexane.

19. The membrane of claim 17 or 18, wherein the one or more organic solvents comprise about 30% to about 90% of the membrane.

20. The membrane of claim 19, wherein the one or more organic solvents comprise about 50% to about 80% of the membrane.

21. The membrane of anyone of the preceding claims, further comprising one or more surfactants.

22. The membrane of claim 21 , wherein the surfactants are selected from sodium dodecyl sulfate (SDS), Neodol, Tergitol, Pluronic, alkyl ether sulphates, acyl lactylates, acyl methyl taurates, acyl isethionates, alkyl sulphates, acyl sarcosinates, alkyl sulphosuccinates, alkyl ether sulphosuccinates and polyethoxilates.

23. The membrane of claim 22, wherein the surfactant is sodium dodecyl sulfate (SDS).

24. The membrane of claim 21 , 22 or 23, wherein the surfactant comprises about 2% to about 10% of the membrane.

36 2"i The membianc of claim 24, u heiein the suifactant compπses about 5% to about 8% of the membiane

26 The membiane of anyone of the picceding claims, wheiein the poious membiane has a thickness ianging between about 1 μm to about 500 μm

27 The membiane of claim 26, wheiein the membiane thickness ianges iiom about 100 μm to about 300 μm

28 The membiane of anyone of the pieceding claims which is utilized as a cast oi a coating

29 The membiane of claim 28, wheiein the membiane is a coating of solid substiates, poious substiates, oi semi-poious substiates

30 The membiane of claim 29, wheiein the substiate consists of a shape selected fiom a plate, a panel and a tube

31 The membiane of claim 30, wheiein the plate oi panel is a micio plate oi micio panel

32 The membiane of claim 31 , wheiein the micio plate oi micio panel consists of none-woven matenals, glass, polycaibonate, polyestei, PVDF, PES, PS, PP, PE, oi CAB

33 The membiane of claim 30, wheiein the tube consists of none-woven matenals, glass, polycaibonate, polyestei, PVDF, PES, PS, PP, PE, oi CAB

34 The membiane of claim 33, wheiein the tube has an inside diametei iangmg horn 1 mm to about 500 mm, and an outside diametei iangmg fiom about 2 0 mm to about 900 mm

37 I^s! The membiane ot claim 34, wheiein the tube has an mside diamctei i angmg ttom 2 mm to about 250 mm, and an outside diametei ianging Ii om about 3 5 mm to about 500 mm

36 A membiane compπsmg polyethylenimine, nitiocellulose, an oiganic soKent, and a suifactant

37 The membiane of claim 36, wheicm the polyethylenimine compπses about 0 01% to about 2 0% of the membtanc

38 The membiane ol claim 36 oi 37, wheiein the nitiocellulose compiises about 8% to about 1 1% ol the membiane

39 The membiane ol claim 36, 37 oi 38 wheiein the oiganic solvent compiises about 50% to about 80% of the membiane

40 The membiane of claim 36, 37, 38 oi 39, wheiein the suifactant compiises about 5 0%) to about 8 0% of the membiane

41 A membiane compnsmg dextian sulfate, nitiocellulose, an oiganic solvent, and a suifactant

42 The membiane of claim 41 , wheiem the dextian sulfate compiises about 0 05% to about 5 0% of the membiane

43 A device foi binding at least one taiget molecule, compnsmg a poious membiane in accoi dance with anyone of claims 3 to 35

44 The device of claim 43, wheiem the membiane binds taiget compounds consisting of small molecules, maciomolecules, pai tides and cellulai systems

38

45. The dev ice of claim 44, wherein the target compounds bind to the porous membrane at a pore surface.

46. The device of claim 44 or 45, wherein the target compounds are selected from the group consisting of nucleic acids, proteins and ligands.

47. The device of claim 46, wherein said target compounds are proteins.

48. The device of claim 46, wherein said target compounds are oligopeptides or polypeptides.

49. The device of claim 46, wherein the target compounds are nucleic acids.

50. The device of claim 46, wherein the target compounds are DNA, oligonucleotides or polynucleotides.

51. The device of anyone of claims 44 to 50, wherein the target compounds bind to the membrane at about 20% to about 75% of the total target compounds applied to the membrane.

52. The device of claim 51 , wherein the target compounds bind to the membrane at about 40% to about 60% of the total target compounds applied to the membrane.

53. The device of anyone of claims 43 to 52 wherein the porous membrane is effective for carrying out an analytical task selected from the group consisting of sequence analysis by hybridization, analysis of patterns of gene expression, immunochemical analysis of protein mixtures, epitope mapping, assay of receptor-ligand interactions and profiling of cellular populations involving binding of molecules to ligands or receptors.

39 54 The de\ ice of claim anyone of claims 43 to 53, fiuthei compiismg a detectoi foi detection of binding of the poious tiack etched membiane with the taiget compound

55 A method foi binding a taiget molecule, compiismg contacting the taiget molecule with a device in accoidance with anyone of claims 43 to 54, and detecting whethei binding has occuiied between the membiane and the taiget compound. wheiein the membiane compπses a plutality of poies. and wheiein the poies bind to a taiget molecule

40