WO2007017260A2

WO2007017260A2 - Sensor with multi-phase, segmented polymer network

Info

Publication number: WO2007017260A2
Application number: PCT/EP2006/007863
Authority: WO
Inventors: Michael Hanko; Jürgen HEINZE; Jörg TILLER; Nico Bruns; Sara Rentmeister
Original assignee: Albert-Ludwigs-Universität Freiburg
Priority date: 2005-08-11
Filing date: 2006-08-09
Publication date: 2007-02-15
Also published as: DE102005037979B4; DE102005037979A1; WO2007017260A3

Abstract

The present invention relates to a sensor, in particular for the qualitative and/or quantitative determination of analytes in gaseous and/or liquid samples, comprising at least one polymer material and at least one indicator substance, as well as to a method for producing such a sensor and the use thereof. The polymer material is characterised in that it is an at least two-phase, segmented polymer network in which the at least one indicator substance is immobilised.

Description

Sensor with multiphase, segmented polymer network

description

The present invention relates to a sensor, in particular for the qualitative and / or quantitative determination of analytes in gaseous and / or liquid samples, comprising at least one polymeric material and at least one indicator substance, and a method for producing such a sensor and its use.

Sensors of the type mentioned above have a sensitive layer of a polymeric material which changes one of its physical properties on contact with an analyte, for example a noxious gas or a pollutant solution. Especially in the case of optically evaluable sensors, the change in absorption of the sensitive layer is frequently evaluated as a measured variable. Aside from a polymeric material, the sensitive layer usually has at least one indicator substance which is immobilized in the polymeric material. In this case, the strongest possible immobilization of the indicator substance is desired since it can otherwise elute from the polymeric material, in particular during use, but also during storage of the sensor.

The polymeric material used to immobilize an indicator substance must meet at least two requirements. On the one hand, the indicator substance used must firmly adhere to the polymeric matrix, so that it can not migrate or the indicator substance is flushed out on contact with an analyte, on the other hand, the polymeric matrix must be sufficiently permeable to the analyte, such as a noxious gas or a pollutant solution, so the analyte can come into contact and (optionally) react with the indicator substance.

In order to solve this problem, the prior art discloses a large number of predominantly polymeric matrix materials which immobilize the indicator substance via various interactions. In some cases, chemically-modified indicator substances are also used, or adjuvants are added to the polymeric material, for example phase-mediated reagents. Thus, for example, DE 199 57 708 A1 discloses a process for the immobilization of color indicators in polymer membranes, in which a color indicator such as o-tolidine or bromophenol blue is immobilized in a silicone-polycarbonate copolymer membrane. The immobilization takes place primarily via hydrogen bonds. However, a disadvantage of the sensors known from the prior art is that a particular polymeric material must be used in each case for numerous indicator substances to be used, or the indicator substance must be chemically modified accordingly in order to be sufficiently immobilized in a given polymeric material. For this purpose, expensive tests are often necessary in individual cases. Likewise, the use of particular phase-mediated reagents is not always possible. In addition, a variety of the known polymeric materials are not sufficiently permeable, so that in particular a sensitive and rapid measurement, for example, at a given gas flow is not possible. Furthermore, it is often necessary to add the indicator substances already during production of the polymer matrix of the sensor, so that in particular a subsequent and controlled introduction of the indicator substance into a polymeric matrix is not possible. As a result, problems are caused in particular in the presence of a solvent incompatibility of the indicator substance with the polymeric matrix material, so that at best only an inhomogeneous distribution of the indicator substance takes place here. As a result, repeatable results and determinations, in particular of a quantitative nature, of, for example, noxious gases are prevented; moreover, an elution of the indicator substance from the polymer matrix often occurs. In addition, often the polymeric sensor matrix materials are soluble in solvents, whereby a use of such sensors for qualitative and / or quantitative determination in liquids is excluded. Finally, if only weak interactions such as van der Waals interactions work between the polymeric material used and the indicator substance, then the concentration of the indicator substance in the polymeric matrix is also limited since otherwise phase separation processes take place and the indicator substance crystallizes out. As a result, the sensitivity of corresponding sensors is limited, and in particular the measurement periods are lengthened, while at the same time the possible exposure duration of sensors that work integratively over longer periods according to the dosimeter principle is shortened.

It is therefore an object of the present invention to provide a sensor which does not have the disadvantages known from the prior art.

This object is achieved according to the invention by a sensor, in particular for the qualitative and / or quantitative determination of analytes in gaseous and / or liquid samples, in particular comprising at least one polymeric material and at least one indicator substance, wherein the polymeric material comprises at least two-phase, segmented, in particular nanophase-separated polymer film formed as a polymer in which the at least one indicator substance is immobilized. For the purposes of the present invention, and also in general, segmented polymer networks are network structures in which a polymer A is crosslinked with at least one further polymer B. For the purposes of the present invention, at least two-phase means that the polymer network has a spatially separated phase structure, wherein the separation of the phases can also take place only due to entropic effects. Preferred within the meaning of the present invention are polymer networks with separated phases of different hydrophilicity and / or hydrophobicity, as well as polymer networks with exactly two phases. Examples of two-phase systems are, for example, amphiphilic polymer networks. Preference is given to polymer networks which have hydrophilic and hydrophobic units. Nanophase-separated according to the present invention means that the polymer network, which is formed from the polymeric sensor material has a segmentation in at least two phases, which are preferably formed as cocontinuous phases, wherein the phase units thus formed are in the nanometer range, ie thickness or Diameter maximum about 1000 nm.

The segmentation or nanophase separation can be monitored and determined, for example, by AFM measurements (atomic force microscopy measurements). For simplicity, in the sense of the present invention, the three-dimensional information about the nanophase separation obtained by AFM measurements is translated into a one-dimensional or two-dimensional variable. The nanophase-separated polymer networks of the present invention preferably have hydrophilic or hydrophobic walls or domains. Preferably, the nanophase separation of the polymer network according to the present invention is given both on the surface and in the mass of the polymeric sensor material. On the one hand, sufficient permeability of the polymeric sensor matrix is ensured on the one hand, and on the other hand, one or more indicator substances and other materials, such as, for example, enzymes, can be immobilized in the polymeric material in a controlled and separate manner. As a result, the sensors according to the invention are suitable both for use in the liquid phase, be it in the aqueous phase or in organic solvents, but also for the use of gas determinations. When measuring pollutant solutions, the solvent used, such as water or an organic solvent, preferably has a different polarity than the phase formed by the polymeric material and the at least one indicator substance.

At least two-phase within the meaning of the present invention includes not only Polymer networks, which have hydrophilic and hydrophobic units, but also those polymer networks, which have amphiphilic and non-amphipilic areas. Such polymers are usually formed as block copolymers, triblock copolymers, etc. of the construction type AB, ABA, BAB, etc., which are used as building blocks for the production of the segmented, multi-phase polymer network. Such block copolymers, triblock copolymers, etc. can be formed by means of certain monomers into polymer networks with amphiphilic and non-amphiphilic units. An example here is the polyethylene glycol ό-polypropylene glycol-6-polyethylene glycol available from the company BASF, Ludwigshafen, Germany, available under the trade name Pluronic.

The at least two-phase, segmented polymer network of the sensor according to the invention is designed such that the size of the segmented units is not smaller than the indicator substances to be stored in this or other substances such as enzymes. Depending on the nature of the solvent in which the indicator substance is dissolved, either the more hydrophobic or the more hydrophilic areas of the nanophase-separated polymer network swell, so that the indicator substance and / or the further used enzyme diffuse into the polymer network and either to the can attach more hydrophilic or more hydrophobic units. As a result, a uniform distribution of the indicator substance in the nanophase-separated polymer network is obtained while the binding of the indicator substance after drying in this same, so that the sensor according to the invention can be provided in a uniform and reworkable quality.

Advantageously, the polymeric material has hydrophobic domains with a diameter in a range from about 5 to about 500 nm, preferably from about 8 to about 300 nm, more preferably from about 8 to about 50 nm, the latter ranges especially for immobilizing additional enzymes , More preferably, the polymeric material has hydrophilic walls having a thickness in a range from about 5 to about 500 nm, preferably from about 8 to about 300 nm, more preferably from about 8 to about 50 nm, the latter ranges especially for immobilizing additional enzymes. Due to this morphology, the polymeric sensor material is designed to accommodate and immobilize a variety of different indicator substances and / or enzymes. At the same time, a sufficient permeability for the gaseous or liquid substances or mixtures to be determined is made possible.

In at least two-phase, segmented, in particular nanophase-separated polymer networks according to the present invention, the polymer chains thereof are the same three-dimensionally interconnected. Preferably, therefore, a single large molecule is present as a polymeric network. The synthesis of the polymeric networks used in the sensor according to the invention can be carried out in principle by crosslinking of linear polymer chains by means of a polymer-analogous reaction or by crosslinking copolymerization with a crosslinker. In the copolymerization macromonomers can be used instead of monomers. For the purposes of the present invention, this term is understood to mean oligomers or polymers having polymerizable groups. Copolymerization of a macromonomer modified in both end groups with a polymerizable group and a low molecular weight monomer results in networks with a segmented topology located between the grafted or comb polymers and those of interpenetrating networks. Such segmented polymer networks have nanophase separation and are commonly referred to as poly (A) -linked poly (B), where poly (B) is a polymeric crosslinker for monomer (A). If, in a network composed of at least two components, according to one of the preferred embodiments of the present invention, one polymer component is hydrophilic and the other hydrophobic, the nanophase-separated polymer network obtained by polymerization is in a wide range of compositions of the two starting components both in organic solvents also swellable in aqueous media. In this case one speaks of an amphiphilic network. Although a phase separation actually occurs between the polar and nonpolar components or chain segments of the nanophase-polymer network, macroscopic phase separation is prevented by the covalent bonds between the individual segments. This results in domains or walls in the polymer network with predominantly hydrophilic or hydrophobic properties. Amphiphilic polymer networks in the context of the present invention are composed of immiscible, ie incompatible polymer chains. The polymer network of the sensor according to the invention is preferably produced by copolymerization of a monomer (hydrophilic or hydrophobic) with a macromonomer (hydrophobic or hydrophilic) or by copolymerization of two macromonomers of different hydrophilicity.

Preferably, the component for producing the hydrophobic unit of the polymeric material is selected from a group comprising alkyl (meth) acrylates, styrene, vinyl acetates, olefins, poly (ε-caprolactone), lactic acid, diisocyanates, diols, diamines, diacids, polyactides, Polypropylene fumarate, diglycidyl ethers of, for example, bisphenol A, polytetrahydrofuran and / or polyalkyloxazolines (for example 2-phenyloxazoline), perfluoropolyethers or siloxanes, for example dimethylsiloxane, and copolymers of the abovementioned Substances. Particularly preferred is the use of a polydialkylsiloxane macromonomer as the hydrophobic component of the polymer network of the sensor according to the invention, wherein a polydimethylsiloxane macromonomer is particularly preferably used. Preferably, therefore, the hydrophobic moiety generating component comprises a polydimethylsiloxane macromonomer having a molecular weight M _n in a range of about 500 to about 1 million g / mol, more preferably in a range of about 1,000 to about 500,000 g / mol , For the synthesis of the polymeric material for the sensor according to the invention, an α, ω-end-functionalized polydialkylsiloxane macromonomer, for example a bifunctional α, ω-methacryloyloxypropyl-functionalized polydimethylsiloxane (PDMS) macromonomer, is preferably used for the synthesis of the polymeric material

(MA-PDMS-MA) used. The substance used to form the hydrophilic unit of the polymer network is not specifically limited. The component for producing a hydrophilic unit is particularly preferably selected from a group comprising (meth) acrylate and its derivatives, diisocyanates, diols, diamines, diacids, acrylamide, N-isopropylacrylamide, N-vinylcaprolactam, 2,3-

Dihydroxypropyl methacrylate, maleic acid, fumaric acid or vinyl acetate as monomers and / or as macromonomers, poly-1, 3-dioxolane, polyethyleneimine, polypropyleneimine, polyethylene glycol, polypropylene glycol and polyoxazolines with (meth) acrylate, epoxy, amino, isocyanato or hydroxyl end groups , Particularly preferred hydrophilic components are (meth) acrylic acid and (meth) acrylates and derivatives thereof, in particular hydroxyethyl (meth) acrylate, dimethylacrylamide and dimethylaminoethyl (meth) acrylate. With the names (meth) acrylic acid or (meth) acrylate are named for the purposes of the present invention, acrylic acid and methacrylic acid or acrylate and methacrylate.

Preferably, the polymeric network is insoluble in solvents, and advantageously swellable in solvents. The polymeric material is preferably disposed on a carrier. This support means is selected such that it does not hinder the determination of in particular harmful gases and pollutants by means of the sensor according to the invention. Thus, in particular in the case of a sensor according to the invention, which is optically evaluable, a glass carrier may be provided as the carrier means, preferably a glass carrier made of a borosilicate glass. Preferably, the polymeric material is covalently bonded to the carrier. This is achieved by a special pretreatment of the carrier, in particular a glass carrier.

Advantageously, the polymeric material of the sensor according to the invention is formed as a film. This film is advantageously translucent, more advantageously wise transparent and clear. The film preferably has a thickness in a range from about 0.1 μm to about 1000 μm, preferably from about 1 μm to about 200 μm. The film can be arranged on one or both sides of a carrier, in particular also in several layers one above the other. Also, a reflective layer can be applied between the support and the film or on the back of the transparent support for measurement in reflection.

The indicator substance in the sensor according to the invention is advantageously immobilized by van der Waals interactions, dipole-dipole interactions, hydrogen bonds, ionic interactions as well as covalent bonds to the polymeric network material therein.

The sensor according to the invention advantageously also comprises at least one enzyme which, like the indicator substance, is advantageously immobilized in the at least two-phase, segmented, in particular nanophase-separated polymer network of the polymeric material. This makes it possible to carry out enzyme-catalyzed reactions in the polymer network, in which case the product of enzymatic catalysis can be determined, for example, optically or electrochemically. In this way it is possible, for example, to reliably determine harmful gases or pollutants (in the liquid phase) which can not be measured by optical evaluation units, thereby making it possible to inexpensively avoid the acquisition of additional evaluation units.

Enzymes which can be used in the sensor according to the invention are, for example, horseradish peroxidase (HRP) or chloroperoxidase (CPO), which are incubated in an aqueous enzyme solution. After drying the sensor, the enzyme is in the hydrophilic unit of the nanophase-separated polymer network, which has a high activity. In this way, for example, peroxides in organic solvents can be determined by enzymatically HRP-catalyzed reactions with an optical evaluation unit in the visible range when a suitable indicator substance is selected. For example, loads of the nanophase-separated polymer network of the sensor according to the invention in a range of about 1 to about 100 micrograms of enzyme per cm ^{2 of} the 20 micron thick film of a polymer network are possible.

Furthermore, the present invention relates to a method for producing a sensor according to the invention, wherein an at least two-phase, segmented, in particular nanophase-separated polymer network is produced by copolymerization two macromonomers of different hydrophilicity or of a monomer and a macromonomer, each having different hydrophilicity and this are loaded with at least one indicator substance. Particularly preferred is the alternative that a monomer and a macromonomer, each having different hydrophilicity is co polymehsiert, more preferably, a hydrophobic macromonomer is copolymerized with a hydrophilic monomer. In order to prevent that the strong incompatibility between the different chain segments does not lead to a macroscopic phase separation already in the synthesis, advantageously the at least two-phase, segmented, in particular nanophase-separated polymer network is polymerized in bulk, advantageously using protective group-modified monomers, to obtain a sufficient mixing of the components used. An example of this is the replacement of the hydrophilic monomer (meth) acrylic acid ((M) AA) by the hydrophobic trimethylsilyl (meth) acrylate (TMS (M) A), which is well compatible with hydrophobic macromonomers. In the course of the copolymerization, a precursor network is first formed, the polar chain segments of which carry trimethylsilyl protective groups. By hydrolysis with alcohol / water mixtures, these protective groups can then be split off, so that an amphiphilic network with hydrophilic and hydrophobic units is then obtained.

More preferably, the polymer network is loaded with at least one enzyme in addition to the at least one indicator substance. The loading preferably takes place during the addition of the at least one indicator substance, but it can also take place before the addition of the at least one indicator substance, but also subsequently.

Advantageously, the at least two-phase, nanophase-separated polymer network is carried out by UV-initiated radical copolymerization. Alternatively, any other method of copolymerization may be provided. Preferably, a UV-initiated free-radical copolymerization of PDMS macromonomers and (meth) acrylates or their derivatives is carried out, wherein (meth) acrylic acid ((M) AA), hydroxyethyl (meth) acrylate (HE (M ) A) and dimethylaminoethyl (meth) acrylate (DMAE (M) A) can be used. (M) AA and HE (M) A can be incorporated into the polymer network in the form of their hydrophobic trimethylsilyl-protected derivatives, after which the protective groups are subsequently removed to obtain an at least two-phase, nanophase-separated network. The present invention further relates to the use of a polymeric material, which is designed as an at least two-phase, segmented, in particular nanophase-separated polymer network and is loaded with at least one indicator substance, as sensor material. Finally, the present invention relates to the use of the sensor according to the invention for the quantitative and / or qualitative determination of analytes in a liquid and / or gaseous sample, in particular of noxious gases and / or pollutant solutions. The determination is preferably carried out by optical methods, in particular by UV-VIS spectroscopy, but for example by NIR or FTIR spectroscopy. But also, for example, an evaluation by means of electrochemical methods, for example by measurements of overvoltages and in particular by means of the so-called SECM method (Scanning Electro Chemical Microscopy) is possible depending on the indicator substances used and analytes to be determined. In this case, the sensor according to the invention can be designed such that it is hereby measured in situ, for example, at a certain gas flow, but it can also be designed, for example, as a passive sensor for particularly large measuring periods. An optical evaluation of the sensor according to the invention can be carried out both in the transmission and in the reflection mode, including a measurement by multiple reflection.

These and other advantages of the present invention will become more apparent from the following examples and drawings. Show it:

Fig. 1: Chemical structure of 3-methacryloyloxypropyltrimethoxysilane;

Fig. 2: Chemical structure of trimethylsilyloxyethyl acrylate (TMSOEA);

Fig. 3: Chemical structure of methacrylate-terminated polydimethylsiloxane

(MA-PDMS-MA) with n * 66);

Fig. 4: Chemical structure of the prepared nanophase-separated amphiphilic

Polymer network based on polyacrylate-polydimethylsiloxane copolymers (uncharged: R = O-CH ₂ -CH ₂ -OH; cationic: R = -CH ₂ -CH ₂ -N (Me) ₃ ⁺ ; anionic: R = 0 ^" ) with n, m, r, s> 1 and q = 66;

Fig. 5: Chemical structure of N, N'-diphenyl-1,4-phenylenediamine (DPPD); FIG. 6 shows changes in the transmission spectrum of a sensor according to Example 1 when gassing with 5 ppm of NO ₂ in synthetic air over 10 minutes; FIG.

Fig. 7: Transmission change at 450 nm of a sensor chip according to Example 1 with gassing with 5 ppm NO ₂ in synthetic air over 10 min;

Fig. 8: Chemical structure of dimethylaminoethyl acrylate (DMAEA);

9 shows a change in the transmission spectrum of a sensor chip according to Example 2 when gassing with different proportions by volume of AcOH in synthetic air at 60% relative humidity over 60 minutes;

FIG. 10: Transmittance change at 425 nm of a sensor according to Example 2 at

Gassing with different proportions of AcOH in synthetic air at 60% relative humidity over 60 minutes;

Fig. 11: Chemical structure of trimethylsilyl acrylate (TMSA);

Fig. 12: Changes in the transmission spectrum of a sensor according to Example 3 when gassed with 10 ppm H ₂ S in synthetic air at 60% relative

Humidity over 10 min;

Fig. 13: Transmittance change at selected wavelengths of a sensor according to Example 3 when gassed with 10 ppm H ₂ S in synthetic air at 60% relative humidity over 10 min;

Fig. 14: Chemical structure of diphenylamine;

Fig. 15: Changes in the transmission spectrum of a sensor according to Example 4 when gassed with 100 ppb NO ₂ in air at less than 5% relative humidity over 21 days;

Fig. 16: Transmittance change at 390 nm of a sensor according to Example 4 at

Fumigation with 100 ppb NO ₂ in air at less than 5% relative humidity over 21 days; FIG. 17: Chemical structure of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diamonium salt (ABTS); FIG.

FIG. 18: Change in absorption at 414 nm after addition of tert-butyl hydroperoxide to a biosensor according to Example 5.

Example 1: Sensor for the detection of nitrogen dioxide in gaseous samples

Surface functionalization of glass slides:

(Cavalier, Säzava, Czech Republic SIMAX ^®) of the size 15 x 7 x 1 mm ³ of concentrated at room temperature in a solution of 70 vol .-% for cleaning glass substrate made of borosilicate glass were. Sulfuric acid and 30 vol .-% hydrogen peroxide solution (30% in water) for one hour in an ultrasonic bath. The glass slides were washed three times with distilled water and dried in an oven at 50 ^° C. overnight. In order to functionalize the surface of the glass supports with methacrylate groups, the glass supports were heated at room temperature for two hours in a 20% by volume solution of 3-methacryloyloxypropyltrimethoxysilane (Figure 1) (Fluka, Steinheim, Germany) in toluol (pa, Fa. Merck, Darmstadt, Germany) and then treated for 10 min in an ultrasonic bath. The glass slides were placed in a vessel with dest. Transferred water and treated for 5 min in an ultrasonic bath. This process was repeated and then the glass slides with about 10 ml dest. Rinsed off water. The oberflächenfunktio- ized glass slides were stored in vacuo (0.1 mbar) at 40 ° C overnight and until further use in a refrigerator at -40 ⁰ C.

Synthesis of polymer networks:

For the production of films from polymer networks, 11.75 mg of the photoinitiator Lucirin TPO (BASF, Ludwigshafen, Germany) in 576 μl of freshly distilled trimethylsilyloxyethyl acrylate (TMSOEA, FIG. 2) were dissolved in a rolled-edge glass with stirring. Subsequently, 1153 μl of methacrylate-terminated polydimethylsiloxane (MA-PDMS-MA, Figure 3, own illustration) having a molecular weight of 5200 g ^• mol ^{-1 were} added, and the solution was stirred for a further 10 minutes, resulting in a volume ratio of TMSOEA to MA PDMS-MA of 33% to 67% Under argon atmosphere, 12 μl of this solution were then applied to a tesafilm-bonded glass slide (76 × 26 × 1 mm ³ ) and a methacrylate-functionalized glass support was applied bubble-free the glass carrier became from a distance of 30 cm with a 500 W Nitraphot lamp (Osram GmbH, Munich, Germany) exposed four times for 60 s each with 15 s exposure pause. Thereafter, the glass slide with slide was turned over and exposed through the slide twice for 60 s with 15 s rest. Under room air, the transparent films of polytrimethylsilyloxyethyl acrylate / polydimethylsiloxane polymer network (PTMSOEA - / - PDMS) firmly anchored to the functionalized glass slide were removed from the Tesafilm-coated slide using a scalpel.

Chemical modification of the polymer networks:

To remove the trimethylsilyl groups (TMS groups), the PTMSOEA - / - PDMS-coated glass slides were washed three times for one day in a 50% by volume solution of methanol (pa; Riedel-de Haen, Steinheim, Germany) in dist , Shaking with water until no signals of the TMS protective group were recognizable in the ATR-FTI case. Subsequently, the transparent glass carriers coated with the uncharged nanophase-separated amphiphilic polyhydroxyethyl acrylate / polydimethylsiloxane polymer network (PHEA / PDMS) were also included Rinsed about 10 ml of methanol and dried overnight in vacuo (0.1 mbar) at 40 ⁰ C.

Loading the Polymer Networks with Indicator Reagent:

The PHEA - / - PDMS-coated glass slides were incubated for about 15 min in a solution of 2 mg ^• ml ^'1 N, N'-diphenyl-1, 4-phenylenediamine (DPPD, Fig 4; Aldrich, Steinheim, Germany.. ) in toluene (pa) and after brief drying in room air, the back of the coated glass slide with a cotton swab soaked in toluene of DPPD residues cleaned. / - - Subsequently, the transparent PHEA were PDMS coated and DPPD-loaded glass support under vacuum (1 mbar) at 30 ⁰ C. Further storage took place in an airtight container in the dark and at room temperature.

Use as sensor:

The PHEA / PDMS coated and DPPD loaded glass slides (PHEA / PDMS DPPD sensor chips) were excellently suited for the detection of nitrogen dioxide (NO ₂ ) in gaseous samples. For this purpose, using mass flow regulators (type F-201C-RAA-33-E, Bronkhorst Hi-Tec, Ruurlo, Netherlands), a gas mixture of 5 ppm by volume of NO ₂ in synthetic air (20.5% O ₂ in N ₂ ) with a voucher stream of 1000 ml ^• min ^'1 produced. The NO ₂ was taken from a test gas cylinder, the synthetic air from a compressed gas cylinder (both Messer Griesheim GmbH, Krefeld, Germany). The gas mixture produced in this way was passed through a measuring tube made of quartz glass (Hellma, Müllheim, Germany) in which a PHEA / PDMS DPPD sensor chip was attached in such a way that it was perpendicular to the measuring beam of a UV / VIS spectrophotometer (Omega 20, Bruins Instruments, Puchheim, Germany).

The periodic recording of transmission spectra showed a rapid change in the transmission spectrum of the PHEA - / - PDMS-DPPD sensor chips (Figure 5). By plotting the change in transmission at a wavelength of 450 nm versus time, an approximately linear curve was obtained in the initial region, the slope of which depended on the NO ₂ concentration and thus could be used to calibrate the sensor (FIG. 6).

Example 2: Sensor for the detection of sulfur dioxide in gaseous samples

Surface functionalization of glass slides:

As in Example 1.

Synthesis of polymer networks:

To produce films from polymer networks, 13.58 mg of the photoinitiator Lucirin TPO in 667 μl of decalin (from Aldrich, Steinheim, Germany) were dissolved in a rolled-edge glass while stirring. Subsequently, 444 ul of freshly distilled N ₁ N- dimethylaminoethyl acrylate (DMAEA, FIG. 7; Aldrich, Steinheim, Germany.) And 888 ul MA-PDMS-MA (see Example 1) was added and the solution stirred for a further 10 min. This resulted in a volume ratio of DMAEA to MA-PDMS-MA of 33% to 67%. The further procedure was carried out as described in Example 1. Solid films anchored to the functionalized glass slide were obtained from poly-N ₁ N-dimethylaminoethyl acrylate-W polydimethylsiloxane polymer network (PDMAEA - / - PDMS).

Chemical modification of the polymer networks: For purification, the PDMAEA - / - PDMS coated glass slides were rinsed three times with about 5 ml each of dichloromethane (pa, Fisher Scientific, Loughborough, UK). After drying in vacuo (1 mbar) at 40 ⁰ C the PDMAEA-Z-PDMS-coated glass support for partial quaternization of the amino groups of 120 were min in a solution of 10 vol .-% dimethyl sulfate (Messrs. Fluka, Steinheim, Germany) in Acetonitrile (Riedel-de-Haen, Seelze, Germany) shaken at room temperature, then rinsed three times with about 5 ml of water and dried in vacuo (1 mbar) at 40 ⁰ C. Solid films anchored to the functionalized glass slide were obtained from poly-N, N-trimethylaminoethylacrylyl sulfate-co-poly-N, N-dimethylaminoethyl acrylate, W-polydimethylsiloxane polymer network (PTMAEA-S-co-PDMAEA - / - PDMS).

Loading the polymer networks with indicator reagent:

The PTMAEA-S-co-PDMAEA - / - PDMS-coated glass slides were placed in an aqueous solution of 0.107 mM bromophenol blue sodium salt (Na-BPB) (Merck, Darmstadt, Germany) for 60 minutes, then approximately three times each 5 ml of dist. Rinsed water and dried in vacuo (0.1 mbar) at 40 ⁰ C overnight. Fixed, BPB-loaded, transparent films (PTMAEA-SZ-BPB-CO-PDMAEA-Z-PDMS) were anchored to the functionalized glass slide. Further storage took place in an airtight container in the dark and at room temperature.

Use as sensor:

The PTMAEA-SZ-BPB-co-PDMAEA / PDMS coated glass slides (PTMAEA-SZ-BPB-co-PDMAEA - / - PDMS sensor chips) were excellently suited for the reversible detection of acetic acid (AcOH) in gaseous samples , For this purpose, according to Example 1, a gas mixture of different proportions by volume AcOH in Synthetic air with a flow rate of 1000 ml ^• min ^'1 and a relative humidity of 60% was prepared. The concentration of AcOH was adjusted by passing different proportions of synthetic air through about 10 ml of AcOH (> 99.8%) (Riedel-de-Haen, Seelze, Germany), the moistening was carried out by means of a dest. Water filled gas wash bottle. The gas mixture thus prepared was passed through a quartz glass measuring cuvette in which a PTMAEA-SZ-BPB-co-PDMAE - / - PDMS sensor chip was mounted so as to be irradiated vertically by the measuring beam of a UVZVIS spectrophotometer. The periodic recording of transmission spectra revealed a rapid change in the transmission spectrum of the PTMAEA-S / BPB-co-PDMAE / PDMS sensor chips as a decrease in transmission at 425 nm in the presence of AcOH (Figure 8), as well as an increase on the initial value of transmission in the subsequent absence of AcOH. By plotting the change in the transmission at this wavelength versus time, the variation shown in Fig. 9 was obtained by varying the AcOH concentration. The transmission decrease was dependent on the AcOH concentration and can therefore be used to calibrate the sensor.

Example 3: Sensor for the detection of hydrogen sulfide in gaseous samples

Surface functionalization of glass slides:

As in Example 1.

Synthesis of polymer networks:

In order to produce films from polymer networks, 13.58 mg of the photoinitiator Lucirin TPO in 800 μl of freshly distilled TMSOEA (see Example 1) were dissolved in a roll-top glass while stirring. Subsequently, 400 μl of freshly distilled trimethylsilyl acrylate (TMSA, Fig. 10, Aldrich, Steinheim, Germany) and 800 μl of MA-PDMS-MA (see Example 1) were added and the solution was stirred for a further 10 min. This resulted in a volume ratio of TMSA to TMSOEA to MA-PDMS-MA from 20% to 40% to 40%. The further procedure was carried out as described in Example 1. Solid films anchored to the functionalized glass slide were obtained from polytrimethylsilyl acrylate-co-polytrimethylsilyloxyethyl acrylate / polydimethylsiloxane polymer network (PTMSA-co-PTMSOEA - / - PDMS).

Chemical modification of the polymer networks:

To remove the trimethylsilyl groups, the procedure was as described in Example 1. Polyacrylate-co-polyhydroxyethylacrylate / polydimethylsiloxane polymer network (PAA-CO-PHEA - / - PDMS) transparent films anchored firmly to the functionalized glass slide were obtained.

For partial deprotonation of the polyacrylic acid residues, the PAA-co-PHEA - / - PDMS-coated glass slides were immersed in a 0.1 M aqueous potassium carbonate solution for 10 min. Solution with a pH of about 12, then twice with about 5 ml of dist. Rinsed briefly water and dried under vacuum (1 mbar) at 40 ⁰ C. Solid films anchored to the functionalized glass slide were obtained from polyacrylate-acrylate-co-polyhydroxyethyl acrylate / polydimethylsiloxane polymer network (PKA-co-PHEA - / - PDMS).

Loading the Polymer Networks with Indicator Reagent:

The PKA-co-PHEA - / - PDMS-coated glass slides were placed in a solution of 50 mM lead (II) acetate (Merck, Darmstadt, Germany) in methanol (pa) for 60 min, then three times with about 5 rinsed methanol and dried overnight under vacuum (0.1 mbar) at 40 ⁰ C. Solid films anchored to the functionalized glass slide were obtained from poly-lead (II) acrylate-co-polyhydroxyethyl acrylate / polydimethylsiloxane polymer network (PBA-CO-PHEA - / - PDMS). The further storage was carried out in an airtight container in the dark and at room temperature.

Use as sensor:

The PBA co-PHEA / PDMS coated glass slides (PBA-co-PHEA - / - PDMS-

Sensor chips) were excellently suited for detection of hydrogen sulfide (H ₂ S) in gaseous samples. For this purpose, a gas mixture of 10 ppm H ₂ S in synthetic air with a volume flow of 1000 ml ^• min ^-1 and a relative humidity of 60% was prepared according to Example 1. The H ₂ S was in this case a test gas cylinder (Messer Griesheim GmbH, Krefeld, Germany), the moistening was carried out by means of a gas washing bottle filled with distilled water, and the gas mixture thus produced was passed through a quartz glass measuring cuvette in which a PBA co-PHEA / PDMS sensor chip was attached in such a way that it was irradiated vertically from the measuring beam of a UV / VI S spectrophotometer.

The periodic recording of transmission spectra revealed a very rapid change in the transmission spectrum of the PBA-co-PHEA - / - PDMS sensor chips as a decrease in transmission at wavelengths below 550 nm (Figure 11). When the change in transmission at a wavelength of 325 nm was plotted against time, an approximately linear curve was obtained in the initial region, the slope of which depended on the H ₂ S concentration and thus could be used to calibrate the sensor (FIG. 12). Example 4: Sensor for integrative detection of low concentrations of nitrogen dioxide in gaseous samples

Surface functionalization of glass slides:

As in Example 1.

Synthesis of polymer networks:

As in Example 1.

Chemical modification of the polymer networks:

As in Example 1.

Loading the Polymer Networks with Indicator Reagent:

The PHEA - / - PDMS-coated glass slides were for about 30 ¹ diphenylamine min in a solution of 20 mg ^• ml ^"(Figure 13; Aldrich, Steinheim, Germany..) In chloroform (pa) shaken and, after brief drying in room air The back side of the coated glass slide was cleaned of diphenylamine residues with a cotton swab soaked in chloroform, then the transparent PHEA / PDMS coated and diphenylamine loaded glass slides were dried in room air for about half an hour.

Use as sensor:

The PHEA / PDMS coated and diphenylamine loaded glass slides (PHEA / PDMS diphenylamine sensor chips) were excellently suited for integrative detection of low concentrations of nitrogen dioxide (NO ₂ ) in gaseous samples. For this purpose, a gas mixture of 100 volume ppb NO ₂ in air with a volume flow of 1000 ml ^■ min ^'1 and a relative humidity of less than 5% was prepared according to Example 1. The gas mixture was passed through a desiccator in which the PHEA / PDMS diphenylamine sensor chips were in convection-induced convection in a protected polypropylene open box. The transmission spectra of the PHEA - / - PDMS diphenylamine sensor chips were recorded at the beginning of the fumigation and thereafter at intervals of several days using a UVΛ / IS spectrophotometer. This showed a marked change in the Transmission spectrum of the PHEA - / - PDMS-diphenylamine sensor chips to form a new transmission band at 390 nm (Fig. 14). By plotting the change in the transmission at this wavelength versus time, the result was an approximately linear curve over 3 weeks, the slope of which depended on the N0 ₂ concentration and thus could be used to calibrate the sensor (FIG. 15).

Example 5: Biosensor for detection of peroxides in organic solvents

Surface functionalization of glass slides:

Glass slides (76 × 15 × 1 mm ³ ) were placed in piranha solution (concentrated H ₂ SO ₄ in 30% H ₂ O ₂ , 3: 2) for 30 minutes, then rinsed with water, dried in air and placed in a 20 Vol .-% solution of 3-methacryloyloxypropyltrimethoxysilane in toluene. After 2 h sonication at room temperature, the slides were rinsed with water and dried in air for 16 h.

Synthesis of polymer networks:

The monomer mix for PHEA - / - PDMS films was prepared by adding Irgacure 651 photoinitiator (0.3 mg, 1.2 μmol) in freshly distilled trimethylsilyloxyethyl acrylate

(TMSOEA) (49.9 .mu.l, 45.9 mg, 244 .mu.mol) with shaking, added to MA-PDMS-MA (8.4 mg, 1, 62 .mu.mol) and shaken vigorously again. A polypropylene film was stuck to an unmodified glass slide, and 60 μl of the monomer mixture was uniformly applied thereto. Subsequently, a surface-functionalized glass slide was placed bubble-free on the monomer mixture and polymerized by irradiation with a UV polymerization lamp (Heraflash, Heraeus Kulzer) for 12 min. The polypropylene coated slide was then gently peeled off the surface-bonded amphiphilic network film.

Chemical modification of the polymer networks:

The amphiphilic network surface-bonded film was placed in a methanol / water mixture (90 ml, 1: 1). It was incubated at room temperature with shaking and with two changes of the solvent until no signals of the TMS protective group could be detected in the ATR-FTIR spectrum. Finally, the surface-bonded films were washed with 5 ml of methanol and dried in a drying oven (50 mbar, 60 ^° C.) until the weight remained constant. Loading the Polymer Networks with Indicator Reagent:

A surface-bound PHEA - / - PDMS film (1.5 cm ² ) was swollen overnight at room temperature in 0.1 M phosphate buffer (pH 7.0) and then in 2 ml of a solution of horseradish peroxidase (1 mg / ml) and 2 , 2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS, Fig. 16) (0.93 mg / ml, 1.7 mmol / l) in 0.1 M phosphate buffer (pH 7 , 0) and incubated at 4 ° C with gentle shaking overnight. The film was rinsed with 0.1 M phosphate buffer (pH 7.0) and dried under nitrogen.

Use as sensor:

The film was positioned in a cuvette in the beam path of a UV / VIS spectrophotometer. After addition of 3 ml of n-heptane, the absorption at 414 nm was measured over time. After 21 minutes, 5.45 .mu.l of a 5.5 M te / f-butyl hydroperoxide solution in decane were added and stirred vigorously for 30 s. The concentration of terf-butylhydroperoxide in the cuvette was 10 nM. A rapid increase in absorbance at 414 nm was observed (Figure 17).

The present invention thus makes available for the first time a sensor matrix which has a universally usable polymeric nanophase-separated network in which a multiplicity of different indicator substances and optionally additional enzymes can be incorporated and used. It is therefore also possible to form the sensor according to the invention as an array with sensor fields separated from one another, each individual field being provided with a different indicator substance, which then enables rapid and simultaneous measurement of a wide variety of noxious gases or of pollutants or other substances, and can also be automated.

Claims

claims

1. Sensor, in particular for the qualitative and / or quantitative determination of analytes in gaseous and / or liquid samples, comprising at least one polymeric material and at least one indicator substance, characterized in that the polymeric material is an at least two-phase, segmented polymer network, in which the at least one indicator substance is immobilized.

2. Sensor according to claim 1, characterized in that the polymeric material is segmented into nanophases with phase sizes in the range of 5 to 500 nm.

3. Sensor according to one of the preceding claims, characterized in that the polymeric material is amphiphilic.

4. Sensor according to one of the preceding claims, characterized in that the polymeric material has hydrophobic and hydrophilic units.

5. Sensor according to one of the preceding claims, characterized in that it has hydrophobic domains with a diameter in a range of about 5 to about 500 nm.

6. Sensor according to one of the preceding claims, characterized in that it has hydrophilic domains with a diameter in a range of about 5 to about 500 nm.

7. Sensor according to one of the preceding claims, characterized in that the component for producing a hydrophobic unit is selected from a group comprising alkyl (meth) acrylates, styrene, vinyl acetates, olefins, poly (ε-caprolactone), lactic acid, diisocyanates, diols , Diamines, diacids, polyactides, polypropylene fumarate, diglycidyl ethers of bisphenol A, polytetrahydrofuran and / or polyalkyloxazolines, perfluoroepolyethers and siloxanes and also their copolymers and / or macromonomers.

8. Sensor according to claim 7, characterized in that the component for producing a hydrophobic unit is a polydialkylsiloxane or polydiarylsiloxane macromonomer having a molecular weight M _n in a range of about 500 to about 1 million g / mol.

9. Sensor according to one of the preceding claims, characterized in that the component for producing a hydrophilic unit is selected from a group comprising as monomers (meth) acrylate and its derivatives, diisocyanates, diols, diamines, diacids, acrylamide, N-isopropylacrylamide, N-vinylcaprolactam, 2,3-dihydroxypropyl methacrylate, maleic acid, fumaric acid or vinyl acetate as monomers and / or as macromonomers, poly-1,3-dioxolane, polyethyleneimine, polypropyleneimine, polyethylene glycol, polypropylene glycol and polyoxazolines with (meth) acrylate, epoxy -, amino, isocyanato and / or hydroxyl end groups.

10. Sensor according to one of the preceding claims, characterized in that the polymeric material is insoluble in solvents.

11. Sensor according to one of the preceding claims, characterized in that the polymeric material is swellable in solvents.

12. Sensor according to one of the preceding claims, characterized in that the polymeric material is arranged on a carrier means.

13. A sensor according to claim 12, characterized in that the polymeric material is covalently bonded to the carrier.

14. Sensor according to one of the preceding claims, characterized in that the polymeric material is formed as a film.

15. Sensor according to claim 14, characterized in that the film is translucent.

16. Sensor according to claim 14 or 15, characterized in that the film is transparent and clear.

17. A sensor according to any one of claims 14 to 16, characterized in that the film has a thickness in a range of about 0.1 microns to about 1000 microns.

18. Sensor according to one of the preceding claims, characterized in that it is an optically evaluable sensor.

19. Sensor according to one of the preceding claims, characterized in that the indicator substance by van der Waals interactions, dipole-dipole change Effects, hydrogen bonds, ionic interactions and / or covalent bonds to the polymeric material is immobilized in this.

20. Sensor according to one of the preceding claims, characterized in that it comprises at least one immobilized enzyme.

21. A method for producing a sensor according to one of claims 1 to 20, characterized in that

- An at least two-phase, segmented polymer network is prepared by copolymerization of two macromonomers of different hydrophilicity or of a monomer and a macromonomer, each having different hydrophilicity; and

- The polymer network is loaded with at least one indicator substance.

22. The method according to claim 21, characterized in that the polymer network is further loaded with at least one enzyme.

23. The method according to any one of claims 21 or 22, characterized in that for the preparation of the polymer network, a hydrophobic macromonomer is reacted with a hydrophilic monomer.

24. The method according to any one of claims 21 to 23, characterized in that the polymer network is prepared by UV-initiated radical copolymerization.

25. Use of a polymeric material, which is formed as an at least two-phase, segmented polymer network and loaded with at least one indicator substance, as a sensor material.

26. Use of a sensor according to one of claims 1 to 20 for the qualitative and / or quantitative determination of analytes in gaseous and / or liquid samples.