FR2964104A1 - ULTRAMINAL LAYERS OF POLYMERS WITH CONFINED MOLECULAR IMPRESSIONS IN SURFACE OF A SUPPORT - Google Patents

Abstract

The present invention relates to ultrathin layers of molecular fingerprint polymers confined to the surface of a support, their methods of preparation and their uses.

Description

ULTRAMINAL LAYERS OF POLYMERS WITH CONFINED MOLECULAR IMPRESSIONS IN SURFACE OF A SUPPORT

The present invention relates to ultrathin layers of molecular fingerprint polymers confined to the surface of a support, their methods of preparation and their uses. Molecularly Imprinted Polymers (MIPs) have grown considerably since the 1990s. Their synthesis is carried out by crosslinking around an ionic, molecular or (bio) macromolecular model species, the elimination of which is possible. creating fingerprints having the shape and size of the model species used in their design. MIPs then become artificial receptors vis-a-vis the model species that has been used to nanostructure them and give them this "biomimetic" character. Among the published works relating to molecular imprinted polymers, mention may first be made of US Pat. No. 5,630,978, which discloses a method for the preparation of mimetics of a large variety of drugs, thanks to the use of MIPs whose Footprints were used for the polymerization of organic compounds with properties of similar size and shape to those of the model molecule. US5959050 discloses a method for preparing MIPs formed by two different acrylic monomers and at least one model molecule, in the form of uniform beads used in various screening techniques. Thus, the MIPs can be used in analytical chemistry for the detection and quantification of molecules of interest present in the trace state, the fixation of said analyte on said polymer resulting in the variation of a physical quantity (for example an electrical potential ) or chemical (for example a pH) whose measurement can be analyzed by a transducer and reported at an analyte concentration. The transducers employed are generally selected according to the type and concentration of the desired analyte and are, for example, selected from quartz crystal microbalances, surface plasmon resonance (SPR) sensors, optical sensors and acoustic sensors. Most of these systems and exemplary uses are described in Haupt K., Mosbach, K. (Molecularly Imprinted Polymers and Their Use in Biomimetic Sensors, Chem Rev. 2000, 100: 2495-2504). US Pat. No. 6,888,486 discloses MIP-coated quartz crystal microbalances and methods for their preparation, which are useful for on-line control of floating organic contaminants. However, these MIP-coated surface preparation techniques include tedious organic synthesis steps, otherwise inaccessible to the non-specialist, relatively long or that produce MIPs insufficiently confined to said surfaces. Confinement can however be improved by pretreatment of its surface, which consists in grafting on said surface functional groups initiating polymerization of MIPs or able to play this role after chemical transformation. For example, several publications disclose processes for preparing MIPs confined to gold surfaces by aromatic thiol groups grafted onto said surfaces. These aromatic thiol groups carry NO2 groups which can be reduced to NH 2 groups and subsequently attacked by malonodinitrile of formula CH3-CH (CN) 2, in order to obtain a surface grafted AIBN derivative capable of initiating an Atom Transfer Radical Polymerization (ATRP) polymerization. The thiol grafting step is however carried out in at least 72 hours. The publications of Geyer et al., Schmelmer et al., Wei et al., And that of Steenackers et al., Deal with this subject (Geyer et al., Electron-induced crosslinking of aromatic self-assembled monolayers: Negative resists for Applied Physics Letters, 1999, 75: 2401-2403, Schmelmer et al., Surface-Initiated Polymerization on Self-Assembled Monolayers: Amplification of Patterns on the Micrometer and Nanometer Scale, Angew Chem Int, Ed 2003, 42: 559-563, Wei et al., Molecular Imprinting by Atom Transfer Radical Polymerization, Biomacromolecules, 2005, 6 (2): 1113-1121, Steenackers et al., Morphology Control of Structured Polymer Brushes, Small 2007, 3: 1764-1773 ).

Another technique consists in using coupling silanes carrying an AIBN type photoinitiator group, as described in the publication by Prucker et al. (Synthesis of Poly (styrene) Monolayers Attached to High Surface Area Silica Gels through Self-Assembled Monolayers of Azo Initiators, Macromolecules, 1998, 31 (3): 592-601), or directly carriers of the model molecule around which will be synthesized MIP, as described in the publication of Zhang et al. (Novel surface modified molecularly imprinted polymer using acryloyl-beta-cyclodextrin and acrylamide as monomers for selective recognition of lysozyme in aqueous solution, Journal of Chromatography, A. 2009, 1216: 4560).

However, these confinements are not yet satisfactory and there is still a need for new methods to improve the confinement of the MIPs. The use of diazonium salts is known for the modification of surfaces (WO9213983; Pinson et al., Attachment of organic layers to conductive or semiconductive surfaces by reduction of diazonium salts, Chem Soc Rev. 2005, 34: 429-439), for photografting of preformed polymers (Adenier et al., Attachment of Polymers to Organic Moieties Covalently Bonded to Iron Surfaces, Chem., Mater., 2002, 14 (11): 4576-4585), surface photopolymerization leading to conventional polymers (WO2006000692 ), surface-controlled radical polymerizations (WO2006000692, Matrab et al., Novel approach for metallic surface-initiated atom transfer radical polymerization using electrografted initiators based on aryl diazonium salts, Langmuir, 2005, 21 (10): 4686-4694; Grafting densely-packed poly (n-butyl methacrylate) chains from an iron substrate by aryl diazonium surface-initiated ATRP: XPS monitoring.

Surface Science. 2007, 601: 2357-2366; Matrab et al. Growth of polymer brushes by atom transfer polymerization on glassy carbon modified by electro - grafted initiators based on aryl diazonium. Surface and Interface Analysis. 2006, 38 (4): 565-568; Matrab et al. Surface functionalization of ultrananocrystalline diamond using atom transfer radical polymerization (ATRP) initiated by electro - grafted aryldiazonium salts. Diamond & Related Materials. 2006, 15: 639-644; Matrab et al. Aryl Diazonium Salts for Carbon Surface-Initiated Fiber Atom Transfer Radical Polymerization. Journal of Adhesion. 2008, 84 (8): 684-701; Minh Ngoc Nguyen, et al. Protein-functionalized hairy diamond nanoparticles. Langmuir. 2009, 25: 9633-9636), as well as for electropolymerizations (Santos et al., Electrografting Polyaniline on Carbon through the Electroreduction of Diazonium Salts and the Electrochemical Polymerization of Aniline, Journal of Physical Chemistry C. 2008, 112 (41): 16103 -16,109). However, none of these publications mention the use of diazonium salts in combination with a surface-confined photopolymerization, especially a transducer surface, for the preparation of ultra-thin layers of molecular imprinted polymers, let alone the simplicity of implementation of such a system. The solution proposed by the inventors uses diazonium salts. which make it possible to very simply modify substrates (or supports), in particular transducers, with surface-initiating photopolymerization functional groups or capable of playing this role after chemical transformation. This method makes it possible in particular to detect molecules in the form of traces, that is to say concentrated at 1 nanomole / L, or even 0.1 nanomole / L. It also has an industrial advantage because of its simplicity of implementation and this at each stage of preparation of the sensitive layers of MIPs. For example, the cleaning of the plates prepared by this technique, carried out with the UV in the presence of ozone, lasts only a few minutes, while the chemical or electrochemical treatment for the grafting of the photoinitiators from the diazonium salts is carried out in a few minutes. minutes electrochemically, or in 20 to 30 minutes at most by chemical means. The electrochemical pretreatment of the substrates will therefore be preferred. Finally, it has been verified that polymer layers of 200 to 300 nm thick can be obtained after only 10 minutes of photopolymerization. For example, the methacrylic acid system (MAA, used as a functional monomer), ethylene glycol dimethacrylate (EGDMA, used as crosslinking monomer) and dopamine (model molecule), makes it possible to manufacture a dopamine-imprinted polymer in about 13 minutes.

These sensitive layers on the other hand have high stability, are easily regenerated and adhere to the surfaces without any sign of rupture. Also, the technique developed by the inventors makes it possible to detect (macro) molecules or ions of agri-food, biological, pharmaceutical and environmental interest. It can for example be exploited in the field of sport and the detection of doping products. It will also interest manufacturers wishing to provide custom prepared substrates for the specific detection of an analyte. This technique can also be exploited for the controlled release of drug substances by microelectrodes.

To carry out said MIPs, a functional monomer capable of producing covalent or non-covalent bonds (of the van der Waals and / or hydrogen bonding type) must be brought into contact with the model molecule studied ("template"), a monomer crosslinking for forming the three-dimensional network around the model species and a photoinitiator to initiate the photopolymerization reaction, and optionally a co-initiator complementary to the photoinitiator chosen. In order for the films to be generated on the surface of a support (for example an electrode), the photoinitiator must, according to the invention, be grafted onto the surface (directly or indirectly), which the diazonium salts make possible with a very strong membership.

Thus, the subject of the present invention is a process for preparing a molecular imprinted polymer confined to the surface of a support, said method comprising the following steps: a) a step of preparing said grafting surface on said surface polymerization initiator functional groups or able to play this role after chemical transformation, said functional groups being initially carried by diazonium salts and then grafted onto said surface by chemical or electrochemical reduction of said diazonium salts, b) optionally a step of chemical transformation of said graft groups on said surface to make them suitable for initiating a photopolymerization, c) a step of bringing the resulting surface into contact with a polymerization composition comprising at least one functional monomer, at least one crosslinking monomer, at least one model molecule, in a polymerization medium, d) a radical polymerization step induced by UV excitation of said composition from the grafts previously fixed on said surface, e) a step of obtaining an ultra-thin layer molecular imprinting polymer of a thickness less than or equal to at 1 μm, preferably less than or equal to 100 nm, more preferably less than or equal to 5 nm, f) a step of removing the at least one model molecule from the matrix of the molecular imprinted polymer, g) optionally the repeating steps a) to d) using a composition comprising at least one identical or different functional monomer, at least one identical or different crosslinking monomer and at least one identical or different model molecule. By "surface of a support" is meant the surface of a conductive or non-conductive substrate but activated by ultrasound, photons or even by microwaves. "Conductive substrate" means a conductive, semiconductor or conductive substrate. By way of nonlimiting examples of conducting substrates, mention may be made of pure metals or alloys, in particular iron, nickel, platinum, gold, copper, zinc, cobalt, titanium, chromium, silver, tantalum, especially stainless steels, titanium alloys, cobalt chromium alloys, molybdenum, manganese, vanadium and nitinol. By way of nonlimiting examples of semiconductor substrates, mention may be made of doped or non-doped silicon, mono- or polycrystalline silicon, hydrogenated silicon, tantalum nitride, titanium nitride, tantalum nitride and silicon carbide. , indium phosphide or gallium arsenide. Finally, as non-limiting examples of substrates made conductive, mention may be made of graphitized polymers on the surface.

As non-limiting examples of non-conductive substrates but activated by ultrasound, photons or even by microwaves, mention may be made of oxides, clays and polymers. In an advantageous embodiment, said "surface of a support" may contain different zones, each independently of the others being conductive, semiconductive, made conductive or non-conductive but activated by ultrasound, photons or by micro -ondes. By the expression "able to initiate a photopolymerization" is meant according to the present invention functional groups capable of forming the first species of a polymerase chain reaction, by reaction under UV excitation with a functional monomer, where appropriate in presence of a polymerization initiator. The expression "able to play this role after chemical transformation" means that it may be necessary to chemically transform said graft functional groups to make them able to initiate a photopolymerization according to the above definition. Said chemical route may comprise one or more stages, chosen by those skilled in the art.

According to the present invention, the term "diazonium salts" is intended to mean salts having the formula of the following general formula (I): X-N 2 + -A (1) in which: A represents a functional group initiator of polymerization or capable of playing this role after chemical conversion, X- represents an anion advantageously chosen from halides (I-, Br, Cl-), nitrates, sulphates, phosphates such as hexafluorophosphate, perchlorates, carboxylates and haloboranes, such as tetrafluoroborate. Tetrafluoroborate, which is known to lead to stable and non-explosive diazonium salts, will preferably be selected.

In an advantageous embodiment of the invention, the at least one functional monomer is chosen from compounds comprising at least one terminal double bond, for example vinyl compounds (acrylic, methacrylic, styrene) and in particular styrene, which is optionally substituted. , alkyl acrylates, substituted alkyl acrylates, alkyl methacrylate, substituted alkyl methacrylate, acrylonitrile, acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N dialkylacrylamide, N-dialkylmethacrylamide, isoprene, butadiene, ethylene, vinyl acetate and its derivatives, vinyl ethers, N-vinylpyrrolidone, 4-vinylpyridine, 3-vinylpyridine, 2-vinylpyridine, and in particular methyl methacrylate, ethyl methacrylate, propyl methacrylate and its isomers, butyl methacrylate and its isomers, 2-ethylhexyl methacrylate, isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenyl methacrylate, methacrylonitrile, methylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate and isomers thereof, butyl acrylate and its isomers, 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate, phenyl acrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate and its isomers, hydroxybutyl methacrylate and its isomers, N-dimethylaminoethyl methacrylate, 2- (diethylamino) ethylmethacrylate, triethyleneglycol methacrylate, itaconic anhydride, itaconic acid, benzylmethacrylate, 2- (dimethylamino) ) ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl isomers of acrylates, hydroxybutyl acrylate and isomers thereof, N-diethylaminoethyl acrylate, acyl triethylene glycol rylate, N-methylacrylamide, N, N-dimethylacrylamide, N-tert-butylmethacrylamide, N-n-butylmethacrylamide, N-methylolmethacrylamide, N-isopropylacrylamide, N-ethylolmethacrylamide, N-tert-butylacrylamide, N-butylacrylamide, N-methylolacrylamide, N-ethylolacrylamide, vinylbenzoic acid and its isomers, diethylaminostyrene and its isomers, methylvinylbenzoic acid and its isomers, diethylamino methylstyrene and its isomers, p-vinylbenzoic acid and its sodium salt, trimethoxysilylpropyl methacrylate, triethoxysilypropyl methacrylate, diisopropoxymethylsilylpropyl methacrylate, dimethoxysilylpropyl methacrylate, diethoxysilylpropyl methacrylate, dibutoxysilylpropyl methacrylate, disopropoxysilylpropyl methacrylate, trimethoxysilylpropyl acrylate, acrylate of triethoxysilylpropyl, tributoxysilpropyl acrylate, acryl dimethoxymethylsilypropylate, diethoxymethylsilypropyl acrylate, dibutoxymethylsilypropyl acrylate, diisopropoxymethylsilypropyl acrylate, dimethoxysilylpropyl acrylate, diethoxysilylpropyl acrylate, dibutoxysilypropyl acrylate, diisopropoxysilylpropyl acrylate, maleic anhydride , N-phenylmaleimide, N-butylmaleimide, butadiene, isoprene, chloroprene, 2- (2-oxo-limidazolidinyl) ethyl, 2-methyl-2-propanoate, N-vinyl pyrrolidone, N -vinyl imidazo le, 1- [2 - [[2-hydroxy-3- (2-propyl) propyl]] amino] ethyl] -2-imidazolidin-one, crotonic acid, vinylsulfonic acid and its derivatives 2-methacryloyloxyethylphosphorylcholine, phosphorylcholine type monomers, oligo (ethylene glycol) methacrylates, sulfatoethyl methacrylate ammonium salt, glyceromethacrylate, 2- (N-morpholino) ethyl methacrylate, and 2-methacryloyloxyethylphosphorylcholine; (N-3-sulfopropyl-N, N-dimethylammonium) ethyl methacryl ate, compounds having at least one vinyl function such as telechelic and α-tertbutoxy-β-vinylbenzyl polyglycidol (PGL). Similarly, in an advantageous embodiment of the invention, the at least one crosslinking monomer is chosen from divinylbenzene, ethyleneglycol dimethacrylate, tetramethyleneglycol dimethacrylate, poly (ethylene glycol) dimethacrylate, 2,2-bis ( hydroxymethyl) butanol trimethacrylate, N, N'-dimethylacrylamide, N, N'-ethylenebisacrylamide, 1,3-diisopropenylbenzene, 2,6-bisacryloylamidopyridine, N, N'-methylenediacrylamide, N, N ' 1,4-phenylenediarcylamine, 2,6-bisacryloylamidopyridine, N, O-bis (acryloyl) phenylalaninol, 1,4-di (acryloyl) piperazine and pentaerythritol tetraacrylate.

By the expression "model molecule" ("template", T) is meant an ionic, molecular, macromolecular species, organic or otherwise, around which the molecular imprinted polymer will be structured during the polymerization step.

In a preferred embodiment of the invention, the step of removing the at least one model molecule is carried out by extraction in a suitable solvent.

In a particularly advantageous embodiment of the process according to the invention, the diazonium salts are represented by the general formula (1), in which -A represents a type I or II photoinitiator group. By the term "type I photoinitiators" is meant compounds well known to those skilled in the art, capable of generating free radical initiators of polymerization under U.V excitation by intramolecular homolytic fragmentation.

Similarly, the term "free-radical type II photoinitiators" means compounds that are well known to those skilled in the art, capable of generating free radicals initiating polymerization by bimolecular reaction with another compound called a co-initiator, said reaction causing hydrogen to be transferred from the coinitiator to said type II photoinitiator.

The polymerization composition used in b) may therefore comprise, if appropriate, a co-initiator necessary for starting the photopolymerization, said co-initiator being preferably chosen from: ethyl-p-dimethylaminobenzoate, N, N-dimethylaniline (DMA) triethylamine (TEA), 4-dimethylaminobenzoate (EDAB), p-hydroxymethyl-N, N-dimethylaniline, N, N-dimethyltoluidine, p-methyl-N, N-dihydroxyethylaniline, dimethylaminoethanol, N, N-dimethylethanolamine, P-methyl-N, N-dihydroxyethylaniline and triethanolamine.

In yet another embodiment of the invention, the diazonium salts are represented by the general formula (2), which corresponds to the general formula (1) in which -A is a -phenyl-R group, as represented below: wherein R represents a substituent selected from the group consisting of: a hydrogen atom, linear or branched aliphatic radicals of 1 to 20 carbon atoms, optionally comprising one or more double or triple ( s) link (s), optionally substituted with carboxyl groups, NO2, OH, disubstituted protected amino, protected monosubstituted amino, cyano, diazonium, alkoxy of 1 to 20 carbon atoms, alkoxycarbonyl of 1 to 20 carbon atoms, alkylcarbonyloxy of 1 to 20 carbon atoms, optionally fluorinated vinyl or allyl, halogen atoms, ammonium groups comprising 1 to 20 carbon atoms, acid anhydrides comprising 1 to 20 carbon atoms, s of urea or thiourea comprising from 1 to 20 carbon atoms, oximes functions and phosphonic acids, aryl radicals optionally substituted by carboxyl groups, NO2, OH, disubstituted protected amino, protected monosubstituted amino, cyano , diazonium, alkoxy of 1 to 20 carbon atoms, alkoxycarbonyl of 1 to 20 carbon atoms, alkylcarbonyloxy of 1 to 20 carbon atoms, optionally fluorinated vinyl or allyl, the halogen atoms, ammonium groups comprising from 1 to 20 carbon atoms, acid anhydrides comprising from 1 to 20 carbon atoms, derivatives of urea or thiourea comprising from 1 to 20 carbon atoms, oxime functions and phosphonic acids, carboxyl groups, NO2, OH, disubstituted protected amino, protected monosubstituted amino, cyano, diazonium, alkoxy of 1 to 20 carbon atoms, alkoxycarbonyl of 1 to 20 carbon atoms, alkylcarbonyloxy of 1 to 20 carbon atoms, vinyl e optionally fluorinated, the halogen atoms, ammonium groups comprising from 1 to 20 carbon atoms, acid anhydrides comprising from 1 to 20 carbon atoms, derivatives of urea or thiourea comprising from 1 to 20 carbon atoms, oximes functions and phosphonic acids.

By way of nonlimiting example of an aliphatic initiator photopolymerization radical, there may be mentioned a radical chosen from: -C'H2'Br in which n varies from 1 to 4, and is preferably from 1 or 2, and a radical - CH (CH3) Br. In an advantageous embodiment of the invention, the group R of formula (II) is located in the para position of the group -N 2 +, so that the orientation of the growing polymer chains is close to the local vertical of said surface, as opposed to growing polymer chains whose orientation would be close to the surface itself. In a preferred embodiment of the invention, the diazonium salts used have the formula: BF 4 N 2 + -C 6 H 4 -CO-C 6 H 5.

The present invention also relates to a method according to the preceding definition, characterized in that the grafts mentioned in d) are chosen from the group comprising nitrophenyl, bromoalkyl phenyl and chloralkyl phenyl groups, and the type I or II photoinitiators comprising the benzyl, benzylic diketal and its derivatives, thioxanthone and its derivatives, 2,2-azobisisobutyronitrile, benzophenone and its derivatives, thioester type photoiniferters, dithioester and dithiocarbamate, quinones, irgacides, benzoin ethers, peroxides, 4-nitrobiphenyl, acetophenone derivatives, aniline, hydroxyalkylphenone and its derivatives, α-aminoketone and its derivatives and acylphosphine oxide, the formulas of which are given in Table 1 below.

Table 1 - Preferred Photoinitiators Names of Types Photoinitiator Formulas Nitrophenyl / -C6H4-NO2 Bromoalkyl Phenyl / -C6H4-CH (CH3) Br or -C6H4-CH2CH2Br Names of Types Chloroalkyl Phenyl / -C6H4-CH (CH3) Cl Formulas C6H4-CH2CH2C1 Benzil Type II (I ') OO _ 0 Benzyl diketal Type I in oo represent and its derivatives R and R' carbon. one independently of which OR 'a branched 1-6 alkyl chain of OR benzylic diketal: o of the other linear or atoms of: R = R' = H. Derivatives of Type II Ofl0R benzophenone in which: R represents H C1, a linear or branched alkyl chain of 1 to 6 carbon atoms or a phenyl group.

Types of Formulas Photoinitiator Formulas Derivatives of dithioesters Type IS R2 R1 in which: R1 represents H, a linear or branched alkyl chain of 1 to 6 carbon atoms or ether having 1 to 6 carbon atoms and R2 represents a linear alkyl chain or branched from 1 to 6 carbon atoms or a benzyl or NEt 2 group. : Preferably Et2 OS 2,2'-azobisisobutyronitrile Type INCN (AIBN) N Name of the Formula Quinone Photoameric Formulas Type II R 'OO - in which R and R' independently of one another represent a linear or branched alkyl chain from 1 to 6 carbon atoms. Quinone: R = R '= H. Irgacure 819 Type I ## STR3 ## wherein: R is -H, -Cl, -CH3, -C2H5, - (CH2) ) 3-CH3 or -CH (CH3) 2. Benzoyl Peroxide Type I ® oo Type Names Photoinitiator Formulas Such as: O OH SHOS Acetophenone Derivatives Type IOO \ CH3 CH 3 Aniline Type I () H2 Amino-biphenyl Type I H2 0 0 The term "photoiniferters" (abbreviation) "Photo-Initiator-Transfer-Terminators") are compounds well known to those skilled in the art, capable of acting as radical polymerization initiators, transfer agents and radical reaction terminators. The mechanism of action of these compounds is given in patent application EP0844256.

The diazonium salts employed in the context of the present invention may be prepared extemporaneously (Example 1) or in situ, in particular, from their amine precursors, and then reduced on a surface immersed directly in the medium used for their synthesis. The reduction of the diazonium salts generated in situ can, for example, be carried out without the addition of a solvent, by the addition of isoamyl nitrite and heating at 60 ° C. for 3 hours, according to the technique described by Li et al. (Functionalization of Single-Walled Carbon Nanotubes with Well-Defined Polystyrene by "Click" Coupling, J. Am., Chem Soc., 2005, 127 (41): 14518-14524).

It can also be made in an acidic medium according to the technique described by Baranton et al. (In situ generation of diazonium cations in organic electrolyte for electrochemical modification of electrode surface, Electrochimica Acta 2008, 53: 6961-6967), or as described by Corgier et al. (Diazonium-protein adducts for graphite electrode microarrays modification: direct and addressed electrochemical immobilization, J. Am Chem Soc 2005, 127: 18328). In addition to the grafting technique mentioned in Example 1, diazonium salts prepared extemporaneously can be grafted onto the surface by electrochemical reduction according to the following reaction: A + NX 2 + HX, NaNO 2 0 ° C or spontaneously in the presence of surfactant: HX, NaNO 2 0 0 C cw w H 2 SO 4 or Water + / Surfactant + NX 2 + R or spontaneously in the presence of acetonitrile: HX, NaNO 2 C + NX 2 ACN + 1h Yet another object of the present invention is a process according to one of the preceding definitions, characterized in that the functional monomer is selected from the group consisting of vinyl monomers, acrylic monomers, methacrylic monomers and mixtures thereof. By the term "mixtures thereof" is meant any mixture of at least two different monomers selected from the group of compounds mentioned above. Preferred functional monomers are given in Table 2 below. Table 2 - Preferred Functional Monomers Names of Preferred Functional Monomer Formulas Methyl H3C H 2 O OCH 3 Methacrylic O Methacrylic Acid H 3 C CH 2 -H 2 O / Methacrylamide 3 H 2 HH 2 O O Names of Preferred Functional Monomer Formulas Acrylamide <H2 H2, O Acrylic Acid II CH2 HO Styrene H2C / Boronic acid OH-OH-4-ethylstyrene H2C H3 Itaconic acid HC / -H- I p -H2C-H vinylbenzoic acid-4-vinylpyridine H2C N Names of preferred functional monomer formulations 1 -Vvinylimidazol H2 '~~~ NN α-tert-butoxy-β-vinylbenzyl-polyglycido (PGL) with n (OCHCH 2) n-OC (CH 3) 3 CH 2 OH ranging from 1 to 35. Yet another object of the present invention is a process according to any of the definitions characterized in that the crosslinking monomer is a member selected from the group consisting of divinylbenzene, ethylene glycol dimethacrylate, tetramethylene glycol dimethacrylate, poly (ethylene glycol) dimethacrylate, 2,2-bis (hydroxymethyl) butanol trimethacrylate, N, N'-dimethylacrylamide, N, N'-ethylenebisacrylamide, 1,3-diisopropenylbenzene, 2,6-bisacryloylamidopyridine, N, N 'methylenediacrylamide, N, 1,4-phenylenediarcylamine, 2,6-bisacryloylamidopyridine, N, O bis (acryloyl) phenylalaninol, 1,4 di (acryloyl) piperazine and pentaerythritol tetraacrylate. The preferred crosslinking monomers are given in Table 3 below.

Table 3 - Preferred Crosslinking Monomer Names of Monomers Preferred Crosslinking Formulas Ethylene Glycol H3C CH2 CH2 CH2 CH2 CH2 acrylate dimethacrylate Names of Monomers Preferred Crosslinking Formulas Tetramethylene H3C CH2 / CH2CH2 CH2 dimethacrylate CH2 CH2 Divinylbenzene H 2 C CH 2 1,3-diisopropenyl H 2 C CH 3 0 CH 3 benzene CH 2 2,6-bis H 2 HNH CH 2 acryloylamidopyridine NNN, N'-CH 2 CH 2 methylenediacrylamide HIHNN, N'-1,4-CH 2 HHO CH 2 phenylenediarcylamine NO, O-bisacryloyl CH2 N-OH 2 Phenylalanino Monomer Names Preferred Crosslinking Formulas 1,4-Diacryloyl H 3 O 2 CH 2 piperazine, ~ Pentaerythritol H2 ~ H2C CH 2 H 2 tetraacrylate CI- ~ The present invention also relates to a process according to the present invention. any of the preceding definitions, wherein the support is selected from the group consisting of porous and non-porous, planar and non-planar, inorganic and organic carriers. In another embodiment of the method of the invention, the support is in the form of plates or particles. In yet another embodiment of the process of the invention, the plates are chosen from the group comprising plates of gold, silicon, indium tin oxide, iron oxide, palladium oxide, copper oxide, nickel, zinc, doped and undoped diamond, vitreous carbon, carbon felt, carbon fiber, highly oriented pyrolytic carbon, mono- and multiwall carbon nanotubes and gallium arsenide.

In a particular embodiment of the process of the invention, the particles are chosen from the group comprising carbon black, mono- and multi-wall carbon nanotubes, graphene and undoped or doped diamond nanoparticles. nitrogen or boron, metal nanoparticles, in particular Au, Pt, Ru, Co, Al, Ni, Zn, Cu, bimetallic nanoparticles, in particular Pt-Ru, nanoparticles of oxides, in particular of silicon, of aluminum, of iron and magnesium, quantum dots based on cadmium sulphide or InAs / GaAs. In an advantageous embodiment of the method of the invention, the target molecule is chosen from the group comprising ions, antigens, antibodies, amino acids, peptides, proteins, nucleotides, DNA bases, drugs, pesticides, food products, heavy metals, pollutants, volatile and non-volatile organic compounds, and derivatives thereof. By the term "derivatives thereof" is meant derivatives of all the compounds mentioned above. The present invention further relates to a molecular fingerprint polymer having an ultrafine thickness confined to a support obtainable by the method according to any one of the preceding definitions. The present invention also relates to the use of at least one diazonium salt carrying photopolymerization initiator functional groups, as a photopolymerization initiator in a process for the preparation of molecular imprinted polymers, in ultrathin layers on a support, which are useful for the recognition of target molecules, said method comprising a step of photopolymerizing a composition comprising at least one crosslinking monomer, at least one functional monomer and at least one target molecule, the photopolymerization being confined to the surface of the support. The present invention also relates to chips comprising one or more molecular imprinted polymers having an ultra-thin thickness confined to a support, characterized in that the polymer (s) is (are) liable to be obtained by the method according to one of the preceding definitions. The subject of the present invention is also a kit for analyzing at least one target molecule comprising at least one molecular-fingerprint polymer obtainable by the method according to any one of Claims 1 to 9, said polymer being suitable interacting with the at least one target molecule, and at least one marker, said marker being able to interact with all or part of the recognition sites of the at least one target molecule.

The present invention also relates to the use of a molecular fingerprint polymer obtainable by the process according to any one of claims 1 to 9 for the recognition and / or extraction of target molecules. Figures 1 to 17 and Examples 1 to 4 below serve to illustrate the invention. Figure 1 shows the cyclic voltammetric (or voltammetry) diagram of the diazonium salt of 4-benzoyl phenyl in ACN + 0.1M Bu4BF4 on a plate of Au and ITO (ECS reference v = 0.2 Vs " ), obtained in the first scan cycle, and lb the second scan cycle.

FIG. 2 represents the chronoamperometry diagram on plates 2a of Au and 2b of ITO (respectively) in ACN + 0.1M of Bu4BF4 + 2mM of DZ. The reference is the saturated calomel electrode (SCE). Figure 3 shows the Polarization Modified Polarization Absorption Reflection (PM-IRRAS) spectrum of a BP grafted gold surface (Au-BP) and the IR spectrum of a KBr pellet of the diazonium salt. Figure 4 shows the wide-scan XPS spectra 4a of the BP-grafted glass carbon surface (CV-BP) and 4b of the BP-grafted gold surface (Au-BP). FIG. 5 represents the Cls spectra of a 5b surface area of glassy carbon and 5b of gold, grafted with BP (CV-BP and Au-BP).

Figure 6 shows the general XPS spectrum of the Au-nu, Au-BP and Au-MIP samples. Figure 7 shows the XPS C 1 s spectrum of the Au-BP and Au-MIP samples. Figure 8 shows the general XPS spectrum of an ITO-nu and ITO-MIP sample, and 8b the XPS Cls spectrum of an ITO-MIP sample. Figure 9 shows the PM-IRRAS spectra of Au-BP and Au-MIP. Figure 10 shows the AFM images for Au-nu, Au-BP and Au-BP-MIP. Figure 11 schematizes the steps of formation of MIPs with dopamine as the model molecule and the step of analysis by cyclic voltammetry.

Figure 12a shows the electrochemical response of dopamine immobilized on the Au-MIP electrodes compared to non-Au-NIP impregnated electrodes. Figure 12b is a histogram showing the influence of the model (T) / functional monomer (MF) / crosslinking monomer (MR) ratio on the anodic response.

Figure 13 shows the electrochemical responses obtained during the study of the specificity of the ITO-MIPs system. Figure 14 shows the electrochemical responses (cyclic voltammetry) of MIP-dopamine (MIP-DOP), non-impregnated polymer (NIP) and MIP-L-3,4-dihydroxyphenylalanine (MIP-L-dopa).

Figure 15 shows the electrochemical response of dopamine to the gold plates and 15b the linearization of this response according to the logarithmic concentration of dopamine from 10 -4 to 10 7 M. Figure 16 shows the electrochemical response obtained for the ITO-MIP system with a formulation T / MF / MR = 2/8/30 and 16b the linearization of this response Figures 16c and 16d represent the same variables for a formulation T / MF / MR = 2/8/25 Figure 17 shows the Square Wave Stripping Voltammetry (SWSV) voltammetry diagram for the detection of dopamine by ultrathin layers of MIPs.

EXAMPLE 1 EXTEMPORANEOUS SYNTHESIS OF THE SALT OF DIAZONIUM + N2-C6H4-CO-C6H5 (DZ) The tests were carried out with salts having as counterion X "= BF4 The starting diazonium salt (BF4-N2 + -C6H4-CO -C6H5) was synthesized from 4-amino-benzophenone, according to the method described by Pinson et al (Attachment of Polymers to Organic Moieties Covalently Bonded to Iron Surfaces, Chem Mater 2002, 14 (11): 4576- This salt (DZ) is suitable for surface photopolymerization since free benzophenone initiates photopolymerization in solution, as described by Dyer and Kato et al (Dyer, DJ Adv Polym Sci, 2006). 47: 197, Kato, E. et al, Prog Polym Sci, 2003, 28: 209-259) This salt is then reduced electrochemically on the carbon plates to be able to determine the optimal conditions of grafting which were then transposed to substrates of gold, silicon, 316L steel, ITO, etc. Plates modified by the 4-benzoyl group phenyl (BP) served as surface-initiated polymerization photoinitiator (surface-initiated photopolymerization, SIPP). In a flask placed in an ice bath, 17 mmol of 4-aminobenzophenone dissolved in 11.5 ml of tetrafluoroboric acid (HBF4, 48%) was added.

The mixture was kept stirring. The temperature having reached -3 ° C., 34 mmol of sodium nitrite (NaNO2 dissolved in a minimum of water) were added dropwise. An orange-brown precipitate appears. Stirring is maintained for 30 min at -3 ° C and then the solution was placed in the refrigerator overnight to precipitate the diazonium salt. After filtration of the sintered glass solution, the product was washed with pure water and cold diethyl ether and dried under vacuum. The powder obtained is brown in color; it was characterized by 1H NMR HHB4 4B (DMSO): 8 ppm: 8.87 and 8.25 (d, 4H), aromatic group of the diazonium salt, 7.5 to 7.8 (m, 5H aromatics) .

EXAMPLE 2 PREPARATION AND CHARACTERIZATION OF THE SURFACE TO BE POLYMERIZED 1. Electrochemical grafting of the aryl groups of DZ (+ N2-C6H4-CO-C6H5) on the surface The gold plates and ITO (Aldrich® 1 cm × 2 cm) obtained in Example 1 were washed with distilled water and ethanol and then cleaned with UV / 03 (3 cycles of 10 min). This step makes it possible to eliminate the superficial organic matter.

The reactions were carried out on glassy carbon electrodes and then transposed on a gold plate and ITO (FIGS. 1a and 1b). Two irreversible, broad, single-electron waves are observed at Epc = -0.366 V / SCE and -0.180 V / SCE corresponding respectively to the concerted reduction of the diazonium salt to aryl radical which reacts respectively with the surface of gold and ITO . During successive scans, the height of this wave becomes very low as is usual with the diazonium salts, the surface being progressively blocked by the grafting of aryl groups. The photoinitiator derived from the diazonium salt was then grafted by chronoamperometry at -0.700 V / SCE (or at -0.400 V / SCE for ITO). At the beginning, a large current is observed for a few seconds, which tends very rapidly towards zero (Figures 2a and 2b). This drop explains the cessation of the reduction process due to an organic film deposited on the surface and which reflects a blockage of the electrode, resulting in a weak current, a sign of passivation. Chromoamperometry will be used for systematic grafting studies of MIPs and their use for analyte detection. After grafting, the plates are carefully rinsed in acetonitrile (ACN) under ultrasound to remove molecules that are only physically adsorbed on the surface. The electrodes were then stored under an inert atmosphere to protect them from external contamination. 2. Characterization of the grafted surface by IR spectroscopy The IR spectrum obtained is given in FIG. 3. The most striking difference between the spectrum of the diazonium and the spectrum of the grafted organic layer is the absence of the band at 2228 cm. 1 indicating that the diazonium has been well reduced and is not only adsorbed on the surface. PM-IRRAS analysis of phenyl benzoyl-grafted plates clearly shows the appearance of the aromatic group signature with the cycle vibration at 1600 cm -1 and bands in the 3060 cm-1 characteristically CH elongation zone. aromatic groups. The appearance of a peak at 1650 cm-1 characteristic of the vibrational mode of v (C = 0) of the ketone function and the band at 1270 cm-1 which corresponds to the vibration of v (CC) conjugated confirms the presence of the initiator (-C6H4-CO-C6H5) on the surface. 3. Characterization of the XPS Grafted Surface The results are shown in Figures 4a and 4b. The spectrum contains the characteristic lines Au4f, Cls, N 1 s and Ois, centered respectively at 84, 285, 400 and 532 eV. As can be seen previously, the gold spectrum has very attenuated characteristic lines, but an intense continuous background which indicates a good coverage of the plates by a layer of photopolymerization initiating aryl groups whose thickness is 1 μm. order of 3 ± 1 nm in accordance with the literature. With regard to carbon, the high intensity ratio of 01 s / C 1 s is a good indication of the success of electrografting on vitreous carbon. The corresponding C 1 s spectra are given in Figures 5a and 5b. The gold plate has a high resolution Cls peak of the initiator (Figure 5b) which is reconstructed with four components. The assignment of these components to chemical functionalities as a function of the binding energy is as follows: a component centered at 285.0 eV corresponding to the carbon of type CC / C-H, characteristic of the carbons of diazonium salts; a component centered at 286.5 which groups together the C-O bond (due to the superficial oxidation of the aryl layers) and C-N due to the formation of azo bridges between the aryl groups (aryl-N = N-aryl). Indeed, it is well known that diazonium salts very generally lead to graft oligomers and not to monomolecular monolayers; a component centered at 287.9 corresponding to the carbon atom of the ketone function (C = O) of the initiator; a high energy link component centered at 291.9 ± 0.2. The latter, the satellite line of the main peak centered at 285 eV and called "skake up i-> n *", is specific to aromatic compounds. In the case of the CV-BP macroinitiator, the line C1s is decomposed into 5 contributions centered at 284.8; 285.3; 286.7; 287.9 and 291.5 eV respectively attributed to the C-C / C-H bonds of the aromatic carbon atoms, the Csp3, C-O, C = 0 and shakeup type carbons. It can be concluded from these two spectroscopic techniques that the 4-benzoyl phenyl (BP) group was grafted onto the gold and CV plates.

The contact angle measurements of the drops of water gave a value of 72 °. Photoinitiator aryl groups from other diazonium salts, postmodification polymerization photoinitiator groups, as well as aryl groups not having the function of photoinitiating the polymerization, but entering the general process of photopolymerization when a free photoinitiator solution is employed, have also been grafted. The following characteristics have been obtained.

For the diazonium salts of general formula (II): For R = - (CH2) 11-CH3 XPS has obtained an intense peak Cls centered at 285 eV and a strong attenuation of the gold signal. The presence of nitrogen reflects the presence of azo bridges. Infrared spectroscopy shows the disappearance of the N2 signature (expected at about 2200 cm-1), demonstrating that the covalent grafting took place. A strong signal detected around 2900 cm -I is attributed to the vibrations of CH2 groups. The drops of water make an angle of 92 ° with the surface which indicates a hydrophobic character that confers the long alkyl chain on the surface.

For R = -CH (CH3) Br, a peak Br3d centered at 70eV due to the C-Br bond was obtained by XPS, a Cls line at 285 eV with a shoulder at approximately 286 eV (C-Br bond) and that a strong attenuation of the signal of gold. The presence of nitrogen reflects the presence of azo bridges. Infrared spectroscopy shows the disappearance of the N2 signature (expected at about 2200 cm -1), demonstrating that the covalent grafting took place; a strong signal around 2900 cm 1 due to the vibrations of CH2 groups. The drops of water make an angle of 57 ° with the surface.

The -CH (CH 3) Br group was then modified with sodium N, N-diethyldithiocarbamate to obtain on the surface the C 6 H 4 -CH (CH 3) -S-C (= S) -N (C 2 H 5) 2 iniferter. The presence of sulfur by XPS (S2p at about 162-163 eV) can be noted. Infrared spectroscopy shows S-C = S and N-SCS bands around 1005 and 1560 cm-1, respectively. The -CH (CH 3) Br functional group can be replaced by the -CH 2 Br or -CH 2 CH 2 Br functional group and proceed in the same manner by using sodium N, Ndiethyldithiocarbamate or a derivative product to obtain a photoinitiator for controlled growth at the surface ( in thickness) layers of MIPs.

For R = -NO2 an XPS peak was obtained by XPS centered at about 406 eV from the nitro group and another at 400 eV due to the azo bridges. We notice a strong attenuation of the signal of the gold. Infrared spectroscopy shows the disappearance of the N2 signature (expected at about 2200 cm-1), demonstrating that the covalent grafting took place. The symmetrical and anti-symmetric bands of NO2 appear at about 1350 and 1520 cm -1, respectively. The NO2 group was then electrochemically reduced to -NH2 (a single peak in XPS centered at 400 eV). The amine group was attacked by CH3-CH (C = N) 2 (malonodinitrile) (Steenackers et al., Morphology control of structured polymer brushes, Small 2007, 3 (10): 1764-1773) to obtain the N = N group. -CH (C = N) 2 CH 3 bonded to phenyl from the starting diazonium salt (BF 4 "N 2 + -C 6 H 4 NO 2) The group -C 6 H 4 -N = N-CH (C = N) 2 CH 3 bonded to the substrate is equivalent to AIBN and allows to photoinitiate the surface polymerization.

It is also possible to limit oneself to obtaining -C6H4-NH2 and to conduct a photopolymerization leading to MIP by adapting the method of Steenackers et al. (Structured and Gradient Polymer Brushes from Biphenylthiol Self-Assembled Monolayers by Self-Initiated Photografting and Photopolymerization (SIPGP), Langmuir, 2009, 25: 2225). More simply, it has been verified that the grafting of -C6H4-NO2 aryl groups makes it possible to directly initiate surface photopolymerization.

For R = -SH, this diazonium salt was used to immobilize on the surface, gold nanoparticles (AuNP) as described by Porter et al. (Attachment of Gold Nanoparticles to Glassy Carbon Electrodes via Mercaptobenzene Film J Am Chem Soc 2001, 123: 5829-5830). A new substrate-aryl-AuNP interface is thus created on which it is possible to graft a new layer of photo-initiator aryl groups described above to initiate the formation of MIPs. This approach to the preparation of MIPs in the presence of AuNPs is similar to that described by Matsui et al. (SPR Sensor Chip for Detection of Small Molecules Using Molecularly Imprinted Polymer with Embedded Gold Nanoparticles, Anal Chem 2005, 77: 4282-4285) to obtain layers of MIPs useful in SPR detection of small molecules. For electrochemical detection, Xu et al. (A nanoparticles, Talanta, 2009, 78:26) have immobilized gold NPs on mercaptosilanes prior to photopolymerization of a prepolymer containing the molecule (A novel molecularly imprinted sensor for selectively probing imipramine created on ITO electrodes modified by nanoparticles. model. However, we can note in this work the absence of covalent bond between the MIPs and the surface, so unlike our method which has precisely the advantage of robustness of the anchoring layers of MIPs to surfaces.

EXAMPLE 3 GROWTH OF MOLECULAR IMPRINTED POLYMERS FROM ARY GRAFTS AND CHARACTERIZATION OF THE SURFACES CARRYING THE POLYMERS MIPs are grown on the surface by photopolymerization from the aryl grafts obtained in Example 2 and used as photoinitiators. 1. Photopolymerization In various cells, a solution containing the template molecule ("template"), a functional monomer (eg, methacrylic acid or 4-vinylpyridine (VP)), a crosslinking monomer, has been introduced. ethylene glycol dimethacrylate or EGDMA, methanol as a pore-forming solvent and N, N-dimethylaniline (DMA) as a hydrogen donor. The solution is purged with a stream of nitrogen (N2) to flush the oxygen for 10 to 15 minutes. Gold plates (or ITO, Si (111), 316L stainless steel, vitreous carbon, micro and nanoparticles modifiable by diazonium salts or amino precursors, etc.) grafted by the initiator are covered by this solution, under an atmosphere of nitrogen, then placed inside a reactor (spectro-LINKERTM, 17.6 mW / cm 2 at 365 min), then exposed to the irradiation source for 1000 seconds at room temperature. After irradiation, the plates are recovered and then immersed in a Erlenmeyer flask containing methanol to extract unreacted monomer. The plates are then dried and stored under nitrogen for analysis. The non-reactive reference plates were prepared in the same way, but this time in the absence of the target molecule, which leads to the non-imprinted polymer (NIP). The model molecules were extracted using the "Soxhlet" to obtain MIPs. The body of the Soxhlet containing the plate is fixed on a solvent tank (acetone in which the molecule is soluble) and is surmounted by a coolant. The solvent is vaporized and then condensed and remains in contact with the plate. The solution is drawn off periodically by priming a siphon. The solution of the balloon is gradually enriched in solute and the solid is always brought into contact with freshly distilled solvent. The extraction time is 24 hours. The model molecule can also be extracted by cyclic voltammetry, which is an alternative method to solvent extraction. In this case, after about 30 redox cycles between -200 and 1000 mV, dopamine oxidation peak is no longer observed, indicating that it has been fully extracted from the polymer. This extraction naturally leaves the molecular fingerprints of dopamine and the film can then be used to detect it. With a scanning speed of 100 mV / s, about thirty cycles require only 10-12 min to extract the model molecule, which represents a considerable time saving compared to the "Soxhlet" method (24h). 2. Characterization of Molecular-imprinted Polymer-coated Surfaces by XPS The wide-scan XPS spectra of bare and grafted gold plates are shown in Figure 6. The main lines Au4f, Cls and 01s are centered at, respectively, 84, 285 and 532 eV. One can also see the nitrogen Nis line at 400 eV (however dozens of accumulations of spectra) which reflects the incorporation of 4-vinylpyridine in the crosslinked copolymer. The modification of the gold by electrografting is very clear: we observe a significant increase in the intensity of the lines C 1 s and 01 s compared to those of the peaks of gold. For the Au-MIP sample, in situ grafting of the polymer completely obscures the gold substrate. However, the atomic% of the surface nitrogen is low (generally around 1%) because in the synthesis medium the 4-vinylpyridine generally represents only 20% at most of the "model molecule" mixture. MF / MR. In addition, the N / C ratio in this functional monomer (4-VP) is only 1 / 7th, which ultimately leads to a very low proportion of nitrogen in the MIP film. The high-resolution Cl s spectrum of Au-MIP (Figure 7) has components centered at 289, 286.5 and 285 eV which respectively characterize the carbon atoms OC = O and CO and CC: the carbon signal is in agreement with the chemical structure of the MIP which is here dominated by the EGDMA motifs, with in particular a line centered at 289 eV corresponding to the ester groups. As has been shown previously, the line Nls is very weakly intense compared to the lines C ls and Ois.

For Au-BP: the C = 0 component (288 eV) of the C 1 s line reflects the electrografting of the aryl groups derived from the diazonium salt. The 291-292 eV satellite is a proof that the electrografted species is aromatic. FIGS. 8a and 8b respectively represent the general XPS spectrum of an ITO-naked and ITO-MIP sample (ITO-BP-MIP), and the XPS C 1 s spectrum of an ITO-MIP sample. There can be observed a shielding of the signals of the ITO and the obtaining of intense lines C 1 s and Ols reflecting a passage of an inorganic substrate to an organic coating. The polymer is characterized by a C1 s line characteristic of a polymethacrylate as observed on a gold substrate.

This approach has also been extended to Si (111), 316L stainless steel and glassy carbon substrates. Assays were also performed on carbon microparticles and on carbon nanotubes modified by the aryl groups BP grafted by in-situ generation of diazonium salts from aminobenzophenone in the presence of isoamyl nitrite. The set of results indicates attenuation of the signals of the substrate and the appearance of peaks Cl s and O 1 s characteristic of the ester function of EGDMA. 3. Characterization of Molecular Impregnated Polymer-coated Surfaces Figure 9 presents the Au-BP and Au-MIP spectra. The most remarkable difference between the two spectra is the appearance, after the polymerization step, of a very intense band at 1735 cm -1, which signifies the presence of the polymer by its pendant carbonyl group. The appearance of bands at 1261 and 1167 cm -1, corresponding respectively to v (C = O) and v (C-O-C), reflects the successful growth of poly (EGDMA) at the surface.

The small peak located at 1632 cm-1 characteristic of the vibration v (C = C) is weak compared to that of the v (C = O) of grafted EGDMA. This shows that EGDMA has polymerized via these two C = C double bonds. The distinction of the characteristic peaks of the MAA units from those of the EGDMA units is difficult for two reasons: on the one hand the copolymer was prepared with a molar ratio EGDMA / MAA is 30/8, hence the dominance of the EGDMA motifs at the area. On the other hand, the spectral signatures of the MAA and EGDMA patterns are very similar.

In contrast, the small broad band at about 3300 cm-1 reflects the presence of the MAA functional monomer in the MIP. 4. Characterization of molecular imprinted polymer-coated surfaces by AFM Figure 10 shows images obtained by AFM on Au, Au-BP, Au-MIP plates. The image shows that the morphology of the gold surface is significantly modified by the grafting of the initiator and the consequent polymer coating. The maximum height increases in the Au <Au-BP <Au-MIP direction. It may be noted that the Au-MIP surface has a spongy appearance which could allow a better diffusion of the analytes to the metal-polymer interface where they will be detected electrochemically.

EXAMPLE 4: ELECTROCHEMICAL DETECTION OF DOPAMINE AND STUDY OF THE SPECIFICITY OF SAID DETECTION 1. Electrochemical Detection of the Model Molecule (Dopamine) Cyclic voltammetry makes it possible to study the detection of the model molecule by the MIPs and to establish whether these latter are very specific and selective. For this purpose, the electrodes obtained in Example 3 are immersed in the solution of dopamine (or L-dopa, an interferon) for 20 minutes, then rinsed with a PBS solution (phosphate buffer saline solution, pH 7.4). to eliminate all physisorbed molecules. Dopamine trapped by artificial receptors is characterized by an irreversible wave when a potential is applied between -0.3 and 0.9 v in a PBS solution (0.1 M, pH = 7.4) as shown in Figure 11. 2 Specificity Study on Au and ITO Figure 12a shows the electrochemical response of dopamine immobilized on the Au-MIP electrodes compared to non-Au-NIP impregnated electrodes. The difference is very significant and proves the specificity of these electrodes vis-à-vis the target molecule.

Modification of the ratio of model molecule or template (T), functional monomer (MF); Crosslinking monomer (MR): T / MR / MF acts on the electrochemical response; therefore, the more artificial receptor sites, the better the anodic response (Figure 12b). The same experiment was transposed on ITO (inexpensive surface compared to gold plates). Figure 13 confirms that the concept works on various surfaces and clearly demonstrates the specificity of ITO-MIP. The electrochemical response of NIP (unprinted surface) is almost the same as that of naked ITO. 3. Study of the selectivity on Au The selectivity of Au-MIP with respect to dopamine was studied by comparing the oxidation waves of dopamine and L-dopa, after incubation for 20 minutes, in the solutions of respective catechols. L-dopa was chosen because of its resemblance (chemical composition and form) to dopamine. Figure 14 shows the electrochemical response (cyclic voltammetry) of the "dopamine-templated" film after incubation in a solution of 0.1 M PBS (pH 7.4) of L-dopa or dopamine. A very low oxidation current was observed for L-dopa, as in the case of an Au-NIP surface. No recognition of L-dopa by dopamine cavities. Electrochemical response: anodic current (L-dopa) = anodic current of NIP. These results highlight the selectivity of MIPs. 4. Detection threshold The detection threshold was first determined on the Au plates and then on the ITO plates.

Figure 15 shows a detection limit better than 10-7 M on the gold plates and also a linear variation of the current with the logarithmic concentration of dopamine from 10-4 to 10 M. The detection threshold and the effect of the formulation were also studied on ITO.

Figure 16 shows the (logarithmic) relationship between the intensity of the dopamine oxidation current and its solution concentration, i.e., in the medium in which the grafted MIP plates are incubated. This relationship is linear over a wide range of concentrations, between 10-9 and 10 -4 M. The formulation T / MF / MR = 2/8/30 gives better detection at low concentration of the analyte compared to the formulation 2/8/25 The latter gives a better detection at high concentration of the analyte (dopamine) The limit of detection of analytes by cyclic voltammetry being of the order of 10-8 mol or better, this threshold was lowered at 10-9 mol or better using Square Wave Dissolution Voltammetry (SWSV) which is said to be more sensitive for analytical aspects of electrochemistry (Gam-Derouich et al., Aryl diazonium knows surface chemistry and ATRP for preparation Surfact Anal Analogue 2010, 42 (6-7): 1050-1056) Figure 17 shows that starting from a dopamine concentration equal to 1 nanomole, SWSV still allows to detect an electrochemical signal at the oxidation potential dopamine.

Claims (14)

REVENDICATIONS1. A process for the preparation of a molecular imprinted polymer confined to the surface of a support, said method comprising the following steps: a) a step of preparing said surface comprising grafting on said surface polymerization initiator functional groups or groups capable of play this role after chemical transformation, said functional groups being initially carried by diazonium salts and then grafted onto said surface by chemical or electrochemical reduction of said diazonium salts, b) where appropriate a step of transforming said grafted groups on said surface for to make it possible to initiate a photopolymerization, c) a step of bringing the resulting surface into contact with a polymerization composition comprising at least one functional monomer, at least one crosslinking monomer, at least one model molecule, in a polymerization medium, and ) a radical polymerization step induced by UV excitation of said composition from the grafts previously fixed on said surface, e) a step of obtaining an ultra-thin layer molecular imprinted polymer with a thickness less than or equal to 1 μm, preferably less than or equal to 1 μm, equal to 100 nm, more preferably less than or equal to 5 nm, f) a step of removing the at least one model molecule from the matrix of the molecular fingerprint polymer, g) optionally the repetition of steps a) to d) using a composition comprising at least one identical or different functional monomer, at least one identical or different crosslinking monomer and at least one identical or different model molecule. 2. Method according to claim 1, characterized in that the grafts mentioned in d) are chosen from the group comprising nitrophenyl, bromoalkyl phenyl and chloralkyl phenyl groups, and type I or II photoinitiators comprising benzyl, benzyl diketal and its derivatives, thioxanthone and its derivatives, 2,2-azobisisobutyronitrile, benzophenone and its derivatives, thioester type photoiniferters, dithioester and dithiocarbamate, quinones, irgacides, benzoin ethers, peroxides, 4-nitrobiphenyl derivatives of acetophenone, aniline, hydroxyalkylphenone and its derivatives, α-aminoketone and its derivatives and acylphosphine oxide. 3. Method according to any one of the preceding claims, characterized in that the functional monomer is a selected from the group consisting of vinyl monomers, acrylic monomers and methacrylic monomers and mixtures thereof. 10 4. Method according to any one of the preceding claims, characterized in that the crosslinking monomer is chosen from the group comprising divinylbenzene, ethylene glycol dimethacrylate, tetramethylene glycol dimethacrylate, poly (ethylene glycol) dimethacrylate, 2,2 bis (hydroxymethyl) butanol trimethacrylate, N, N'-dimethylacrylamide, N, N'-ethylenebisacrylamide, 1,3-diisopropenylbenzene, 2,6-bisacryloylamidopyridine, N, N'-methylenediacrylamide, N 1,4-1,4-phenylenediarcylamine, 2,6-bisacryloylamidopyridine, N, O-bis (acryloyl) phenylalaninol, 1,4-di (acryloyl) piperazine and pentaerythritol tetraacrylate. The method of any one of claims 1 to 4, wherein the support is selected from the group consisting of porous and non-porous, planar and non-planar, inorganic and organic carriers. 6. Method according to claim 5, characterized in that the support is in the form of plates or particles. 7. Process according to claim 6, characterized in that the plates are chosen from the group consisting of plates of gold, silicon, indium-tin oxide, iron, palladium, copper, nickel zinc, doped and undoped diamond, glassy carbon, carbon felt, carbon fiber, highly oriented pyrolytic carbon, mono- and mono-carbon carbon nanotubes and gallium arsenide. 8. Process according to claim 6, characterized in that the particles are chosen from the group comprising carbon black, mono- and mufti-wall carbon nanotubes, graphene and undoped or doped diamond nanoparticles. nitrogen or boron, metal nanoparticles, in particular Au, Pt, Ru, Co, Al, Ni, Zn, Cu, bimetallic nanoparticles, in particular Pt-Ru, nanoparticles of oxides, in particular silicon, aluminum, iron and magnesium, quantum dots based on cadmium sulphide or InAs / Ga.As. 9. Process according to any one of claims 1 to 8, characterized in that the target molecule is chosen from the group comprising ions, antigens, antibodies, amino acids, peptides, proteins, nucleotides, DNA bases, drugs, pesticides, food products, heavy metals, pollutants, volatile organic compounds or not, and derivatives thereof. 10. A molecular fingerprint polymer having an ultrafine thickness confined to a support obtainable by the method of any one of claims 1 to 9. 11. Use of at least one diazonium salt carrying photopolymerization initiator functional groups, as photopolymerization initiator in a process for the preparation of molecular imprinted polymers, in ultrathin layers on a support, useful for the recognition of target molecules, said method comprising a step of photopolymerizing a composition comprising at least one crosslinking monomer, at least one functional monomer and at least one target molecule, the photopolymerization being confined to the surface of the support. 12. Fleas comprising one or more molecular-fingerprint polymers having an ultra-fine thickness confined to a support, characterized in that the polymer (s) is (are) capable of being obtained by the process according to any one of claims 1 to 9. 13. Kit for analyzing at least one target molecule comprising at least one molecular imprintable polymer obtainable by the method according to any one of claims 1 to 9, said polymer being able to interact with the at least one a target molecule, and at least one marker, said marker being able to interact with all or part of the recognition sites of the at least one target molecule. 14. Use of a molecular fingerprint polymer obtainable by the process of any one of claims 1 to 9 for the recognition and / or extraction of target molecules.