1. A molecularly imprinted polymer nanoparticle with surface-grafted hydrophilic polymer brushes, wherein said nanoparticle has a core formed by the crosslinked polymer networks and hydrophilic polymer brushes on the surfaces of the core, said core has a crosslinking degree exceeding 50% and a particle diameter of 10-500 nm, and the core of said nanoparticle has molecularly imprinted cavities that are capable of recognizing the template molecules in biological samples.

2. The molecularly imprinted polymer nanoparticle according to claim 1, wherein said molecularly imprinted polymer nanoparticle is synthesized by a reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization of monovinyl functional monomer and crosslinker mediated by hydrophilic macromolecular chain transfer agent and optional small molecule chain transfer agent in the presence of template molecule.

3. The molecularly imprinted polymer nanoparticle according to claim 2, wherein said reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization is induced by the combined use of the hydrophilic macromolecular chain transfer agent and the small molecule chain transfer agent.

4. The molecularly imprinted polymer nanoparticle according to claim 2, wherein said template molecule is selected from the group consisting of amino acid, biological receptor, nucleic acid, steroid, immunosuppressant, hormone, heparin, antibiotics, vitamin, small pathological and disease biomarker, toxin, pesticide, herbicide, explosive, neurotoxin, endocrine disrupter, nucleotide, nucleoside, oligomeric nucleotide, metabolin, secondary metabolite, drug metabolite, drug, drug intermediate, and pharmic organic molecule.

5. The molecularly imprinted polymer nanoparticle according to claim 2, wherein said monovinyl functional monomer is selected from the group consisting of C2-C8 monoolefin, aromatic vinyl compounds, heterocyclic aromatic vinyl compounds, monoolefin type unsaturated carboxylic acid, carboxylate, ester and amide, vinyl alcohol and its ester, allyl alcohol and its ester, vinyl ether, vinyl lactam, vinyl halide, 1,1-dihaloethylene, (meth)acrylic acid and its ester, salt, amide, vinylpyridine compound, trifluoromethylacrylic acid and combinations thereof.

6. The molecularly imprinted polymer nanoparticle according to claim 2, wherein said crosslinker is a monomer with two or more nonconjugated unsaturated double bond.

7. The molecularly imprinted polymer nanoparticle according to claim 2, wherein said hydrophilic macromolecular chain transfer agent is hydrophilic polymers with a terminal dithioester or trithiocarbonate group.

8. The molecularly imprinted polymer nanoparticle according to claim 2, wherein said small molecule chain transfer agent has the following structure:



wherein R=alkyl, alkenyl, alkynyl, aryl, aralkyl, substituted alkyl, substituted aryl, carbocyclic or heterocyclic, alkyloxy or dialkylamine; Z=alkyl, aryl, aralkyl, substituted alkyl, substituted aryl, carbocyclic or heterocyclic, alkylthiol, arylthiol, alkoxycarbonyl, aralkoxycarbonyl, acyloxy, carbamoyl, cyano, N-alkyl, N-aryl-substituted amino, alkoxy, aryloxy, dialkyl or diaryl phosphate, dialkyl or diaryl phosphinic.

9. The molecularly imprinted polymer nanoparticle according to claim 2, wherein the molar ratio of the template molecule to monovinyl functional monomer to crosslinker is 1:1-10:4-80.

10. The molecularly imprinted polymer nanoparticle according to claim 2, wherein the molar ratio of the total amount of monovinyl functional monomer and crosslinker to that of the hydrophilic macromolecular chain transfer agent and optional small molecule chain transfer agent is 500:1-10:1.

11. The molecularly imprinted polymer nanoparticle according to claim 2, wherein the molar percentage of the small molecule chain transfer agent in the total amount of both small molecule chain transfer agent and hydrophilic macromolecular chain transfer agent is 0-95%.

12. The molecularly imprinted polymer nanoparticle according to claim 2, wherein the number-average molecular weight of said hydrophilic macromolecular chain transfer agent is in a range from of 500 to 50,000.

13. The molecularly imprinted polymer nanoparticle according to claim 1, wherein said molecularly imprinted polymer nanoparticle has a narrow particle size distribution, and the narrow particle size distribution indices of said nanoparticle determined by dynamic laser scattering according to ISO 13321 is less than or equal to 0.6.

14. The molecularly imprinted polymer nanoparticle according to claim 1, wherein said hydrophilic polymer brushes are formed by the macromolecular chain transfer agent.

15. A kit comprising the molecularly imprinted polymer nanoparticle with surface-grafted hydrophilic polymer brushes according to claim 1.

16. A sensor applicable for biological samples comprising the molecularly imprinted polymer nanoparticle with surface-grafted hydrophilic polymer brushes according to claim 1.

PRIORITY INFORMATION

[0001]This application is a 371 of PCT Application No. PCT/CN2013/087538 filed Nov. 20, 2013, which claims priority to Chinese Patent Application No. 201210470277.1 filed Nov. 20, 2012, both of which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

[0002]The present invention relates to molecularly imprinted polymer nanoparticles and a preparation method thereof, and it especially relates to molecularly imprinted polymer nanoparticles with excellent molecular recognition ability toward small organic molecules in biological samples, and in particular pure biological samples, and a preparation method thereof. To be specific, the present invention relates to molecularly imprinted polymer nanoparticles with surface-grafted hydrophilic polymer brushes and their one-pot preparation method.

BACKGROUND ART

[0003]In nature, the molecular recognition based on biological receptors (such as enzymes, antibodies, etc.) plays a decisive role in most biological processes (such as immune responses, ligand-receptor interaction, and enzyme catalysis). How to develop synthetic receptors with an affinity and specificity approaching those of biological receptors has been a significant challenge for the contemporary chemists. So far, many low molecular weight organic receptors have been prepared (F. Hof, S. L. Craig, C. Nuckolls, J. Rebek Jr., Angew. Chem. Int. Ed. 2002, 41, 1488-1508; D. M. Vriezema, M. C. Aragonés, J. A. A. W. Elemans, J. J. L. M. Cornelissen, A. E. Rowan, R. J. M. Nolte, Chem. Rev. 2005, 105, 1445-1490). The construction of such synthetic receptors, however, usually requires complicated multi-step synthesis, which severely limits their broad applications. Developing other synthetically more accessible receptors has become a hot research topic in recent years.

[0004]Molecular imprinting technique is a facile and efficient new method to prepare polymer receptors with specific molecular recognition sites (H. Zhang, L. Ye, K. Mosbach, J. Mol. Recognit. 2006, 19, 248-259). The molecularly imprinted polymers (simply MIPs) generated by this technique have attracted enormous attention due to their high specific molecular recognition ability, ease of preparation, and good thermal and chemical stability. In the present, molecular imprinting technique has become a straightforward and efficient way to obtaining biomimetic synthetic receptors. One of the most distinct characteristics of the molecular imprinting process is its generality, which offers the freedom to prepare MIPs for a wide range of templates without appreciably changing the synthetic protocols. So far, the application studies of the MIPs have been extended to many areas, including chromatographic stationary-phase, solid-phase extraction, immunoassays, biomimetic sensors, artificial enzymes, organic synthesis, and drug delivery. They have shown great potential for applications in the fields of food safety and environmental monitoring. The ultimate goal of the molecular imprinting study is to generate MIPs that are comparable with biological receptors, which can eventually replace the biological receptors in practical applications.

[0005]Despite the fact that significant progress has been achieved in the molecular imprinting field and some MIPs have become commercially available for some specific applications (e.g., solid-phase extraction), there still exist some key problems and challenges in this area, which significantly limits their broad practical applications. One of such challenges is how to prepare MIPs with excellent specific recognition ability toward small organic analytes (most of the environmental pollutants, drugs, antibiotics, pesticides, and herbicides are small organic molecules) in aqueous media. The previously developed MIPs that target small organic molecules normally only show good molecular recognition ability in organic solvents, and those truly compatible with aqueous samples are rather rare. It is, however, certainly worth replacing organic solvents with water from the viewpoint of many aspects such as economy, ecology, and environmental protection. In addition, it is definitely necessary to use water as the solvent for the potential application of the MIPs in the field of biotechnology. Furthermore, the use of MIPs capable of efficient molecular recognition in aqueous media can help achieve the goal of direct and rapid sensing of small organic analytes in their practical applications in such areas as environmental and food monitoring and clinical diagnostics. Although some advances have been made in this aspect by using specifically designed functional monomers (G. Wulff, R. Schöonfeld, Adv. Mater 1998, 10, 957-959; H. Asanuma, T. Hishiya, M. Komiyama, Adv. Mater 2000, 12, 1019-1030; P. Manesiotis, A. J. Hall, J. Courtois, K. Irgum, B. Sellergren, Angew. Chem. Int. Ed. 2005, 44, 3902-3906; J. L. Urraca, A. J. Hall, M. C. Moreno-Bondi, B. Sellergren, Angew. Chem. Int. Ed. 2006, 45, 5158-5161), by using traditional molecular imprinting method (L. I. Anderson, R. Müller, G. Vlatakis, K. Mosbach, Proc. Natl. Acad. Sci. U.S.A. 1995, 92, 4788-4792; J. G. Karlsson, L. I. Andersson, I. A. Nicholls, Anal. Chim. Acta 2001, 435, 57-64), or by adding hydrophilic co-monomers into the molecular imprinting systems (B. Dirion, Z. Cobb, E. Schillinger, L. I. Andersson, B. Sellergren, J. Am. Chem. Soc. 2003, 125, 15101-15109), the preparation of MIPs compatible with pure biological samples remains a challenging task in the present.

[0006]It is well known that biological samples, and in particular pure biological samples, have rather complex components (for example, biological samples such as milk and serum contain a large amount of proteins), which makes it very difficult for the MIPs to specifically recognize small organic analytes in real biological samples. It is noted that although there have been many reports on the application of MIPs as solid-phase extraction materials for the separation of target analytes in real biological matrices (B. Sellergren, Anal. Chem. 1994, 66, 1578-1582; E. Caro, R. M. Marcé, F. Borrull, P. A. G. Cormack, D. C. Sherrington, Trend. Anal. Chem. 2006, 25, 143-154; B. Tse Sum Bui, K. Haupt, Anal. Bioanal. Chem. 2010, 398, 2481-2492; E. Turiel, A. Martín-Esteban, Anal. Chim. Acta 2010, 668, 87-99), however, the selectivity of the MIPs in this case is mainly controlled by the washing solvents used in the extraction processes. This is much easier than the direct use of MIPs for the molecular recognition in real matrices, as the latter case is mainly fixed by the nature of MIPs (V. Pichon, F. Chapuis-Hugon, Anal. Chim. Acta 2008, 622, 48-61).

[0007]Recently, the inventors reported the one-pot synthesis of pure water-compatible MIP microspheres with surface-grafted hydrophilic polymer brushes through the introduction of hydrophilic macromolecular chain transfer agents into the reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization system (G. Pan, Y. Zhang, Y. Ma, C. Li, H. Zhang, Angew. Chem. Int. Ed. 2011, 50, 11731-11734). The MIP particles prepared by the above method, however, are of micrometer sizes, and in spite of their compatibility with normal aqueous samples, they cannot be used for the direct analyses of biological samples because of the significant adsorption of proteins in biological samples onto the surfaces of the MIP microspheres. Therefore, the inventors successfully prepared MIP nanoparticles with surface-grafted hydrophilic polymer brushes that are compatible with biological samples, and in particular pure biological samples in a one-pot method on the basis of the above work. The nanosized volumes imparted these hydrophilic MIP nanoparticles with excellent water dispersion stability, which paved the way for their applications in such areas as environmental monitoring, food safety, and clinical diagnostics.

SUMMARY OF THE INVENTION

[0008]The present invention aims to provide MIP nanoparticles compatible with biological samples, and in particular pure biological samples, and a preparation method thereof, in order to compensate for the defects of the existing technology and lay the foundation for the practical applications of the MIPs by their eventual replacement of natural receptors.

[0009]According to the concept of the present invention, MIP nanoparticles with surface-grafted hydrophilic polymer brushes and thus MIPs compatible with pure biological samples can be obtained by introducing appropriate hydrophilic macromolecular chain transfer agents into RAFT precipitation polymerization systems through the one-pot synthesis.

[0010]The detailed synthestic procedure of the present invention is described as follows:[0011](1) Dissolving the template molecule, functional monomer, and crosslinker into an appropriate solvent with their molar ratio being 1:1˜10:4˜80 and the volume percentage of the functional monomer and crosslinker in the whole reaction system being 0.5˜10%.[0012](2) Adding the initiator that is 0.5˜10% relative to the total amount of the functional monomer and crosslinker and appropriate amount of the chain transfer agent into the polymerization system, wherein the molar ratio of the initiator to chain transfer agent is 1:1˜20.[0013](3) The used chain transfer agent includes a small chain transfer agent and a hydrophilic macromolecular chain transfer agent, wherein the molar percentage of the small chain transfer agent is 0˜95%.[0014](4) After the complete dissolution of all the above reactants, the reaction mixture is degassed by being purged with argon or nitrogen for 5˜60 min to remove oxygen from the polymerization system, sealed, and then immersed into an oil bath with a temperature of 25˜100° C. and the polymerization is allowed to take place for 1˜100 h. After the ultrasonication of the reaction mixture for 5˜30 min, the polymer nanoparticles with entrapped template molecules are collected by high speed centrifugation.[0015](5) The resulting polymer nanoparticles are then washed with methanol/acetic acid (with a volume ratio of 10/0.1˜10/10) for 12˜72 h and methanol for 12˜48 h successively until no template molecules can be detected in the washing solution. After being dried at 20˜60° C. under vacuum to the constant weight, MIP nanoparticles with surface-grafted hydrophilic polymer brushes are obtained.

[0016]Said functional monomer is 4-vinylpyridine, 2-vinylpyridine, 4-vinylbenzoic acid, (meth)acrylic acid, trifluoromethyl acrylic acid, 2-hydroxyethyl methylacrylate, dimethylaminoethyl methacrylate, (meth)acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, 4-vinylimidazole, itaconic acid or N-vinylpyrrolidone.

[0017]Said crosslinker is ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, divinylbenzene, N,N′-methylenebisacrylamide, N,N′-ethylenebisacrylamide, N,N′-1,4-phenylbisacrylamide or 1,4-diacryloylpiperazine.

[0018]Said initiator is azo free radical initiator, peroxide free radical initiator, or redox initiator.

[0019]Said small chain transfer agent is dithioester or trithiocarbonate organic compound.

[0020]Said macromolecular chain transfer agent is selected from hydrophilic polymers with a terminal dithioester or trithiocarbonate group, wherein the polymer are polyethylene glycol, poly(N-isopropylacrylamide), poly(2-hydroxyethyl methacrylate), poly((meth)acrylamide), poly(N,N-dimethylacrylamide), or poly(N,N-dimethylaminoethyl methacrylate).

[0021]Said solvent is acetonitrile, acetonitrile/toluene, acetonitrile/tetrahydrofuran, acetonitrile/methanol, acetonitrile/ethanol, acetonitrile/propanol, acetonitrile/butanol, acetonitrile/pentanol, methanol, ethanol, propanol, butanol, pentanol, water, methanol/water, ethanol/water, propanol/water, butanol/water, pentanol/water, 2-butanone, or liquid paraffin.

[0022]Said template molecule is propranolol, vasolan, pentamidine, theophylline, caffeine, morphine, atenolol, paracetamol, ibuprofen, naproxen, sameridinum, pentamidine, verapamil, tramadol, dopamine, methylsameridinum, amobarbital, alfuzosin, zidovudine, stavudine, bupivacaine, mepivacaine, ropivacaine, neurosedyn, lamotrigine, monosulfuron, nicotine, taxol, vitamin B, vitamin B2, ephedrine, phenylalanine aniline, phenytoin, diazepam, clenbuterol, bromoclenbuterol, bisphenol A, p-tert-butylphenol, p-nitrophenol, parachlorophenol, benzopyrene, diphenyl phosphate, metsulfuron methyl, monosulfuron, clenbuterol, 9-ethyl adenine, melamine, quercetin, penicillin, erythrocin, oxytetracycline, chloramphenicol, ochratoxin A, tetracycline, norfloxacin, fluoroquinolone, cefalexin, ciprofloxacin, enrofloxacin, ofloxacin, cefathiamidine, amoxicillin, carbamazepine, oxcarbazepine, trimethoprim, monothiophosphate, dithiophosphate, pyrophosphate, phosphamide, thiophosphoryl amide, N-methycarbamate pesticide, dimethylamino carbamate, triazine, amidine, nereistoxin insecticides, ureas, dithiocarbamate, sulfamic acids, glucosinolates sulfonic acid esters, trichloromethylthio, pirimicarb, imidacloprid, atrazine, ametryn, alachlor, acetochlor, butachlor, metolachlor, prometryn, paraquat, quizalofop-p-ethyl, imazethapyr, fomesafen, clomazone, benazolin, amitraz, diazinon, acephate, deltamethrin, isoproturon, fenuron, linuron, metoxuron, chlortoluron, metobromuron, tebuconazole, 2-methyl-4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxy acetic acid, simazine, propazine, terbuthylazine, estradiol, ethinyl estradiol, 17-β-estradiol, testosterone, testosterone glucoside acid, cortisone acetate, dexamethasone acetate, dermhealth cream, enfu cream, compound ketoconazole cream, compound ketone cream, triamcinolone cream, halcinonide solution, ketoconazole, eloson, hydrocortisone butyrate, sicorten, sicorten plus, clobetasol propionate, sokhan, iprobenfos, dexamethasone sodium phosphate, cortisone, hydrocortisone, hydrocortisone acetate, hydrocortisone butyrate, dexamethasone, dexamethasone acetate, prednisone, double beclomethasone propionate, mometasone furoate, fluocinolone acetonide, betamethasone dipropionate, halometasone monohydrate, beclomethasone, betamethasone 21-acetate, prednisolone, tobradex, fluorometholone, triamcinolone, halcinonide, or clobetasol propionate.

[0023]In the first aspect, the present invention relates to MIP nanoparticles with surface-grafted hydrophilic polymer brushes, wherein said MIP nanoparticles have a crosslinking degree exceeding 50% and a particle diameter of 10˜500 nm, preferably 10˜300 nm, and more preferably 10˜250 nm, said MIP nanoparticles are capable of recognizing template molecules in biological samples, and in particular pure biological samples, and said MIP nanoparticles are obtained by the hydrophilic macromolecular chain transfer agent and optional small chain transfer agent-mediated RAFT precipitation polymerization of the monovinyl functional monomer and cross-linker in the presence of the template.

[0024]In the second aspect, the present invention relates to MIP nanoparticles with surface-grafted hydrophilic polymer brushes, wherein said MIP nanoparticles have a core formed by the cross-linked polymer networks and hydrophilic polymer brushes grafted onto the core, said core has a crosslinking degree exceeding 50% and a particle diameter of 10˜500 nm, preferably 10˜300 nm, and more preferably 10˜250 nm, the core of said MIP nanoparticles has molecularly imprinted cavities capable of recognizing template molecules in biological samples, and in particular pure biological samples.

[0025]In one preferred embodiment according to the present invention, said nanoparticles have narrow particle size distribution. The particle size distribution indices determined by dynamic laser scattering according to ISO 13321 are preferably less than or equal to 0.6, preferably less than or equal to 0.5, preferably less than or equal to 0.4, preferably less than or equal to 0.3, preferably less than or equal to 0.2, and preferably less than or equal to 0.1.

[0026]In another preferred embodiment according to the present invention, said RAFT precipitation polymerization for the preparation of MIP nanoparticles is induced by the combined use of a hydrophilic macromolecular chain transfer agent and a small chain transfer agent.

[0027]In another preferred embodiment according to the present invention, said template molecule is selected from amino acid, biological receptor, nucleic acid, steroid, immunosuppressant, hormone, heparin, antibiotics, vitamin, small pathological and disease biomarker, toxin, pesticide, herbicide, explosive, neurotoxin, endocrine disrupter, nucleotide, nucleoside, oligomeric nucleotide, metabolin, secondary metabolite, drug metabolite, drug, drug intermediate, or pharmic organic molecule. Particularly, said template molecule is selected from propranolol, vasolan, pentamidine, theophylline, caffeine, morphine, atenolol, paracetamol, ibuprofen, naproxen, sameridinum, pentamidine, verapamil, tramadol, dopamine, methylsameridinum, amobarbital, alfuzosin, zidovudine, stavudine, bupivacaine, mepivacaine, ropivacaine, neurosedyn, lamotrigine, monosulfuron, nicotine, taxol, vitamin B, vitamin B2, ephedrine, phenylalanine aniline, phenytoin, diazepam, clenbuterol, bromoclenbuterol, bisphenol A, p-tert-butylphenol, p-nitrophenol, parachlorophenol, benzopyrene, diphenyl phosphate, metsulfuron methyl, monosulfuron, clenbuterol, 9-ethyl adenine, melamine, quercetin, penicillin, erythrocin, tetracycline, oxytetracycline, chloramphenicol, ochratoxin A, norfloxacin, fluoroquinolone, cefalexin, ciprofloxacin, enrofloxacin, ofloxacin, cefathiamidine, amoxicillin, carbamazepine, oxcarbazepine, trimethoprim, monothiophosphate, dithiophosphate, pyrophosphate, phosphamide, thiophosphoryl amide, N-methycarbamate pesticide, dimethylamino carbamate, triazine, amidine, nereistoxin insecticides, ureas, dithiocarbamate, sulfamic acid class, glucosinolates sulfonic acid esters, trichloromethylthio, pirimicarb, imidacloprid, atrazine, ametryn, alachlor, acetochlor, butachlor, metolachlor, prometryn, paraquat, quizalofop-p-ethyl, imazethapyr, fomesafen, clomazone, benazolin, amitraz, diazinon, acephate, deltamethrin, isoproturon, fenuron, linuron, metoxuron, chlortoluron, metobromuron, tebuconazole, 2-methyl-4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxy acetic acid, simazine, propazine, terbuthylazine, estradiol, ethinyl estradiol, 17-β-estradiol, testosterone, testosterone glucoside acid, cortisone acetate, dexamethasone acetate, dermhealth cream, enfu cream, compound ketoconazole cream, compound ketone cream, triamcinolone cream, halcinonide solution, ketoconazole, eloson, hydrocortisone butyrate, sicorten, sicorten plus, clobetasol propionate, sokhan, iprobenfos, dexamethasone sodium phosphate, cortisone, hydrocortisone hydrocortisone acetate, hydrocortisone butyrate, dexamethasone, dexamethasone acetate, prednisone, double beclomethasone propionate, mometasone furoate, fluocinolone acetonide, betamethasone dipropionate, halometasone monohydrate, beclomethasone, betamethasone 21-acetate, prednisolone, tobradex, fluorometholone, triamcinolone, halcinonide or clobetasol propionate, preferably propranolol, theophylline, caffeine, bisphenol A, penicillin, erythrocin, tetracycline, norfloxacin, amitraz, diazinon, acephate, bromine cyanate este, 2,4-dichlorophenoxyacetic acid (2,4-D), estradiol or testosterone, and more preferably propranolol or 2,4-dichlorophenoxyacetic acid (2,4-D).

[0028]In another preferred embodiment according to the present invention, said monovinyl functional monomer is selected from C2-C8 monoolefin, aromatic vinyl compounds, heterocyclic aromatic vinyl compounds, monoolefin type unsaturated carboxylic acid, carboxylate, ester and amide, vinyl alcohol and its ester, allyl alcohol and its ester, vinyl ether, vinyl lactam, vinyl halide, 1,1-dihaloethylene, (meth)acrylic acid and its ester, salt, and amide, vinylpyridine compound and their combinations, preferably 4-vinylpyridine, 2-vinylpyridine, 4-vinylbenzoic acid, (meth)acrylic acid, trifluoromethylacrylic acid, 2-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, (meth)acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 4-vinylimidazole, itaconic acid or N-vinylpyrrolidone or their mixture, and more preferably 4-vinylpyridine or methacrylic acid.

[0029]In another preferred embodiment according to the present invention, said crosslinker is a monomer with two or more nonconjugated unsaturated double bond, preferably diol or polyol acrylate, methacrylate, allyl ether, or vinyl ether; the esters obtained from unsaturated monohydric alcohol and vinyl-containing C3-C6 carboxylic acid; the esters obtained from unsaturated carboxylic acid and polyol; linear or branched or cyclic aliphatic or aromatic alkanes with at least two double bond, and said double bond is nonconjugated in case of aliphatic alkane; diamine or polyamine acrylamide, methacrylamide, and N-allyl amine; and their combinations, more preferably ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, divinylbenzene, N,N′-methylenebisacrylamide, N,N′-ethylenebisacrylamide, N,N′-phenylbisacrylamide or 1,4-diacryloylpiperazine or their mixture, and more preferably ethylene glycol dimethacrylate.

[0030]In another preferred embodiment according to the present invention, said hydrophilic macromolecular chain transfer agent is selected from hydrophilic polymers with a terminal dithioester or trithiocarbonate group, said hydrophilic macromolecular chain transfer agent is preferably polyalcohol, polylactam, polyurethane, poly(meth)acrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl ether, polyester, polyvinylamine, polyethyleneimine, polyalkylene oxide, poly(carboxylic acid), polyamide, polyanhydride, polyphosphazenes, cellulose, heparin, dextran, polypeptide, fiber protein and elastin, polysaccharide, hyaluronic acid, alginate, gelatin and chitosan gel, albumin, oligopeptides, short chain peptide and oligonucleotides as well as the copolymers synthesized by the monomers of the above polymers, more preferably polyethylene glycol, poly(N-isopropylacrylamide), poly(2-hydroxyethyl methacrylate), polymethacrylamide, poly(N,N-dimethylacrylamide), poly[2-(N,N-dimethyl amino)ethyl methacrylate], poly(N,N-dimethyl aminoethyl methacrylate), poly[[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide], poly[N,N-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl)ammonium], poly(2-methacryloyloxyethyl phosphorylcholine), poly[oxygen(11(3-sulfonylpropyltrimethyl-glycidyl)undecyloxy thiolmethyl)ethylene-co-oxygen(1-dodecanethiolmethyl)ethylene], poly(acrylamide-2-methylpropanesulfonic acid), poly(methacryloxyethyl sulfobetaine), poly[[2-(methacryloyloxy)ethyl]trimethyl ammonium chloride], poly(3-sulfopropyl methacrylate potassium salt), poly[4-(dimethyl(2′-methacryloyloxyethyl)amine)butyrate], poly(methacryloxymethyl sulfobetaine), poly(methacrylamide sulfobetaine), poly(styrene sulfonate), poly(styrene sulfonic acid), poly(acrylic acid), poly(methylacrylic acid), sodium polymethacrylate, poly[methoxy tri(ethylene glycol)methacrylate-co-methacrylic acid], polyethylene glycol, poly[methoxy(ethylene glycol)methacrylate], polyalkylene oxide, polyoxyethylene, poly[methoxyoligo(ethylene glycol)methacrylate], poly(hydroxyethyl methacrylate), poly(N-methylglycine), poly(L-glutamic acid), poly(L-lysine), poly(N-isopropyl methacrylamide), poly(N-hydroxymethyl acrylamide), poly[N-(2,2-dimethyl-1,3-dioxolane-methyl)acrylamide], poly[N-(2-hydroxypropyl)methacrylamide], poly(2-hydroxyethyl acrylate), poly(2,3-dihydroxypropyl methacrylate), poly(ether amine), poly(N-vinylpyrrolidone), poly(N-vinylcaprolactam), poly(-oxazoline) and its derivatives, poly[(2-(diethylamino)ethyl acrylate], poly[(2-(dimethylamino)ethyl methylacrylate], poly[(2-(diethylamino)ethyl methylacrylate], poly(-vinylpyridine), poly(l-vinylimidazole), poly(N-acryloylmorpholine), poly(ethylene glycol ethyl phosphate), and copolymers obtained from the monomers of the above polymers.

[0031]In another preferred embodiment according to the present invention, said small chain transfer agent has the following structure:

[0032]

wherein R=alkyl, alkenyl (alkynyl), aryl, aralkyl, substituted alkyl, substituted aryl, carbocyclic or heterocyclic, alkyloxy or dialkylamine;

[0033]Z=alkyl, aryl, aralkyl, substituted alkyl, substituted aryl, carbocyclic or heterocyclic, alkylthiol, arylthiol, alkoxycarbonyl, aralkoxycarbonyl, acyloxy, carbamoyl, cyano, N-alkyl, N-aryl-substituted amino, alkoxy, aryloxy, dialkyl or diaryl phosphate, dialkyl or diaryl phosphinic,

[0034]said small chain transfer agent is selected from dithioester or trithiocarbonate organic compounds and thiocarbonylthio compounds, for example: 1-pyrrole carbothioic acid 2-cyano-2-propyl ester, 1-pyrrole carbothioic acid 2-cyano-2-butyl ester, 1-imidazole carbothioic acid benzyl ester, cumyl dithiobenzoate, cyanoisopropyl dithiobenzoate, 1-carboxyl isobutyl dithiobenzoate, S-1-dodecyl-S′-(α,α″-dimethyl-α″-acetic acid)trithiocarbonate, dodecyl-S″-isopropanoic acid-trithiocarbonate, xanthate derivatives such as O-ethyl S-(1-phenylethyl)dithiocarbonate, O-ethyl S-(2-ethyloxycarbonyl-2-propyl)dithiocarbonate, and O-ethyl S-(2-cyanoisopropyl)dithiocarbonate.

[0035]In another preferred embodiment according to the present invention, the molar ratio of the template, monovinyl functional monomer, and crosslinker is 1:1˜10:4˜80, preferably 1:1˜9:4˜70, more preferably 1:1˜8:4˜50, more preferably 1:1˜6:4˜10, and more preferably 1:1˜4:4˜10.

[0036]In another preferred embodiment according to the present invention, the molar ratio of the total amount of the monovinyl functional monomer and crosslinker to that of the chain transfer agent (including optional small chain transfer agent and hydrophilic macromolecular chain transfer agent) is 500:1˜10:1, preferably 200:1˜10:1, preferably 150:1˜50:1, and more preferably 150:1˜80:1.

[0037]In another preferred embodiment according to the present invention, the molar percentage of the small chain transfer agent in the total amount of all chain transfer agents including both small chain transfer agent and hydrophilic macromolecular chain transfer agent is 0˜95%, preferably 1˜85%, more preferably 10˜75%, more preferably 15˜70%, and more preferably 20˜60%.

[0038]In another preferred embodiment according to the present invention, said hydrophilic polymer brushes are formed by the macromolecular chain transfer agent.

[0039]In another preferred embodiment according to the present invention, the number-average molecular weights of said hydrophilic macromolecular chain transfer agent range from 500 to 50000, preferably from 1000 to 30000, more preferably from 1500 to 8000, and more preferably from 2000 to 5000.

[0040]In the third aspect, the present invention relates to a method for preparing the MIP nanoparticles with surface-grafted hydrophilic polymer brushes according to the present invention, which includes the following steps:[0041]1) homogeneously mixing template, monovinyl functional monomer, crosslinker, solvent, free radical initiator, hydrophilic macromolecular chain transfer agent, and optional small chain transfer agent, degassing to remove oxygen and carrying out polymerization at a temperature of 25˜100° C., preferably 30˜90° C., more preferably 40˜80° C., and more preferably 50˜70° C., for a period of 1˜500 h, preferably 2˜200 h, and more preferably 3˜100 h, to produce the polymer nanoparticles with entrapped template molecules; and[0042]2) washing the resulting polymer nanoparticles with entrapped template molecules with an appropriate solvent until no template molecules can be detected in the washing solution, so as to obtain the MIP nanoparticles with surface-grafted hydrophilic polymer brushes.

[0043]In the fourth aspect, the present invention relates to a method for preparing the MIP nanoparticles with surface-grafted hydrophilic polymer brushes according to the present invention, which includes the following steps:[0044]1) homogeneously mixing template, monovinyl functional monomer, crosslinker, solvent, free radical initiator, hydrophilic macromolecular chain transfer agent, and optional small chain transfer agent, purging with argon or nitrogen for 5˜60 min to remove oxygen, polymerizing in an oil bath with a temperature of 25˜100° C. for 1˜100 h, dispersing with ultrasonic for 5˜30 min, and centrifugating with high speed to obtain polymer nanoparticles with entrapped template molecules; and[0045]2) washing the resulting polymer nanoparticles with entrapped template molecules with methanol/acetic acid (with a volume ratio of 10/0.1˜10/10) for 12˜72 h and methanol for 12˜48 h successively until no template molecules can be detected in the washing solution, and drying at 20˜60° C. under vacuum to the constant weight, so as to obtain MIP nanoparticles with surface-grafted hydrophilic polymer brushes.

[0046]In one preferred embodiment according to the preparation method of the present invention, a series of MIP nanoparticles with surface-grafted hydrophilic polymer brushes and molecular recognition ability toward different template molecules can be prepared by changing the types and used amounts of the functional monomer, crosslinker, initiator, small chain transfer agent, macromolecular chain transfer agent, template, and solvent.

[0047]In another preferred embodiment according to the preparation method of the present invention, said initiator is azo type free radical initiator, peroxide type free radical initiator, or redox type initiator, said azo type free radical initiator is preferably selected from 2,2′-azobisisobutyronitrile, 2,2′-azobisisoheptonitrile, 2,2′-azobis(2-cyano-2-butane), 2,2′-azobis (methyl isobutyrate), 4,4′-azobis(4-cyanovaleric acid), 4,4′-azobis(4-cyano-1-pentanol), 1,1′-azobis(cyanocyclohexane), 2-tert-butylazo-2-cyanopropane, 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2′-azobis[(2-methyl-N-hydroxyethyl)propionamide], bihydrochloride 2,2′-azobis(N,N′-bimethylene isobutyl amy), bihydrochloride 2,2′-azobis(2-amidinopropane), 2,2′-azobis(N,N′-bimethylene isobutylamine), 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide}, 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], dihydrate 2,2′-azobis(isobutyramide), 2,2′-azobis(2,2,4-trimethylpentane), 2,2′-azobis(2-methylpropane); said peroxide type free radical initiator is preferably selected from tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneodecanoate, tert-butyl perisobutyrate, tert-amyl perpivalate, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, dicumyl peroxide, benzoyl peroxide, dilauroyl peroxide, potassium persulfate, ammonium persulfate, di-tert-butyl hyponitrite, di-t-butyl peroxide or p-dipropylbenzene hyponitrite, cumyl hydroperoxide, tert-butyl hydroperoxide; for said redox type free radical initiator, wherein the oxidants include organic (alkyl-, aryl-, acyl-)hydrogen peroxide, persulfate, superphosphate, organic peroxide, preferred oxidants include persulfate and organic hydrogen peroxide, and the most preferred oxidants include ammonium, sodium, or potassium persulfate, tert-butyl hydroperoxide, reducing agents include sodium formaldehyde sulfoxylate, sodium sulfite, sodium metabisulfite, sodium dithionite, ascorbic acid, D-isoascorbic acid, hydrazine, hydroxylamine or its salt, reducing sugar, mercaptan, and sulfonic acid derivatives, aluminumtriethyl, triethylborane, tertiary amine, preferred reducing agents include sodium formaldehyde sulfoxylate, sodium metabisulfite, D-isoascorbic acid, sodium hydrosulfite, sodium thiosulfate, sodium sulfite, and the most preferred reducing agent is sodium dithionite.

[0048]In another preferred embodiment according to the preparation method of the present invention, the polymerization solvent is acetonitrile, acetonitrile/toluene, acetonitrile/tetrahydrofuran, acetonitrile/methanol, acetonitrile/ethanol, acetonitrile/propanol, acetonitrile/butanol, acetonitrile/pentanol, methanol, ethanol, propanol, butanol, pentanol, water, methanol/water, ethanol/water, propanol/water, butanol/water, pentanol/water, toluene, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, 2-butanone or liquid