Study On The Recognition Property Of Biomacromolecules By Magnetic Ionic Liquid Molecularly Imprinted Polymers

Molecular imprinted technology?MIT?is an effective and promising technique to facilitate tailor-made binding sites for the target molecules.Molecularly imprinted polymers?MIPs?are subsequently created by the polymerization or polycondensation of a mixture of appropriate functional monomers and cross-linkers in the presence of molecules?called template?.After removal of the template molecules,it leaves complementary three-dimensional recognition cavities which are capable of selectively rebinding the target molecules.Because of the existence of binding sites,MIPs have a strong selective recognition ability for template molecules,which is similar to the relationship between key and lock.Compared to natural receptors?i.e.enzymes,nucleic acids,antibodies,active proteins,etc?,MIPs possess unique feature s.To date,the molecular imprinting technology against low-molecular weight molecules is well developed.The successful imprinting of biomacromolecules?i.e.,protein,microorganism,virus and DNA?still remains a great challenge because of the difficult template removal,poor site accessibility,conformational flexibility and large size.Therefore,we need to explore new ways to solve the above problems.Ionic liquids?ILs?are the low temperature-melting organic salts,which consist of bulky organic cations and organic or inorganic anions.ILs have aroused increasing attention in the different fields of chemistry owing to their unique properties,including high chemical stability,negligible vapour pressure,non-flammability,high ionic conductivity.Particularly,imidazolium ILs have been used not only as solvents and stabilizers but also as organic surface modifiers and functional monomers in the preparation of MIPs.In this study,three types of novel magnetic surface molecularly imprinted polymers were prepared by combining molecular imprinting technique with ionic liquids,and their adsorption properties were systematically studied.The main contents are as follows:?1?Adsorption and specific recognition of DNA by using imprinted polymer layers grafted onto ionic liquid functionalized magnetic microspheresImidazolium ionic liquids were introduced on the surface of silica-coated Fe₃O₄microsphere?Fe₃O₄@SiO₂@IL?.Then the imprinted polymer layers were grafted onto ionic liquid functionalized microspheres through sol-gel approach using N-3-?3-triethoxysilylpropyl?-3-aminopropyl imidazolium chloride?[TESPAPMIM]Cl?and N-3-?3-triethoxysilylpropyl?-3-mexyl imidazolium chloride([TESPMIM]Cl as the functional monomers,tetraethoxysilane?TEOS?as the cross-linker and DNA from salmontestesasthe template.The molecularlyimprintedmicrospheres?Fe₃O₄@SiO₂@IL-MIPs?were synthesized.Because both imidazolium ionic liquid and DNA are soluble in water,it is mandatory to implement an imprinted process in an aqueous medium to well maintain the integrity of the conformation.Fourier transform infrared spectrometry,thermogravimetric anaLyzis,transmission electron microscopy,X-ray diffraction and vibrating sample magnetometry were employed to characteri ze the materials.The adsorption capacity of prepared DNA-imprinted microspheres for DNA can attain to 162.4 mg·g^-1.The DNA-imprinted nanomaterials exhibited a satisfactory selective adsorption toward DNA?the impriting factor is 6.65?over other non-imprinted macromolecules at pH value of 5.10,and also shown rapid separation,favorable reusability and fast elution character.Moreover,the imprinted microspheres can separate and adsorb DNA efficiently from calf whole blood,which provided a new idea for specifically capturing DNA in a complex matrix.?2?Preparation of magnetic ionic liquid-molecularly imprinted polymers for the specific recognition and separation of LysozymeAfacilecore-shellionicliquid-molecularlyimprintedpolymers?Fe₃O₄@VTEO@IL-MIPs?was synthesized for the specific extraction of Lysozyme?Lyz?.TheFe₃O₄@VTEO@IL-MIPswerepreparedbyusingdouble bond-functionalizedFe₃O₄nanoparticles?Fe₃O₄@VTEO?ascarrierand1-??-allylacetate?-3-N-?3-aminopropyl?-imidazolium chloride?[AAPIM]Cl?as function monomer.Fe₃O₄ nanoparticles were protected by polymers,which can prevent Fe₃O₄ nanoparticles oxidized and conglomerated.[AAPIM]Cl,the functional monomer of the MIPs,can forme strong interactions with template and remarkably improved the imprinting effect.The transmission electron microscope?TEM?,thermogravimetric anaLyzis?TGA?,X-ray diffraction?XRD?,vibrating sample magnetometer?VSM?and fourier transform infrared spectrometry?FT-IR?.were used to characterize the composition and morphology of the prepared MIPs.The secondary structure of the protein was evaluated by the circular dichroism?CD?spectra.The adsorption capacity of the MIPs for Lyz can attain 213.7 mg·g^-1 and the impriting factor is 2.02.In addition,2.5 h was chosen as the suitable adsorption time.From the reusability experiments,it can be seen that the magnetic MIPs microspheres can be used four times at least.Furthermore,Fe₃O₄@IL-MIPs can separate Lyz from chicken egg white real sample successfully.?3?Preparation of magnetically imprinted polymers based on unsaturated double bond functionalized imidazole ionic liquids as cross-linkers for the recognition and separation of LysozymeWith the double bond-functionalized Fe₃O₄ nanoparticles?Fe₃O₄@VTEO?as carrier,acrylamide?AAm?asfunctionmonomerand1-??-acetyl allyl?-3-vinylimidazole chloride?[AVIM]Cl?as cross-linker,a core-shell imprinted microsphere?IL-Fe₃O₄@VTEO@AAm-MIPs?was prepared by surface imprinting to selectively adsorb Lysozyme.The thermogravimetric anaLyzis,Fourier transform infrared spectrometry,transmission electron microscopy,X-ray diffraction and vibrating sample magnetometry were employed to characterize the materials.It has been demonstrated that ionic liquid molecule-imprinted polymer is synthesized.The adsorption capacity of the MIPs for Lyz can attain 334.08 mg·g^-1 and the impriting factor is 2.93.In addition,10 h was chosen as the suitable adsorption time.The MIPs also shown rapid separation,favorable reusability and fast elution character.From the reusability experiments,it can be seen that the magnetic MIPs microspheres can be used four times at least.Furthermore,IL-Fe₃O₄@VTEO@AAm-MIPs can separate Lyz from chicken egg white real sample successfully.