Synthesis And Adsorption Properties Of Magnetic Lysozyme Surface Imprinted Microspheres

Molecular imprinted technology provides a unique way to specifically identify template molecules and prepare molecular imprinted polymers(MIPs)with specific functions,which are easy to prepare,inexpensive,and stable compared to other recognition materials.Nowadays the molecular imprinted technology for small molecules as template molecules is relatively mature.Comparing with small molecule imprinted technology,the development of molecular imprinted technology using protein as template molecule is slow due to their complex structure,large size,and flexible conformation.Therefore,how to obtain protein-imprinted polymers easily and achieve selective protein adsorption is still a challenge in the field of protein molecular imprinted technology.By using Fe3O4 particles with superparamagnetic properties as a carrier,combining with surface imprinted technology to immobilize template proteins lysozyme(Lyz)on the surface of Fe3O4 particles,the magnetic lysozyme surface imprinted microspheres(Lyz-MIPs)were obtained.The specific recognition of the Lyz-MIPs was improved by adjusting the electrostatic adsorption rate of Lyz on the Fe3O4 microspheres surface,the elution mode of template form Lyz-MIPs,as well as the thickness of the imprinted PDA shell.Finally,the Lyz-MIPs with high adsorption capacity,high separation rate,and excellent recognition performance were prepared.More details of the study are listed as follows.(1)By adjusting the pH of the solution,Lyz was immobilized on the surface of Fe3O4 particles by electrostatic adsorption.Dopamine(DA),which is capable of self-polymerization under weak alkaline conditions,was used as the functional monomer,and Lyz-MIPs were successfully prepared by surface imprinted technology.The recognition ability of the Lyz was improved by adjusting the adsorption rate of the Lyz on the surface of Fe3O4 particles,the elution method of the template and the thickness of the imprinted layer of polydopamine(PDA).The magnetic lysozyme surface imprinted microspheres(Lyz-MIPs)with high adsorption capacity and good recognition ability were prepared,and its adsorption amount was 122 mg·g-1,the imprinted factor(IF)was 2.7,and the adsorption equilibrium time was 120 min.In the selective adsorption and binary protein competition experiments,the Lyz-MIPs showed significant specific recognition of Lyz,which proved its promising application in real samples.(2)Taking the high non-specific adsorption of Lyz on the surface of the prepared imprinted layer into consideration,the selective recognition ability of the Lyz-MIPs can be significantly enhanced by a polymer chain with anti-protein adsorption properties,this allows for more effective target detection.In this chapter,based on the previously prepared Lyz-MIPs,the anti-protein adsorption chain mPEG2000-NH2 was grafted onto the non-imprinted region of Lyz-MIPs using the Schiff base reaction between the benzoquinones of PDA and the amino groups of methoxy polyethylene glycol amine(mPEG-NH2),to reduce the non-specific adsorption of Lyz.After grafting the mPEG-NH2,the adsorption amount was reduced to 85 mg·g-1,the IF value was 5.7 and the adsorption equilibration time was 160 min.The specific adsorption and recycling performance experiments demonstrated that the introduction of the PEG2000 successfully reduced the non-specific adsorption and improved the affinity and specific recognition of the template protein.