Research On The Construction And Performance Optimization Of The Three-dimensional Structure Coating Of The Cell-like Outer Membrane

The development of nonfouling materials and surfaces is critical to many applications,such as biomaterials and biosensors.The prevention of nonspecific protein adsorption on surfaces has been an important challenge to biomaterials scientists.Hydrophilic polymers such as poly(ethylene glycol)(PEG)with perfect flexibility and zwitterionic polymer containing cell membrane phosphorylcholine groups have been widely used to reduce nonspecific protein adsorption.Bioinspired by the universal adhesion of dopamine,biomimetic anti-fouling coating,which could stably bind onto different surfaces of materials,was built and formed a cell outer membrane mimetic stereoscopic structures combining phosphorylcholine with PEG.Furthermore,the targeting molecule,folic acid,was grafted to anti-fouling polymer coating to make the coating more functional.The research mainly include the following aspects:(1)Synthesis and properties of a series of biomemitic copolymer bearing cell outer membrane phosphorylcholine,mussel adhesive protein dopamine and PEG.A series of random copolymers PMENG(poly(MPC-co-NPCEMA-co-PEG A))with different compositions were synthesized by a free radical polymerization,and dopamine was grafted to the active ester groups of PMENG.Both of PMENG and PMEDG copolymers were characterized by 1H-NMR.The PMEDG polymers were coated on different materials and treated by heating or soaked in the water to prepare stereoscopic cell outer membrane mimetic surfaces.The hydrophilicity of the coating was chatacterized by dynamic contact angle(DCA).The element composition and morphology of the coating surface were investigated by X-ray photoelectronic spectroscopy(XPS)and atomic force microscopy(AFM).(2)Fouling resistance performance of the stereoscopic cell outer membrane mimetic surfaces was evaluated.The adsorption amount of BSA and Fg was tested by two different methods,bicinchoninic acid disodium(BCA)and surface plasmon resonance(SPR).The adhered blood platelets on the modified surfaces were observed by scanning electron microscopy(SEM).The mouse fibroblast cell line L929 was used to test cytotoxicity and the number of attached cells was analysed by inversion fluorescence microscope.Compared with bare substrate,PMEDG films significantly suppressed the adsorption of proteins and the adhesion of platelets and L929 cells.PMEDG solutions with different polymer concentrations were almost harmless for the cell survival,even non-toxic in low concentration of polymer solutions.These results demonstrated that cell outer membrane mimetic surface modification with PMEDG could improve the blood compatibility of substrates.(3)The synthesis of polymers with folic acid targeting groups and the construction of functional coating.Biomimetic random copolymers PMEDGF comprising 2-methacryloyloxyethyl phosphorylcholine(MPC),dopamine,polyethylene glycol(PEG)and folic acid were synthesizedand characterized by 1H-NMR.The copolymers were immobilized on polydopamine precoated different substrates.The hydrophilicity and morphology of the coating surface were tested by DCA and AFM.