The Study Of Protein Interaction With Different Model Interfaces

The effect of the interface properties of biomedical materials on protein adsorption behavior is a core problem that to understand the biological compatibility mechanism.In this thesis,model interfaces with different kinds of properties were prepared.Protein adsorption behaviors at these interfaces were studied.Firstly,four kinds of polymer brushes(Poly(2-methacryloyloxyethyl phosphorylcholine(PMPC),Poly(N,N-isopropylacrylamide)(PNIPAM),Poly(tert-Butylacrylate)(PtBA),and Poly(dimethylaminoethyl methacrylate)(PDMAEMA)were synthesized via surface-initiated atom transfer radical polymerization(SI-ATRP).Secondly,the adsorption behaviours of BSA and Fg at these interfaces were studied by surface plasmon resonance(SPR).The influence of the interface thickness and temperature on the protein adsorption were measured.The results show that protein adsorption amount at PMPC brush interfaces was decreased with the increase of its thickness.The PNIPAM polymer interfaces possess excellent effect of protein resistant due to its high water content at room temperature.It was found that it's not water contact angle but the water content of the polymer interface,which correlates with its protein adsorption amount.Four thiol-terminated polymers,Poly(2-methacryloyloxyethyl phosphorylcholine(PMPC-SH),Polyethylene glycol(PEG-SH),Poly(2,2,3,4,4,4-Hexafluorobutyl methacrylate)(PHFBMA-SH)and Poly(2-hydroxyethyl methacrylate)(PHEMA-SH)were synthesized.Firstly,the polymers were grafted on gold surfaces of SPR senor chips through the method of "grafting to" to fabricate the interfaces with different surface energy.The protein adsorption onto the brush layers was monitored by in situ SPR techniques to explore the effects of surface energy and water content on protein adsorption behavior.The effect of protein resistant of four polymer brush interface is not consistent for protein BSA and Fg due to the combined effects of surface energy and water content of the polymer brushes.The kinetic studies showed that BSA and Fg adsorption behaviors accord with Langmuir equation and pseudo-second order equation,respectively.A series of random copolymers poly(methacrylic acid-co-2-methacryloyloxyethyl phosphorylcholine)P(MAA-co-MPC)were synthesized firstly via RAFT living polymerization.The P(MAA-co-MPC)copolymer side chains bear cell membrane phosphorylcholine zwitterions to endow biocompatibility and carboxylic groups to confer coordination with metal ions.Thus,the copolymer was adopted to modify Fe3O4 nanoparticle by a one-pot coprecipitation approach.The effects of the copolymer composition as well as the ratio between the copolymers and iron ions on the performances of the magnetite nanoparticles were researched.The diameters of the nanoparticles could be easily tuned by changing the initial copolymer amount.Moreover,a long-term colloidal stability of magnetite particles was obtained after P(MAA-co-MPC)modification.Biocompatibility of the P(MAA-co-MPC)copolymer coated magnetite nanoparticles was investigated by protein adsorption,in vitro cytotoxicity and cell uptake studies.It was found that the copolymer content of magnetite nanoparticles correlates with its biocompatibility.Excellent biocompatibility could be obtained when the content of the copolymer in the composite nanoparticles reached to 54%.