Preparation And Properties Of P(AA-co-MPC) Modified Superparamagnetic Nanoparticles

In order to improve the dispersion and colloidal stability of superparamagnetic Fe₃O₄nanoparticles,as well as broaden their applications in biomedical fields,copolymers(P(AA-co-MPC))with different monomer molar ratio of acrylic acid(AA)and 2-methacryloyloxyethyl phosphorylcholine(MPC)were synthesized via RAFT polymerization and the superparamagnetic Fe₃O₄nanoparticles were modified by these synthesized copolymers(P(AA-co-MPC))through coprecipitation method.The chemical structures,molecular weight and molecular weight distributions,and thermal properties of the copolymers were characterized by ¹H NMR,FTIR,GPC and TG.Meanwhile,the hydrodynamic particle size and particle size distribution,surface properties and morphologies,chemical structures,thermal stability,crystal structures and the magnetic properties of the magnetic nanoparticles were analyzed by Zeta potential and particle size analyzer,TEM,FTIR,TG,XRD and Squid-VSM magnetic measure system.The biocompatibility of the modified superparamagnetic nanoparticles was evaluated by protein adsorption test,in vitro cytotoxicity study,in vitro cellular uptake study and blood circulation time test.The results show that P(AA-co-MPC)with different monomer mole ratio and narrow molecular weight distribution(about 1.21?1.4)are synthesized by RAFT polymerization.The surface of the magnetic Fe₃O₄nanoparticles is modified by these synthesized copolymers(P(AA-co-MPC)).Compared with unmodified superparamagnetic Fe₃O₄nanoparticles,modified nanoparticles possess smaller hydrodynamic particle size and narrower particle size distribution,higher Zeta potential and remarkably improvement in dispersion and colloidal stability.The nanoparticles modified by the P(AA-co-MPC)with molar ratio of AA:MPC of 1:1 exhibit the smallest particle size(36.54±4.00nm),the narrowest particle size distribution and the highest Zeta potential(-30.98±1.25m V).The saturation magnetization is 65.57emu/g.Meanwhile,the cellular uptake of these superparamagnetism nanoparticles show the least cellular uptake,long blood circulation time about 96 hours,long in vivo residence time and strong anti-protein adsorption ability.The absorption amount of AVD protein,BSA protein and plasma is only 0.023,0.014 and 0.021mg/mg,respectively.These magnetic Fe₃O₄nanoparticles with low cellular toxicity have a promoting effect on cell proliferation.Thus,they are ideal biomedical materiels.