Biocompatible magnetite nanoparticles synthesized by one-pot reaction with a cell membrane mimetic copolymer

In this paper, 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%.