Multifunctional Iron Oxide Nanoparticles Coated by Novel Biocompatible Zwitterionic Polymer

A novel multifunctional magnetic nanoparticles(MNPs) coated by the biocompatible zwitterionic polymer, poly(carboxybetaine methacrylate)(pCBMA) were prepared by a self-assembling method. The pCBMA coating not only stabilized the MNPs in complex mediums, but also provided abundant functional groups to the MNPs. The prepared pCBMA-MNPs had a hydrodynamic particle size of about 130 nm and a strong saturated magnetization of 110 emu/g Fe, which is 1.6 times higher than that of the commercial product Feridex. In vitro stability studies showed the pCBMA-MNPs could achieve long-term stability in commonly use medium like PBS and also in high ionic strength solution like 10% NaCl solution for at least 6 monthes. Moreover, comparing to the dextran coated MNPs, pCBMA-MNPs presented better stability in 100% human blood serum incubated at 37 C. Macrophage cells uptake studies revealed that the uptake ratio of pCBMA-MNPs was much lower than the dextran-MNPs. Cell targeting studies showed that, after conjugated with targeting ligand, the cell uptake rated was notably increased.