Synthesis and characterization of a novel MPEG–chitosan diblock copolymer and self-assembly of nanoparticles

In this paper, a simple and novel method based on free-radical polymerization initiated by potassium persulfate (KPS) was developed to synthesize the MPEG–chitosan diblock copolymer (MPEG–CS). The obtained MPEG–CS diblock copolymer was characterized by Fourier transform infrared (FTIR), 1H nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The MPEG–CS copolymer could self-assemble into nanoparticles in aqueous solution. A typical TEM photography indicated that the well-spherical nanoparticles with diameter at about 200 nm were obtained. In vitro cell culture assay indicated that MPEG–CS nanoparticles are non-toxic and cell-compatible as the polymer concentration was smaller than 0.6 mg/ml. In conclusion, the obtained MPEG–CS nanoparticles might have great potential application in drug-delivery system.