Preparation and Properties of Chitosan-graft-Poly( methyl methacrylate) Nanoparticles Using Potassium Diperiodatocuprate (III) as an Initiator

Graft copolymer nanoparticles prepared from chitosan (CS) and methyl methacrylate (MMA) monomer were synthesized in aqueous solution by using potassium diperiodatocuprate [Cu(III)] as an initiator and characterized in terms of particle size, zeta potential, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal stability, and X-ray diffraction spectrometry. The results indicated that CS was covalently linked to poly(methyl methacrylate) (PMMA), and the resulting copolymers formed nanoparticles. These nanoparticles [prepared at 35 degrees C, in a weight ratio of MMA/CS of 5 : 1 and with a Cu(III) concentration of 1.5 x 10(-3) mol/L] were 54-350 nm in size, with a mean hydrodynamic diameter of 183 +/- 3 nm and were highly uniform in particle-size distribution, with a rather spherical shape and an obvious positive charge surface. The effect of reaction conditions such as Cu(III) concentration, reaction temperature, and the weight ratio of MMA/CS on the mean particle size was also investigated. Insulin-loaded nanoparticles were prepared, and their maximal association efficiency was up to 85.41%. The experiment of release in vitro showed that the nanoparticles gave an initial burst release followed by a slowly sustained one. VC 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 2707-2715, 2011