Chitosan-poly(acrylic acid) complex modified paramagnetic Fe₃O₄ nanoparticles for camptothecin loading and release

Abstract

The stable superparamagnetic colloidal suspension of chitosan-poly(acrylic acid) (CS-PAA)/Fe3O4 nanoparticles was synthesized by graft copolymerization AA on the surface of CS stabilized Fe3O4 nanoparticles. The size, size distribution, structure, and magnetic properties of the resultant CS-PAA/Fe3O4 nanoparticles were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), dynamic light scattering, Fourier transform infrared spectroscopy, x-ray diffraction, and vibrating sample magnetometry (VSM). FE-SEM and TEM showed the spherelike morphology of CS-PAA/Fe3O4 nanoparticles with their diameter ranging from 15 to 60 nm. VSM measurements indicated that CS-PAA/Fe3O4 nanoparticles preserved the superparamagnetism. CS-PAA complex was proved to be a good stabilizer to prepare the well-dispersed suspension of superparamagnetic Fe3O4 nanoparticles. The stabilizing mechanisms were attributed to the electrostatic repulsion and steric hindrance. The controlled release of entrapped camptothecin from these magnetic nanoparticles was studied and the release mechanism was analyzed.