Effect of molecular weight on the oleoyl-chitosan nanoparticles as carriers for doxorubicin

Self-assembled oleoyl-chitosan (OCH) nanoparticles based on chitosan with different molecular weights (5 kDa, 38 kDa and 300 kDa) were prepared by oil/water (O/W) emulsification method. The nanoparticles have spherical shape and the mean diameters were 131.8 nm, 255.3 nm and 334.1 nm, respectively. Doxorubicin hydrochloride (DOX) was efficiently loaded into OCH nanoparticles and shown to be sustained release in PBS. The loading efficiency and the DOX release rate increased as the molecular weight of chitosan decreased. The blank OCH nanoparticles showed no cytotoxicity to mouse embryo fibroblasts and human lung cancer cell line A549. The inhibitory rates of DOX-loaded OCH nanoparticle suspension to A549 cells significantly outperformed that of DOX solution, and decreased with the increase of molecular weight. These results revealed the promising potential of low molecular weight OCH nanoparticles as carriers for antitumor agents.