Chitosan-membrane interactions and their probable role in chitosan-mediated transfection.

Recent studies in our laboratory have shown that chitosan, a polycationic polymer of glucosamine, can facilitate the transfection of HeLa cells with a plasmid that codes for beta-galactosidase. Although chitosan can bind to DNA and other polyanions, the kinetics of complexation might differ depending on the polyanion tested. This evidence suggests that, in addition to ionic interactions, the carbohydrate backbone of chitosan might have an important role in the process of transfection. Beads prepared by the complexation of chitosan with polyphosphate were used to investigate the nature of cellular interactions with chitosan. HeLa cells bound to chitosan-polyphosphate beads could be readily displaced from the beads with methyl alpha-D-mannopyranoside but not with NaCl. Membrane proteins solubilized by CHAPS bound readily to chitosan-polyphosphate beads. A major fraction of the membrane proteins could be eluted from the beads with methyl alpha-D-mannopyranoside. These results suggest that non-ionic interactions between the carbohydrate backbone of chitosan and cell surface proteins might have an important role in the chitosan-mediated transfection of HeLa cells.