Surface phosphorylation of chitosan significantly improves osteoblast cell viability, attachment and proliferation

Chitosan biocompatibility is often associated with the structural similarities with glycosaminoglycans (GAGs). Although all of the GAGs are built from repeating disaccharide units and some of them contain N-glucosamine (the main hexosamine in the chitosan backbone), all of them also contain negatively charged functional groups. These charged units are believed to have a crucial role for the formation of proteoglycans and hence for key biochemical processes/signaling related to cell functionality and survival. Lack of these groups in chitosan structure could be the reason for the previously observed poor cell adhesion to this material. Herein, we report that plasma induced grafting of negatively charged phosphonic groups can induce remarkably distinguishable cell response and significantly improve the adhesion, proliferation and viability of osteoblast cells. The proposed plasma induced polymerization is a very simple and versatile method and can be easily adapted to other materials and different negatively charged units.