Use of Chitosan as a Bioactive Implant Coating for Bone-Implant Applications

Chitosan is the deacetylated derivative of the natural polysaccharide, chitin. Chitosan has been shown to be biocompatible, biodegradable, osteoconductive, and to accelerate wound healing. These characteristics are largely due to its structural and chemical homology to hyaluronic acid and other proteoglycans found in extracellular matrices. Because of these properties, chitosan has been investigated as a coating for implant materials to promote osseointegration, and as a potential vehicle to deliver therapeutic agents to the local implant-tissue interface. The coating of chitosan onto implant alloy surfaces has been achieved via chemical reactions and electrodeposition mechanisms as well as by other methods such as dip coating and layer-by-layer assembly. This work examines the different mechanisms and bond strengths of chitosan coatings for implant alloys, coating composition and physiochemical properties, degradation, delivery of therapeutic agents, such as growth factors and antibiotics, and in vitro and in vivo compatibilities. © 2011 Springer-Verlag Berlin Heidelberg