Osteoconductive Nanocomposite Coating of Apatite-Wollastonite and Chitosan

Here, we show the importance of the marine biomaterial chitin and its derivative, chitosan, in bioimplant applications. Titanium and titanium alloys have shown high potential for load bearing in bioimplant applications. However, after their application, a bond with living bone often does not develop or the integration of the implants with bone tissue takes several months. Moreover, the surface of any material implanted in living body changes over time. Titanium ions may be released from the implant surface, following corrosion and wear. Therefore, the metallic implants coated with bioactive materials are able to induce a biological bonding with both soft and hard tissues. Chitin, an important marine biomaterial, and its derivative, chitosan, is an excellent bioactive material compatible with human biological environment and has good flexural strength and osteoconductive properties. Apatite-wollastonite (AW) has been regarded as a promising biomaterial due to its high biocompatibility, good bioaffinity and osteoconductivity and its crystallographic and chemical similarity with human bone and teeth. However, coating them at ambient temperatures onto titanium implants have proven difficult. We will discuss a new technique that we have developed using electrophoresis to coat a chitosan-AW composite onto a titanium substrate and demonstrated its useful mechanical and biochemical properties and its bioactivity.