Engineering three-dimensional structures using bio-inspired dopamine and strontium on titanium for biomedical application

The excellent mechanical properties and chemical stability of titanium and its alloys have led to their wide use as a material for dental and orthopaedic implants. However, the bio-inert nature of these materials must be overcome to enhance cell affinity and cell function following implantation. Effective implants require strong interfacial bonding, mechanical stability, osteoblast attachment, enhanced spreading and growth during early stages, and induced differentiation and mineralization in later stages. This study developed an organic-inorganic multilayer coating process for the modification of titanium implants in order to improve cell responses. A three-dimensional structure comprising strontium and micro-arc oxidized (MAO) titanium was covered with a film of poly(dopamine) to form a multilayer coating. The titanium surface formed a uniform hydrophilic oxide coating, which was firmly adhered to the surface. The poly(dopamine) film facilitated the initial attachment and proliferation of cells. Cell differentiation was enhanced by the release of strontium from the coatings. Our results demonstrate the efficacy of the proposed coating process in enhancing the multi-biological function of implant surfaces.