Surface modification of bio-implantable Ti-6Al-4V alloy for enhanced osseointegration and antibacterial capability
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Surface-induced osseointegration and antibacterial capability are very important criteria for the clinical success of titanium implants. To enhance these two criteria, an architectural hybrid system is constructed onto Ti-6Al-4V with a rough surface. First, thermal oxidation (TO), treatment with hydrogen peroxide (H2O2) and a mix of TO and H2O2 (Mixed) are used to modify the surface topography and chemistry of Ti-6Al-4V disks. Surface characterizations by the use of microscopes and spectroscopes indicate that TO can induce more favorable topography, roughness, wettability and hydroxyl group concentration on Ti-6Al-4V surfaces. Therefore, an alginate/chitosan LBL film that incorporates antibacterial nano-silver is bridged onto thermally oxidized Ti-6Al-4V alloy by mussel-inspired dopamine. The microscopies and spectrometers confirm that the hybrid system is successfully fabricated onto the Ti-6Al-4V surface while the sub-micron topography induced by TO is maintained. Bone marrow stem cell (BMSC) adhesion, proliferation and differentiation are up-regulated by the synergy of sub-micron surface produced by TO and alginate/chitosan LBL film. The incorporation of nano-silver into the hybrid system is demonstrated to inhibit the growth of Escherichia coli and Staphylococcus aureus, but not jeopardize the enhanced BMSC activities. Taken together, this thesis presents a promising strategy to fabricate novel Ti-6Al-4V implants with enhanced osseointegration and antibacterial capability.