A good Ti-based joint implant should prevent stress shielding and achieve good bioactivity and anti-infection performance. To meet these requirements, the low-elastic-modulus alloy-Ti-35Nb-2Ta-3Zr-was used as the subs...
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A good Ti-based joint implant should prevent stress shielding and achieve good bioactivity and anti-infection performance. To meet these requirements, the low-elastic-modulus alloy-Ti-35Nb-2Ta-3Zr-was used as the substrate, and functional coatings that contained bioceramics and Ag ions were prepared for coating on TiO2 nanotubes (diameter: (80 +/- 20) nm and (150 +/- 40) nm) using anodization, deposition, and spin-coating methods. The effects of the bioceramics (nano-beta-tricalcium phosphate, microhydroxyapatite (micro-HA), and meso-CaSiO3) and Ag nanoparticles (size: (50 +/- 20) nm) on the antibacterial activity and the tribocorrosion, corrosion, and early in vitro osteogenic behaviors of the nanotubes were investigated. The tribocorrosion and corrosion results showed that the wear rate and corrosive rate were highly dependent on the features of the nanotube surface. Micro-HA showed great wear resistance with a wear rate of (1.26 +/- 0.06)x10-3 mm3/(N center dot m) due to adhesive and abrasive wear. Meso-CaSiO3 showed enhanced cell adhesion, proliferation, and alkaline phosphatase activity. The coatings that contained nano-Ag exhibited good antibacterial activity with an antibacterial rate of >= 89.5% against Escherichia coli. These findings indicate that hybrid coatings may have the potential to accelerate osteogenesis. [GRAPHICS] .
Prevalence of bacterial species involved in biomineralization of manganese on titanium (Ti) surfaces in marine environment was revealed in this research work. This study involves one year sea water exposure of Ti an...
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Prevalence of bacterial species involved in biomineralization of manganese on titanium (Ti) surfaces in marine environment was revealed in this research work. This study involves one year sea water exposure of Ti and their periodical biofilm characterization was carried out to quantify the manganese oxidizing bacterial (MOB) presence in the biofilm formed on titanium surfaces. The total viable count study of Ti coupons exposed to sea water for one year resulted in 60% of the MOB in overall biofilm population. The biochemical characterization of MOB isolates were performed for the genus level identifcation of the seven bacterial isolates. Further, the seven strains were subjected to 16S rRNA gene sequencing. Evolutionary analysis was performed using MEGA 7 to obtain closely related strains within the groups. The manganese oxidizing ability of the bacterial isolates were determined with Leucoberbelin Blue Assay (LBB) and Atomic Absorption Spectroscopy studies (hAS). The results show that among the isolated marine MOB species, Bacillus sp. and Leptothrix sp. have the maximum Mn oxidizing property. The microtitre plate assay was performed to determine the biofilm forming ability of the isolated marine MOB species. All the results have confirmed the prevalence of Bacillus sp. among the biofilm colonizers on Ti surfaces when exposed in sea water.
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