Enhanced wear resistance,antibacterial performance,and biocompatibility using nanotubes containing nano-Ag and bioceramics in vitro

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 TiO_(2)nanotubes(diameter:(80±20)nm and(150±40)nm)using anodization,deposition,and spin-coating methods.The effects of the bioceramics(nano-β-tricalcium phosphate,microhydroxyapatite(micro-HA),and meso-CaSiO_(3))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)×10^(−3)mm^(3)/(N·m)due to adhesive and abrasivewear.Meso-CaSiO_(3)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.

Enhanced corrosion resistance,antibacterial properties and osteogenesis by Cu ion optimized MgAl-layered double hydroxide on Mg alloy

Magnesium(Mg)and its alloys have similar densities and elastic moduli to natural bone,making them an excellent choice for orthopedic implants.However,Mg alloys are prone to electrochemical corrosion,which often leads to implant failure and hinders the further development of Mg alloys due to bacterial infection around the implant.This work aims to enhance the corrosion resistance of Mg alloys,and provide theoretical guidance for solving the problem that Mg-based orthopedic implants are susceptible to bacterial infection and,thus,implant failure.In order to solve the corrosion problem,the Mg alloy AZ91D was used as the substrate,and a compact and uniform MgAlCu-layered double hydroxide(Mg(Cu)-LDH)was prepared on its surface using a hydrothermal method.The Mg(Cu)-LDH provides a barrier between the AZ91D and corrosive liquid,which effectively protects the Mg substrate from being corroded.The Mg(Cu)-LDH shows great cell viability for MC3T3-E1 cells.The Cu2+and Mg2+in the coating also endow the Mg(Cu)-LDH/AZ91D with antibacterial properties,showing strong antibacterial effects on both E.coli and S.aureus with antibacterial rates over 85%.Finally,in vivo results indicated that a LDH-coated implant had no systemic effects on the hearts,livers,spleens,lungs or kidneys.It was shown that 4 weeks after surgery the ratio of bone volume to tissue volume(BV/TV)of the LDH implant was 24%,which was 1.7 times that observed for AZ91D.