Preliminary study of microstructure, mechanical properties and corrosion resistance of antibacterial Ti-15Zr-xCu alloy for dental application

Abstract

Ti-15Zr-xCu (3 ≤ x ≤ 7, wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties, biological responses and corrosion resistance were designed and fabricated. Annealing heat treatment on Ti-15Zr-7Cu (TZC-7A), after holding for 2 h at slightly above their beta transus temperature (BTT) ensured their tensile strength (UTS), yield strength (YS) and hardness (HRV) were improved by 31.2%, 20% and 12.3% respectively compared to the control without Cu, Ti-15Zr (T-15ZA). Although the 3 wt.% Cu alloy displayed the highest elongation (26%), the TZC-7A alloy also possessed a good ductility. Presence of evenly dispersed Ti2Cu and Zr2Cu Cu-rich intermetallic phases formed as interwoven and alternating lamellae within the α + β matrix as a result of Cu addition, as revealed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These greatly contributed to their strengthening and bactericidal properties. Over 98% antibacterial effect against E. coli and S. aureus have been imparted, coupled with excellent biofilm inhibition. Potentiodynamic polarization curves showed that the TZC-7A alloy possessed higher corrosion resistance than commercially pure titanium, cp-Ti; contact angle test revealed enhanced hydrophilicity; while confocal laser scanning microscopy (CLSM) and cell counting kit (CCK-8) assays also displayed drastically lowered bacterial adhesion rate with comparatively no cytotoxicity. Cell attachment on all alloys was similar but the best spread was obtained on TZC-7A after 24 h. The developed alloy has good potential as an antibacterial implant material with combination of optimized properties.