In-vitro fretting tribocorrosion and biocompatibility aspects of laser shock peened Ti-6Al-4V surfaces.

[Display omitted] • Nano/sub-micron pores, along with topography changes from LSPwC, cues for controlling gene expression and cell adhesion. • Surface oxide is mostly composed of mainly Ti4+ and a small amount of Ti3+ is crucial for tribo-corrosion resistance. • Synergistic porous topography and surface oxide crucial for tribo-corrosion, gene expression, and stem cell conformation. Laser shock peening without coating (LSPwC), a prospective surface modification technique for improving the mechanical aspects of Ti-6Al-4V alloy for automotive/aerospace sector, is also expected to dictate the efficiency of this material class for implant application. Here we unravel the impact of LSPwC on Ti-6Al-4V material surface characteristics, in-vitro tribocorrosion and biocompatibility. Micrography shows the presence of nano and sub-micron sized pores after LSPwC process. The role of nano and sub-micron sized pores along with topography modification induced by LSPwC to serve as cues for controlling gene expressions, cell adhesion and activities offer novel insights in this research direction. A detailed X-ray photoelectron spectroscopy analysis detected local chemical non-stoichiometry with reduced number of oxygen diffusion channels. A crucial outcome of this oxide layer modification is the negative skewness (−0.55 ± 0.11) and reduced kurtosis (3.49 ± 0.14) of the surface, along with localized plastic deformation. These factors are correlated with the shift in potential during fretting tribo-corrosion from −800 to −250 mV after LSPwC, accompanied by a lower coefficient of friction of 0.4. Furthermore, the presence of well-spread cells and the up-regulation of beneficial genetic markers (Ki67) on LSPwC surfaces have the potential to form a better bone-material interface. The findings open new frontiers of the LSPwC-treated Ti-6Al-4V surface to synergistically modulate the tribocorrosion and biocompatibility aspects, with exciting possibilities for biomedical implants. [ABSTRACT FROM AUTHOR]