Voltage and wear debris from Ti-6Al-4V interact to affect cell viability during in-vitro fretting corrosion.

Fretting corrosion (or mechanically assisted corrosion, MAC) is a major corrosion mechanism in modular orthopedic implants. There is a complex interplay between fretting corrosion and the surrounding biological environment that includes particle generation and electrochemical potential excursions and currents. The goal of this work is to directly investigate the effects of fretting on cells in vitro. Using an in vitro fretting device, MC3T3 preosteoblasts were cultured onto Ti-6Al-4V disks adjacent to the fretting site. Under fretting corrosion conditions, cell viability dramatically decreased to 0.5% with the voltage drop reaching -1 V (vs. Ag/AgCl). Under the same fretting corrosion conditions, but potentiostatically holding the Ti-6Al-4V sample surface potential to -300 mV or -50 mV (vs. Ag/AgCl), the cell viability increases to 70% and 38%, respectively. The results indicate that both cathodic potential excursions and wear debris play significant roles in affecting cell viability. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 160-167, 2018.