Moderated crevice corrosion susceptibility of Ti6Al4V implant material due to albumin-corrosion interaction

Abstract

● Albumin adsorption was regulated by localized corrosion. ● Non-uniform albumin adsorption inhibited crevice corrosion of Ti6Al4V. ● Mechanism of albumin-corrosion interaction was disclosed. Localized corrosion of metallic biomaterials is a concerning problem for implant applications. In the present work, the interaction between localized corrosion of Ti6Al4V implant material and adsorption of bovine serum albumin (BSA) was investigated by electrochemical tests, surface morphological and compositional analysis. The artificial crevice was set up on the Ti6Al4V surface to simulate the crevice corrosion of metallic implants. The results show that the BSA adsorption is regulated by the heterogeneous metallic ion release resulted from the crevice corrosion. The negatively charged BSA prefers to aggregate at the interior of artificial crevice due to electrostatic interaction with the concentrated metallic cations in the crevice. In return, the non-uniform BSA adsorption can decrease the crevice corrosion susceptibility of the Ti6Al4V implant material, even though the presence of BSA accelerates the dissolution of passive films. For the Ti6Al4V alloys with artificial crevice, stable localized corrosion occurs after 96 h of immersion in the PBS free of BSA while no stable localized corrosion can be determined in the presence of 4% BSA. It is deduced that the presence of BSA can reduce the surface potential discrepancy between the crevice interior and the crevice exterior. The disclosed mechanism of albumin-corrosion interaction is vital to the localized corrosion control of metallic implants in clinical use.