A VITA Index for predicting cytocompatibility of metallic biomaterials based on ion release and toxicity

Biocompatibility and cytocompatibility are critical early considerations in the development of metallic biomaterials for implantable devices; however, conventional in vitro cytotoxicity evaluations typically assess corrosion behavior or cytotoxicity independently and fail to account for their coupled effects on metal-ion release-driven cytocompatibility. Here, we present a novel Velocity-Ion Toxicity-Affinity (VITA) Index-a quantitative and mechanistically informed framework that integrates electrochemical dissolution (corrosion) behavior with ion-specific cytotoxicity to evaluate in vitro biocompatibility governed by metal-ion release. By combining corrosion profiling with cell-based cytocompatibility assays (using osteoblasts and fibroblasts as a representative model), the VITA Index demonstrates first-order accuracy, capturing robust correlations between ion-release kinetics and cell viability across both established biomedical alloys and emerging materials, including high-entropy alloys. The VITA Index enables rapid and mechanistically informed screening of candidate metallic biomaterials and provides a practical framework for in vitro biocompatibility assessment, cytotoxicity prediction, and data-driven alloy design for future implant applications.