Cytocompatibility of Ti3AlC2, Ti3SiC2, and Ti2AlN: In Vitro Tests and First-Principles Calculations.

Herein, the cytocompatibility of selected MAX phases, Ti3AlC2, Ti3SiC2, and Ti2AlN, were systematically evaluated using in vitro tests for the first time. These phases were anoxic to preosteoblasts and fibroblasts. Compared with the strong viable fibroblasts, the different cellular responses of these materials were clearly distinguishable for the preosteoblasts. Under an osteoblastic environment, Ti2AlN exhibited better cell proliferation and differentiation performance than Ti3AlC2 and Ti3SiC2. Moreover, the performance was superior to that of a commercial Ti-6Al-4V alloy and comparable to that of pure Ti. A possible mechanism was suggested based on the different surface oxidation products, which were determined from the binding energy of adsorbed Ca2+ ions using first-principles calculations. Compared with the partially oxidized TiCxOy layer on Ti3AlC2 and Ti3SiC2, the partially oxidized TiNxOy layer on the Ti2AlN had a stronger affinity to the Ca2+ ions, which indicated the good cytocompatibility of Ti2AlN.