Osteogenic ability of Cu‐bearing stainless steel

Abstract A newly developed copper‐bearing stainless steel (Cu‐SS) by directly immobilizing proper amount of Cu into a medical stainless steel (317L SS) during the metallurgical process could enable continuous release of trace amount of Cu²⁺ions, which play the key role to offer the multi‐biofunctions of the stainless steel, including the osteogenic ability in the present study. The results ofin vitroexperiments clearly demonstrated that Cu²⁺ions from Cu‐SS could promote the osteogenic differentiation by stimulating the Alkaline phosphatase enzyme activity and the osteogenic gene expressions (Col1a1, Opn, and Runx2), and enhancing the adhesion and proliferation of osteoblasts cultured on its surface. Thein vivotest further proved that more new bone tissue formed around the Cu‐SS implant with more stable bone‐to‐implant contact in comparison with the 317L SS. In addition, Cu‐SS showed satisfied biocompatibility according to the results ofin vitrocytotoxicity andin vivohistocompatibility, and its daily released amount of Cu²⁺ions in physiological saline solution was at trace level of ppb order (1.4 ppb/cm²), which is rather safe to human health. Apart from these results, it was also found that Cu‐SS could inhibit the happening of inflammation with lower TNF‐α expression in the bone tissue post implantation compared with 317L SS. In addition to good biocompatibility, the overall findings demonstrated that the Cu‐SS possessed obvious ability of promoting osteogenesis, indicating a unique application advantage in orthopedics. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1433–1444, 2015.