Osteogenesis stimulation by copper-containing 316L stainless steel via activation of akt cell signaling pathway and Runx2 upregulation

As a metallic orthopedic implant, 316L stainless steel (316L SS) is used extensively for its good resistance to corrosion and mechanical properties. However, it takes a long time to achieve osseointegration between 316 L SS and adjacent tissues due to its bio-inert characteristic. Hence, the aim is to improve the bio-adaption of 316 L SS. A good approach is to add elements to materials to improve their osteogenic capabilities by the appropriate release of ions. Hence copper-containing 316 L stainless steel (316L-Cu SS) was investigated in this work, where Cu is an essential trace element that can stimulates osteogenesis. It was found that 316L-Cu SS was bio-safe and did not affect the proliferation of co-cultured osteoblasts in comparison with 316 L SS. It increased cell apoptosis on day 1 but inhibited it on day 3, which cooperates with new bone formation processes. Osteoblasts extend themselves more quickly and in a better manner on the surface of 316L-Cu SS, wheneven more pseudopodia are present. Furthermore, the gene expression of alkaline phosphatase, collagen I and runt-related transcription factor 2 (Runx2) in osteoblasts cultured with 316L-Cu SS was significantly enhanced. Runx2 protein expression increased, and osteogenesis was stimulated by 316L-Cu SS via an Akt cell signaling pathway. In conclusion, 316L-Cu SS stimulates osteogenesis through activation of the Akt cell signaling pathway and the upregulation of Runx2. Thus, 316L-Cu SS is a promising material that may be used in surgical implants to stimulate osteogenesis. (C) 2019 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.