Search

As a metallic orthopedic implant, 316 L stainless steel (316 L 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.

Endothelialization is an important process after stenting in coronary artery. Recovery of the injured site timely can reduce the neointima formation and platelet absorbance, leading to a lower risk of in-stent restenosis. Copper is known to be critical in vascular construction. Thus a combination of copper with stent materials is a meaningful attempt. A copper bearing L605-Cu cobalt alloy was prepared and its effect on human umbilical vein endothelial cells (HUVECs) was evaluated in vitro in this study. It was found that HUVECs attached and stretched better on the surface of L605-Cu compared with L605, and the apoptosis of cells was decreased simultaneously. The migration and tube formation of HUVECs were also enhanced by the extract of L605-Cu. Furthermore, L605-Cu increased the mRNA expression of VEGF in HUVECs significantly. However it had no effect on the secretion of NO or mRNA expression of eNOS. The result of blood clotting test indicated that L605-Cu had better blood compatibility. These results above have demonstrated that the L605-Cu alloy is promising to be a new stent material with function of accelerating endothelialization. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 561-569, 2018.

Endothelialization is an important process after stenting in coronary artery. Recovery of the injured site timely can reduce the neointima formation and platelet absorbance, leading to a lower risk of in-stent restenosis. Copper is known to be critical in vascular construction. Thus a combination of copper with stent materials is a meaningful attempt. A copper bearing L605-Cu cobalt alloy was prepared and its effect on human umbilical vein endothelial cells (HUVECs) was evaluated in vitro in this study. It was found that HUVECs attached and stretched better on the surface of L605-Cu compared with L605, and the apoptosis of cells was decreased simultaneously. The migration and tube formation of HUVECs were also enhanced by the extract of L605-Cu. Furthermore, L605-Cu increased the mRNA expression of VEGF in HUVECs significantly. However it had no effect on the secretion of NO or mRNA expression of eNOS. The result of blood clotting test indicated that L605-Cu had better blood compatibility. These results above have demonstrated that the L605-Cu alloy is promising to be a new stent material with function of accelerating endothelialization. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 561-569, 2018.