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 316L SS and adjacent tissues due to its bio-inert characteristic.Hence,the aim is to improve the bio-adaption of 316L SS.A good approach is to add elements to materials to improve their osteogenic capabilities by the appropriate release of ions.Hence copper-containing 316L 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 316L 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.

Bio-Functional Cu Containing Biomaterials: a New Way to Enhance Bio-Adaption of Biomaterials

Although being an essential trace element required for human body health, Cu has long been seriously considered toxic when its amount exceeds certain limitation, which significantly limited the wide ap- plication of Cu in biomaterials. However, more and more bio-functions and benefits of Cu were found and confirmed, attracting the attention from biomaterials researchers in recent years. People have tried to immobilize Cu into biomaterials by various ways, in order to develop novel bio-functional Cu containing biomaterials with better bio-adaptions, and several different bio-functions of them have been demonstrated. This paper makes a review of the development of novel bio-functional Cu containing biomaterials, and focuses on their unique roles in enhancing bio-adaption of biomedical materials, including antibacterial performance, stimulating angiogenesis, promoting osteogenesis and inhibition of in-stent restenosis, aiming at proposing a prospective development direction for biomedical materials with better bio-adaptions.