Ion implantation of 109Ag stable isotope as a tracer in SS316L biomedical implant for failure detection

Abstract

Stainless steel alloys are widely used for biomedical applications ranging from surgical tools to biomedical implant prostheses. Apart from surgical failure, surface degradation (wear and corrosion) leading to poor osteointegration of materials are a major cause of the failure of these bioimplants. Detection of the implant failure, once it is placed inside the body, is very difficult and not so accurate. In this research, high-energy ion implantation is used to develop a tracer embedded alloy. In this novel approach, a stable isotope of silver ( 109 Ag) is embedded as a tracer in SS316L to detect and monitor its degradation. High energy ion implantation of 109 Ag isotope allows the ions to be embedded deep inside the SS316L surface. Accelerated and normal static immersion tests were performed in 30% H 2 SO 4 and simulated body fluid (SBF) to represent the surface degradation of the implant. These results show a correlation between the isotopic tracer releases with material degradation. Electrochemical corrosion tests demonstrate the ion-implanted specimens exhibit similar corrosion resistance as the bare specimens. In-vitro cytotoxicity assays indicated no significant difference between the cell viability on SS316L and 109 Ag ion-implanted samples. The MG-63 osteoblast cells cultured on 109 Ag ion-implanted SS316L show a significant enhancement in osteocalcin production compared to SS316L. • Embedding of 109 Ag stable isotope tracer into the SS316L substrate. • Maximum 109 Ag ion accumulated at a depth of 4 μm to 7 μm from the irradiated surface. • Rise in the concentration of 109 Ag correlated with the degradation of SS316L. • MG-63 cells showed good proliferation, differentiation and osteocalcin production on 109 Ag-SS316L implants.