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

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 (109Ag) is embedded as a tracer in SS316L to detect and monitor its degradation. Accelerated and normal static im-mersion tests were performed in 30 % H2SO4 and simulated body fluid (SBF) to represent the degradation of the implant. These results show a correlation between the isotopic tracer releases with material degradation. Elec-trochemical 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 109Ag ion-implanted samples. The MG-63 osteoblast cells cultured on 109Ag ion-implanted SS316L show a significant enhancement in osteocalcin production compared to SS316L.

Automated summary

Stainless steel alloys are commonly used in biomedical applications but surface degradation and wear can lead to failure of bioimplants. This research develops a novel approach using high-energy ion implantation to embed a tracer in the alloy for detecting and monitoring degradation. Accelerated and normal immersion tests show a correlation between isotopic tracer releases and material degradation. Electrochemical tests demonstrate similar corrosion resistance between ion-implanted and bare specimens, and cytotoxicity assays show no significant difference. Osteoblast cells cultured on ion-implanted SS316L show an enhancement in osteocalcin production.