Bioresorbable AgCe and AgCeLa alloys for adapted Fe-based implants

Implants often overtake body function just for a certain time and remain as an unnecessary foreign body or have to be removed. Thus, resorbable implants are highly beneficial to reduce patient burden. Besides established materials, Iron-(Fe)-based alloys are in focus due to superior mechanical properties and good biocompatibility. However, their degradation rate needs to be increased. Phases with high electrochemical potential could promote the dissolution of residual material based on the galvanic coupling. Silver (Ag) is promising due to its high electrochemical potential (+0.8 V vs. SHE), immiscibility with Fe, biocompatibility, and anti-bacterial properties. But to prevent adverse consequences the Ag-particles, remaining after dissolution of the matrix, need to dissolve. Thus, a bioresorbable Ag-alloy is required. Regarding the electrochemical potential and degradation behavior of binary alloys, Cerium (Ce) and Lanthanum (La) are well-suited considering their biocompatibility and antibacterial behavior. Accordingly, this research addresses AgCe and AgCeLa alloys as additives for Fe-based materials with adapted degradation behavior. Furthermore, degradable Ag-alloys combined with inert implant materials could enable the controlled release of antibacterial active Ag-ions.