THE EFFECT OF MAGNESIUM AND CALCIUM ON THE POTENTIAL CAPABILITIES OF PURE ZINC TO SERVE AS BIOABSORBABLE IMPLANT MATERIAL

The growing interest in using metals as biodegradable implants mainly relates to their attractive mechanical properties compared to conventional bioabsorbable polymers. However biocompatible candidates, tested in the last couple of decades, such as magnesium and Iron showed inadequate behavior that was manifested by an accelerated corrosion rate and detrimental corrosion products, respectively. The attention related to Zinc is due to its natural biocompatibility and its critical role in many common physiological processes. Unfortunately, pure zinc exhibits unsatisfactory mechanical strength for biomedical structural applications and reduced in-vivo corrosion rate that can encourage a chronic inflammatory response or alternatively encapsulation process within a fibrotic tissue. The present study aimed at examining the potential of two innovative zinc based alloys: Zn-1%Mg and Zn-1%Mg-0.5%Ca to serve as structural biodegradable implants. The results obtained in terms of cytotoxicity assays in in-vitro conditions clearly indicate that both alloys were adequate in terms of their toxic effect to cells. Furthermore, it was evident that the addition of Ca to Zn-1%Mg has a deteriorating effect on ductility and corrosion resistance due to the formation of CaZn₁₃ intermetallic phase. In principal both tested alloys can be considered as potential candidates for bioabsorbable implants.