EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Precious metal based bulk metallic glasses (BMGs) exhibit enhanced mechanical strength, high corrosion resistance, and excellent superplastic forming capability. Such property combination makes them particularly attractive for medical, space, and watchmaking applications. In addition, for medical applications, the Cu and/or Ag bearing BMGs could have an antibacterial effect through a controlled release of these ions.
In dental and medical applications, the colonization and growth of bacterial biofilms on the surface of biomaterials is in fact a big problem that burdens the health system with important patient suffering and economic losses.

In this study, we explore the release of metallic ions, with a special interest in the antibacterial Cu ions, from partially crystallized Pt- and Pd- BMGs. BMGs with nominal compositions Pt57.5Cu14.7Ni5.3P22.5 and Pd43Cu27Ni10P20 were prepared as 3 mm thick plates by copper mold casting. Some of these samples were subjected to isothermal heating at different conditions in order to produce various crystalline fractions. Following ISO 10271 for metallic dental materials, the samples were immersed in a 0.1 M lactic acid and 0.1 M NaCl solution for 7 days at 37°C for the ion extraction. The metal ions extracted into the solution were quantified by ICP-MS.
Ion release of the Pt-BMGs does not vary significantly with crystallinity and stays at a low level. Pd-BMGs, by contrast, show a pronounced dependence of Cu ion release on crystal fraction, varying between 0.15 and 2.62 $\mu g/cm^{2}$ for, respectively, fully amorphous and highly crystalline samples.

This study presents a promising new strategy to provide Pd-BMG biomaterials with possible antibacterial properties. Future studies will determine the direct effect of Cu ion release on dental and medical relevant biofilms.