Novel Zircaloy nanomaterials with antibacterial activity

The outcome of an implant procedure largely depends on the implant's surface properties. Biomaterials are now required to have surfaces with multifunctionality such as favorable tissue integration and the ability to combat bacterial adhesion and colonization. Herein, we report on a simple approach to improving the antibacterial properties of zirconia nanotubes (ZrNT) coatings via decoration with silver nanoparticles (AgNp/Ag2O). This was done by electrochemical anodization of Zr-Ag alloy at a constant voltage in a fluoride-containing electrolyte. The modified ZrNTs were characterized using SEM, EDS, ToF – SIMS, and XPS to determine their structural morphology and chemical composition, and were further subjected to antibacterial testing The silver and zirconium ion release behavior was also monitored via ICP-MS. ZrNT decorated with AgNp/Ag2O exhibited strong antimicrobial activity (> 99 % bacterial killing) against both S. aureus and E. coli. Antimicrobial tests indicated that the antibacterial activity against the Gram-positive pathogen S. aureus could be improved by a factor of 100 compared to unmodified ZrNT while the unmodified ZrNT showed already a comparable reduction of viable Gram-negative E. coli achieved with the additional AgNp/Ag2O decoration. This modification strategy illustrates a simplified and effective approach toward optimizing the interface between the host environment and the biomaterial surface to meet the very important criteria of biocompatibility and antibacterial properties.