Antibacterial performance of nanosecond laser irradiated zirconium-based bulk metallic glass

Bulk metallic glasses (BMGs) have garnered significant attention in recent decades due to the outstanding physical, chemical, and biomedical characteristics. The biomedical application of metallic glass also received extensive attention. This report investigates the interplay among antibacterial performance, crystallization and processing parameters of Zr-based bulk metallic glass (Zr-BMG) following nanosecond laser irradiation. We examined surface morphology, crystallization behavior, surface quality, binding energy, and ion release properties post-laser irradiation. Additionally, we evaluated the generation of reactive oxygen species upon immersion of Zr-BMG in phosphate-buffered saline using the 2',7'-dichlorofluorescin diacetate method. Staphylococcus aureus was chosen to assess Zr-BMG's antibacterial performance, while mouse osteoblasts were utilized to investigate in vitro cytotoxicity. Our findings revealed that at laser energy intensities below 0.08 J/mm², the amorphous structure of Zr-BMG remained intact after irradiation. Moreover, laser irradiation significantly enhanced the antibacterial performance of Zr-BMG. The release rate of ion, concentration of reactive oxygen species, and antibacterial properties exhibited direct proportionality to laser energy intensity. However, surfaces exhibiting high antibacterial efficacy also displayed elevated cytotoxicity. The surface irradiated with a 7 μJ ablation pulse and 200 mm/s irradiation speed demonstrated a superior balance between antibacterial and cytotoxic properties while maintaining an amorphous state. We hope this research can provide theoretical reference and data support for the application of metallic glass in biomedical application.