Influence of Surface/Interface Properties of Nano- and Microscale Oxide Particles on Their Antibacterial Action.*

There is a growing interest in alternative antibacterial agents such as metal oxide particles. For many oxides, the antimicrobial action is well established, although the mechanisms of this cytotoxicity are largely unknown, with a possibility that antimicrobial activity of oxide particles occurs through multiple mechanisms. Moreover, there is a significant lack of understanding of the role and nature of the local bacterial environment in mediating/hindering antibacterial interactions. In our work, to address the mechanisms of interactions between oxide surfaces, cell membranes and bacterial growth media we employ hydrothermally grown nano- and microparticles of undoped and doped ZnO, β-Ga₂O₃, as well as GaOOH. We produce particles with controllable morphologies and relative abundances of surfaces with specific polarities. The antimicrobial assays of our particles are performed with Escherichia coli and Staphylococcus aureus. We run pre- and post-assay comparative studies of the oxide specimens themselves using such characterization techniques as electron microscopy, energy-dispersive X-ray spectroscopy, surface photovoltage, photoluminescence spectroscopy, Raman spectroscopy, etc.