- Antimicrobial agents are being increasingly used in consumer soaps and detergents, despite a lack of data demonstrating their efficacy in such products. This study investigated the nature of the interaction between different crystalline structures of titanium dioxide nanoparticles and BTC, and explore which structure, if any, could be best used to mitigate the toxicity of BTC in various water systems. The nanoparticles used in the study were characterized using dynamic light scattering. To examine the toxicity of combinations of BTC and titanium dioxide nanoparticles, the 24-hour IC50 was determined and UV Vis spectrophotometry was used to measure cell growth in LB media containing varying concentrations of titanium dioxide nanoparticles and BTC at the IC50. For all crystalline structures and all concentrations in the supernatant treatment, there was a significant difference between cell growth in the treatment media and cell growth in BTC alone at the IC50. Growth was significantly inhibited when cells were treated with resuspended particles with BTC adsorbed onto the surface, indicating that for combinations of titanium dioxide nanoparticles and BTC found in aquatic ecosystems, special attention must be paid to organisms that spend the most time in sediment or near the bottom of bodies of water, where particles would settle out. There was no demonstrably significant difference in cell growth among different crystalline structures of nanoparticles at any concentration. However, P25, anatase, and rutile titanium dioxide nanoparticles are each capable of mitigating the toxicity of benzethonium chloride, and this finding could lead to novel methods for removing these potentially harmful chemicals from different water sources.
Keywords: nanoparticles, titanium dioxide, benzethonium chloride, antimicrobial,