Photobiocidal Activity of TiO<sub>2</sub>/UHMWPE Composite Activated by Reduced Graphene Oxide under White Light.

Jeong, Sang Bin; Heo, Ki Joon; Yoo, Jae Hyun; Kang, Dong-Gi; Santoni, Leonardo; Knapp, Caroline E; Kafizas, Andreas; Carmalt, Claire J et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Herein, we introduce a photobiocidal surface activated by white light. The photobiocidal surface was produced through thermocompressing a mixture of titanium dioxide (TiO<sub>2</sub>), ultra-high-molecular-weight polyethylene (UHMWPE), and reduced graphene oxide (rGO) powders. A photobiocidal activity was not observed on UHMWPE-TiO<sub>2</sub>. However, UHMWPE-TiO<sub>2</sub>@rGO exhibited potent photobiocidal activity (>3-log reduction) against <i>Staphylococcus epidermidis</i> and <i>Escherichia coli</i> bacteria after a 12 h exposure to white light. The activity was even more potent against the phage phi 6 virus, a SARS-CoV-2 surrogate, with a >5-log reduction after 6 h exposure to white light. Our mechanistic studies showed that the UHMWPE-TiO<sub>2</sub>@rGO was activated only by UV light, which accounts for 0.31% of the light emitted by the white LED lamp, producing reactive oxygen species that are lethal to microbes. This indicates that adding rGO to UHMWPE-TiO<sub>2</sub> triggered intense photobiocidal activity even at shallow UV flux levels.

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