Methicillin-resistant Staphylococcus aureus (MRSA), characterized by its resistance to β-lactam antibiotics, including methicillin and penicillin, causes more than 120,000 deaths annually. MRSA infections, which are prevalent in medical facilities, are challenging to treat due to antibiotic resistance and the pathogen’s ability to survive on dry surfaces. Therefore, there is an urgent need to explore alternative strategies beyond traditional antimicrobial treatments. In this study, a novel self-cleaning film was developed by incorporating photocatalytic conjugates into cellulose-based materials, which were chosen for their biodegradability and cost-efficiency. This material inactivates MRSA by generating reactive oxygen species (ROS) under visible light. Its antibacterial properties were assessed on bacterial suspension in the PBS buffer and contaminated stainless-steel surfaces (n=3). Results showed that TcPP-TiO₂ (Tetrakis(4-carboxyphenyl) porphyrin)-Titanium dioxide (TcPP-TiO₂) conjugates expanded the responsive light wavelength of TiO₂ from the UV to the visible spectrum. Under 6000 lux illumination, ROS generated by the developed table cover caused a 4.79 ± 0.70-log CFU/mL (p ≤ 0.05) reduction in MRSA in a buffer within 24 hours. When the light intensity was reduced to 1000 lux, a significant 2.86 ± 0.12-log CFU/mL (p ≤ 0.05) reduction was reached, indicating the efficacy of this novel approach in low-light conditions. Overall, higher light intensity [MP1] promoted the generation of ROS, resulting in a better antibacterial effect on MRSA. Furthermore, when the film was applied to a dry, stainless-steel surface inoculated with MRSA, it decreased the bacteria population by 0.97 ± 0.25-log CFU/mL (p ≤ 0.05) on the stainless-steel surface within 2 hours of 3000-lux illumination. SEM pictures revealed that ROS destroys bacteria's cell walls and membranes. These findings underscore the potential for photocatalytic materials in controlling MRSA contamination on object surfaces in healthcare environments and food preparation facilities.

Zhiyuan Xu

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