Gold-Based Nanoparticles as an Additive for Combating Drug-Resistant Escherichia coli in Water-Based Paint

Abstract

The rise of drug-resistant Escherichia coli (E. coli) poses a major challenge in both healthcare and materials science, particularly with regard to surface hygiene. Wall surfaces, particularly those in high-contact areas, can act as breeding grounds for bacterial growth and serve as potential transmission points for harmful bacteria, including drug-resistant strains. Beyond health concerns, bacterial contamination can cause aesthetic damage through bacterial-induced discoloration, which is another significant problem. To address this issue, we proposed that incorporating gold-based nanoparticles (DP1-GNPs) as an antimicrobial additive in paints could enhance antibacterial properties, especially against drug-resistant bacterial strains. This study aimed to evaluate the antibacterial effectiveness of DP1-GNPs incorporated into paint against drug-resistant E. coli BAA-1161, which was used as a drug-resistant bacterial model strain. We systematically compared the bacterial viability on paint films with and without DP1-GNPs under nonscrubbed and scrubbed conditions. The results showed a reduction in bacterial viability upon immediate exposure on both scrubbed blank water-based paint without antimicrobial agents (BP) but containing DP1-GNPs (BP/DP1-GNPs; 69.55 ± 5.39% bacterial viability) and nonscrubbed BP/DP1-GNPs films (85.15 ± 4.11% bacterial viability). Notably, when the scrubbed BP/DP1-GNPs films were further treated with DP1-GNPs shield, the viability of E. coli BAA-1161 was reduced to 47.04 ± 2.41%, indicating the enhanced antibacterial performance of the shielded surface. Importantly, cytotoxicity tests indicate that lixiviated products of paint films containing DP1-GNPs were nontoxic to human skin fibroblasts, suggesting their safety on surfaces with frequent human contact. These findings highlight the potential of DP1-GNPs as antimicrobial additives in paint formulations, offering a promising strategy for combating drug-resistant bacterial contamination on painted surfaces.