Durable antimicrobial coatings for hospital sink surfaces using hydrophobized TEMPO-oxidised cellulose nanofibre...

Effective microbial control in water-associated environments, such as hospital sinks, is critical for preventing the spread of antimicrobial resistance in healthcare settings. Antimicrobial coatings represent a promising means for microbial control; however, their application on water-associated surfaces is challenging. Therefore, durable antimicrobial coatings that retain efficacy under challenging conditions, such as frequent water flow, are needed. To address this challenge, this study focused on water-resistant coatings formed by a silicone oil Pickering emulsion composed of hydrophobized 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidised cellulose nanofibres (CNF). We evaluated the performance of antimicrobial agent incorporation into the coatings under conditions simulating hospital sink surfaces. Most formulations achieved 99% (≥ 2-log₁₀) reductions in the viable counts of Escherichia coli and Staphylococcus aureus. Among the agents with promising performance, benzisothiazolinone (BIT) localised as particulate inclusions within CNF matrices, and the coating conferred antimicrobial activity against multiple clinically relevant drug-resistant strains. Durability tests, including surfactant exposure and abrasion during cleaning, confirmed sustained antimicrobial performance after treatment. Under conditions simulating frequent water flow, the coating also exhibited superior antimicrobial performance compared with selected commercial coatings. Overall, this environmentally benign and easy-to-apply coating offers a promising strategy for mitigating antimicrobial-resistant bacteria in water-associated environments and demonstrates strong potential for practical infection-control applications.