Antifouling and rechargeable antibacterial polyurethane modified with N-halamine for dental unit waterlines.

Bacterial contamination and biofilm formation in dental unit waterlines (DUWLs) present significant public health risks and economic burdens. Although standard chemical disinfection is commonly employed to sterilize DUWLs, it often fails to eradicate biofilms on the surfaces of polyurethane (PU). To address this, we developed a dual-functional PU surface possessing both antifouling and rechargeable antibacterial properties. The surface modification involved the initial conjugation of 1,6-diisocyanatohexane (HDI), followed by the sequential covalent grafting of polyethylene glycol (PEG) and 5,5-dimethylhydantoin (DMH). The resulting PU-HDI-PEG-DMH exhibited high hydrophilicity and reduced protein adsorption by over 50%. After chlorination, PU-HDI-PEG-DMH-Cl displayed durable biocidal efficacy through N-halamine-mediated contact- and release-killing mechanisms. Notably, this antibacterial capacity was fully rechargeable via standard clinical sterilization protocols. Therefore, this strategy offers a promising and sustainable solution to inhibit bacterial contamination and enhance the biosafety of DUWLs.