Dual-responsive and renewable antimicrobial surfaces via catechol-based adhesion for dental unit water lines

Abstract

The narrow and challenging-to-clean properties of dental unit water lines (DUWLs) allows for unchecked bacterial growth, while conventional daily disinfection struggles to eradicate persistent bacteria, posing a significant health risk. However, the existing coating preparation methods fail to achieve a long-term antibacterial effect and are arduous to prepare, thus rendering them inapplicable in the clinical practice of DUWLs. Herein, we prepared a smart, catechol-based temperature/acid dual-responsive antibacterial surface, combining stimulus-responsive polymers with bactericide just by immersion on the inner face of pipes. The synergistic effect of poly(N-isopropylacrylamide) (PNIPAM) on chain conformation transformation greatly promotes short-term bacterial release in response to temperature switching to maintain the antibacterial properties of polylysine (PL). The acid sensitivity of the imine bond joining polymers to PA facilitates the degradation of old coating and the synthesis post-renewal of new coating, thereby enhancing the long-term anti-bacterial response of DUWL finishes. The surface exhibits antimicrobial performances as below: (i) killing ∼85.0 % of the attached bacteria, (ii) releasing ∼96.8 % of the bacteria killed under temperature switching, (iii) further releasing under acid environment and (iv) restores the bactericidal and release effects after recoating. Moreover, the coating still exhibits excellent antibacterial/release performance in the clinical setting. This research offers an efficient, straightforward approach for resolving surface-associated bacterial challenges in DUWLs.