Salt-responsive polyzwitterion brushes conjugated with silver nanoparticles: Preparation and dual antimicrobial/release properties

Abstract Attachment and colonization of bacteria on surfaces seriously impact human health as well as numerous technologies. In this contribution, a new zwitterionic monomer, 3-(dimethyl(4-vinylbenzyl)ammonio)butanesulfonate (DVBABS), was synthesized and a polymeric coating that not only kills bacteria but also releases them afterwards was constructed through rapid deposition of polydopamine (PDA) followed by in situ synthesis of Ag nanoparticles (NPs) and finally by grafting of polyDVBABS brushes using ARGET-ATRP (activators regenerated by electron transfer for atom transfer radical polymerization). The PDA catechol groups immobilized the Ag NPs, which were responsible for the inhibition of bacterial growth, and a change from water to salt solution effected a reversible conformational transition of the polyzwitterion, which was responsible for bacterial release. For both Escherichia coli (E. coli) and Staphylococcus (S. aureus), the dual-function coating can kill ≥99% of attached bacteria and then rapidly release ≥95% of all attached bacteria. Both functions were well retained over several cycles of killing and release. Based on the substrate-independent adhesion of PDA coatings, exemplified here for titanium, cotton textile, polypropylene and polydimethylsiloxane surfaces, a broad spectrum of applications are envisaged.