Bacteria killing and release of salt-responsive, regenerative, double-layered polyzwitterionic brushes

Abstract

Antibacterial surfaces that not only can kill bacteria but also can release the dead bacteria have become one of most promising antibacterial strategies, but the realization of high efficiency, rapid response and long-term reusability of such surfaces remains many challenges. Herein, we reported new antibacterial surfaces with high killing and release capabilities based on a salt-responsive brush recently developed by our group. These surfaces consist of two polymer brushes with two-layer architecture, where the upper-layer bactericidal brushes (poly[(trimethylamino) ethyl methacrylate chloride], polyMETAC or poly[2-(tert-butylamino)ethyl methacrylate], polyTA) were built on background layer of salt-responsive polyzwitterionic brush (poly(3-(dimethyl(4-vinylbenzyl) ammonio) propyl sulfonate), polyDVBAPS) via sequential surface initiated atom transfer radical polymerization. By the combination in this manner, the bacteria attach/release function of polyDVBAPS and bactericidal function of polyMETAC/polyTA were successfully integrated, resulting in the smart surfaces which can reversibly kill and release bacteria in response to the switch between water and salt solution. Both two systems in this study, i.e. poly (DVBAPS-b-METAC) and poly(DVBAPS-b-TA), exhibit high bactericidal activity by killing more than 93% and highly efficient regeneration capability by rapidly releasing ∼90% of the attached bacteria. Specifically, such excellent antibacterial performance of poly(DVBAPS-b-TA) can be well retained even after four killing-release cycles, indicating the great potential in reusable biological materials and devices. Furthermore, the correlation between physicochemical properties of the two-layer brushes with their bactericidal efficiency and regenerative capability was also investigated and discussed.