Tailored assembly of vinylbenzyl N-halamine with end-activated ZnO to form hybrid nanoparticles for quick antibacterial response and enhanced UV stability

Weak UV light stability of N-halamine-based materials leads to severe antibacterial capacity fading, and further limits their practical applications. Herein, atom transfer radical polymerization (ATRP) method was firstly employed to fabricate ZnO-poly[3-(4-vinylbenzyl)-5,5-dimethylhydantoin] (ZnO-PVBDMH) nanoparticles through a 2-bromoisobutyryl bromide group linked onto the surface of ZnO nanoparticle (ZnO-BIBB). Morphology and structures of ZnO-PVBDMH nanoparticles in relationship to their chemical composition were investigated. Prominent UV light stability results confirmed that ZnO nanoparticles significantly reduce the chlorine loss of N-halamine upon UV irradiation, and about 79% of the active chlorine could be recharged after 72 h of irradiation. The ZnO-PVBDMH-Cl NPs with 1.62 wt% oxidative chlorine could sterilize 99.96% Gram-positive Staphylococcus aureus (3.38 log) and 100% Gram-negative Escherichia coli O157: H7 (7.39 log) within 30 min. After 24 h of UV irradiation, the ZnO-PVBDMH-Cl NPs could still inactivate 97.17% E. coli O157: H7 within 60 min. The nanoparticles also show excellent in vitro cell viability owing to the unique hybrid structures. The excellent photocatalytic capability of ZnO-PVBDMH NPs was investigated by determining the decomposition of the methylene blue (MB) solution. As an easy and efficient way of modifying nanoparticles, such technique can further extend the application of N-halamine monomers in other polar substrates for antibacterial functionalization. (C) 2019 Elsevier B.V. All rights reserved.