Assessment of 2,2,6,6-tetramethyl-4-piperidinol-based amine N-halamine-labeled silica nanoparticles as potent antibiotics for deactivating bacteria.

Novel potent antibiotics, amine N-halamine-labeled silica nanoparticles (ANHLS NPs) based on 2,2,6,6-tetramethyl-4-piperidinol (TMP), were skillfully synthesized via the encapsulation of silica nanoparticles with amine N-halamine polymer for effective killing pathogenic bacteria. The particle size and coating thickness of amine N-halamine of ANHLS NPs were well controlled by tuning size of silica NPs and polymer encapsulation period, respectively. Effect of chlorination time on the oxidative chlorine content in ANHLS NPs was well elucidated by the aid of the modified iodometric/thiosulfate technique. Antimicrobial action of the ANHLS NPs on bacterial strain was evaluated using Staphylococcus aureus and Escherichia coli as model pathogenic bacteria. Bactericidal assessment showed that the ANHLS NPs exerted powerful bactericidal capability toward both two model bacteria. Time-kill assay demonstrated the significance of the oxidative chlorine content and contact time on antibacterial behavior. Size effect experiment displayed the decisive role of the size in controlling the biocidal activity. Plausible antibacterial mechanism of the ANHLS NPs against pathogenic bacteria was also discussed. Such a systematic investigation of the ANHLS NPs provides us a novel idea of making them the promising candidates for deactivating bacteria or even disease control.