Synthesis, antibacterial activity and action mechanism of silver-based nanomaterials with thermosensitive polymer-decorated graphene oxide as a stable support

Silver-based antibacterial nanomaterials still have challenging problems of easy aggregation and low antibac-terial activity although they have attracted considerable attention because of their unique antimicrobial activity. Graphene oxide (GO) is a good carrier for preparing diverse nanocomposites owing to its huge specific surface area, oxygen-rich groups, high water dispersibility and biocompatibility. Herein, temperature-sensitive copol-ymer decorated graphene oxide (GO@P) was prepared as an efficient support of silver nanoparticles (AgNPs). The copolymer P(NIPAM-co-MQ) with functional coordination group of 5-(2-methacryloylethyloxymethyl)-8-quinolinol (MQ) can well stabilize the AgNPs formed in situ to avoid their aggregation and obtain uniform and smaller size metal particle on GO surface. The as-constructed GO@P@AgNPs nanocomposite had good broad-spectrum antibacterial activity. GO@P@AgNPs exhibited excellent rapid and cyclic antibacterial properties with the MIC values of 125 and 62.5 & mu;g/mL against Gram-positive S. aureus Gram-negative E. coli, respectively. Moreover, the nanocomposite can completely kill both tested bacteria within one hour. After five cycles of use, its antibacterial efficiency can still reach over 70 %. It is found that the antibacterial properties of GO@P@AgNPs are dependent on temperature, concentration of nanomaterials and species of tested bacteria. This work supplies a substantial foundation for the research and application of new high-efficiency nanosilver-based antibacterial agents.