title: Synergistic antibacterial activity of chitosan-silver nanocomposites on Staphylococcus aureus.
abstract: The approach of combining different mechanisms of antibacterial action by designing hybrid nanomaterials provides a new paradigm in the fight against resistant bacteria. Here, we present a new method for the synthesis of silver nanoparticles enveloped in the biopolymer chitosan. The method aims at the production of bionanocomposites with enhanced antibacterial properties. We find that chitosan and silver nanoparticles act synergistically against two strains of Gram-positive Staphylococcus aureus (S. aureus). As a result the bionanocomposites exhibit higher antibacterial activity than any component acting alone. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of the chitosan-silver nanoparticles synthesized at 0 °C were found to be lower than those reported for other types of silver nanoparticles. Atomic force microscopy (AFM) revealed dramatic changes in morphology of S. aureus cells due to disruption of bacterial cell wall integrity after incubation with chitosan-silver nanoparticles. Finally, we demonstrate that silver nanoparticles can be used not only as antibacterial agents but also as excellent plasmonic substrates to identify bacteria and monitor the induced biochemical changes in the bacterial cell wall via surface enhanced Raman scattering (SERS) spectroscopy.
authors.affiliation: Nanobiophotonics Center, Interdisciplinary Research Institute in Bio-Nano-Sciences and Faculty of Physics, Babes-Bolyai University, T Laurian 42, 400271 Cluj-Napoca, Romania. monica.potara@phys.ubbcluj.ro
authors.forename: Monica
authors.initials: M
authors.lastname: Potara
authors.forename: Endre
authors.initials: E
authors.lastname: Jakab
authors.forename: Annette
authors.initials: A
authors.lastname: Damert
authors.forename: Octavian
authors.initials: O
authors.lastname: Popescu
authors.forename: Valentin
authors.initials: V
authors.lastname: Canpean
authors.forename: Simion
authors.initials: S
authors.lastname: Astilean
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology*; D004357:Drug Synergism; D006801:Humans; D053761:Nanocomposites / Q000737:chemistry / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry* / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D048271:Chitosan