Synergistic antibacterial activity of chitosan–silver nanocomposites onStaphylococcus 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.

Solid-state encapsulation of Ag and sulfadiazine on zeolite Y carrier

“…Synergistic effects have also been demonstrated for chitosan-silver nanocomposites on strain of Staphylococcus aureus [10], for b-lactam antibiotics combined with silver nanoparticles and on strain of Escherichia coli [11].…”

Biofunctional Composites of Polysaccharides Containing Inorganic Nanoparticles

“…In this context bacterial cellulose offers several possibilities and the antimicrobial activity of the derived silver nanocomposites has been reported (Pinto et al, 2009).The polysaccharide plays an important role in these materials as stabilizer, preventing the aggregation of the nanoparticles. Moreover, polysaccharide nanocomposites may show a synergistic antibacterial activity and exhibit higher antibacterial activity than their separated components as recently observed for chitosan-silver nanocomposites (Potara et al, 2011). Also, despite the growing use of silver nanomaterials, the potential implications for human health and the environment are not completely clarified (Marambio-Jones & Hoek, 2010).…”

Preparation and characterization of chitosan-silver/hydroxyapatite composite coatings onTiO2 nanotube for biomedical applications

“…It easily forms chelate complexes with metals, such as zinc, Ag [12,13]. It has been reported that Ag ions and CS form complexes and show long-term antibacterial effectiveness against Escherichia coli and Staphylococcus aureus [13,14] be used in combination with HAp to further enhance bioactivity and tissue osteoconductivity [15,16]. Tang et al pointed out that CS/carbonated HAp composite coatings show improved cell morphology, adhesion, spreading and proliferation of human bone mesenchymal stem cells than carbonated HAp in vitro.…”