Research Article
Dananjaya SHS, Godahewa GI,
Abstract
Nanocomposites exhibit high performance on antimicrobial activities and have the potential to be developed alternative antibiotics. In this study, antibacterial effects of chitosan silver nano composites (CAgNCs) were investigated using pathogenic Vibrio tapetis as a bacterial model. Agar disc diffusion and turbidimetric assay results showed that CAgNCs could inhibit the growth of V. tapetis in concentration depended manner. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs against V. tapetis were 50 μg/mL and 100 μg/mL, respectively. The field emission scanning electron microscopy (FE-SEM) images analysis of V. tapetis showed severe structural damage to cells after treating CAgNCs at 75 μg/mL compared to un-treated bacteria. Moreover, CAgNCs induce the intracellular ROS level, leakage of nucleic materials (RNA and DNA), decrease the cell viability and protein level in V. tapetis cells. Herein, we demonstrate that CAgNCs as effective antibacterial agent with capability to disrupt cell membrane, de-stabilize the membrane permeability, induce the oxidative stress and inhibit the expression of protein or synthesis of macromolecules. Overall results from this study suggest that mode of action of CAgNCs may be associated with excessive generation of ROS, loss in membrane integrity and inhibiting protein synthesis that cause the bacterial cell death.