Toxicity and antibacterial assessment of chitosan-coated silver nanoparticles on human pathogens and macrophage cells

Abstract

Background: Pathogenic bacteria are able to develop various strategies to counteract the bactericidal action of antibiotics. Silver nanoparticles (AgNPs) have emerged as a potential alternative to conventional antibiotics because of their potent antimicrobial properties. The purpose of this study was to synthesize chitosan-stabilized AgNPs (CS-AgNPs) and test for their cytotoxic, genotoxic, macrophage cell uptake, antibacterial, and antibiofilm activities. Methods: AgNPs were synthesized using chitosan as both a stabilizing and a reducing agent. Antibacterial activity was determined by colony-forming unit assay and scanning electron microscopy. Genotoxic and cytotoxic activity were determined by DNA fragmentation, comet, and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays. Cellular uptake and intracellular antibacterial activity were tested on macrophages. Results: CS-AgNPs exhibited potent antibacterial activity against different human pathogens and also impeded bacterial biofilm formation. Scanning electron microscopy analysis indicated that CS-AgNPs kill bacteria by disrupting the cell membrane. CS-AgNPs showed no significant cytotoxic or DNA damage effect on macrophages at the bactericidal dose. Propidium iodide staining indicated active endocytosis of CS-AgNPs resulting in reduced intracellular bacterial survival in macrophages. Conclusion:The present study concludes that at a specific dose, chitosan-based AgNPs kill bacteria without harming the host cells, thus representing a potential template for the design of antibacterial agents to decrease bacterial colonization and to overcome the problem of drug resistance.

Anti-adhesion and Anti-biofilm Potential of Organosilane Nanoparticles against Foodborne Pathogens

“…The ability of 10 bacterial strains to form biofilms on polystyrene (PS) microtiter plates was evaluated by using the method described by Jena et al (2012) with some adaptations. Working culture of above bacteria was diluted 1:100 into fresh medium TSB.…”

Nanomaterials for removal of waterborne pathogens

“…Biologically originated chitosan nanoparticles or copper loaded chitosan nanoparticles and Chitosan NPs-AgNPs have been reported as antibacterial substances. Their positive surface charge and small size makes them stable in biological systems and they tend to bind with negatively charged bacterial membranes (study on S. choleraesuis, M. smegmatis, P. aeruginosa, S. typhi, and S. aureus) and causes cell leakage through membrane disruption (Qi et al, 2004;Sonawnae et al, 2012). Prodigiosin impregnated cellulose matrix has been found to remove E. coli (97.31%) and B. cereus (97.33%) (Arivizhivendhan et al, 2015).…”

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