Advanced Materials: TechConnect Briefs 2015Advanced Materials TechConnect Briefs 2015

Carbon Nano Structures & Devices Chapter 3

Silver coated carbon nanotubes regulate virulence gene expression in Salmonella Typhimurium

A.A. Chaudhari, S.R. Singh, S. Pillai
Alabama State University, United States

pp. 121 - 124

Keywords: silver coated carbon nanotubes, mechanism, virulence, gene, electron microscopy

Silver coated carbon nanotubes (AgCNTs) have several biomedical applications and their antibacterial activity against several multi drug resistant pathogens is well documented. However, the exact molecular mechanism for their antibacterial activity is yet to be explored. In the present study, antibacterial effect of AgCNTs against Salmonella enterica serovar Typhimurium was investigated using minimum inhibitory concentration (MIC) assay, quantitative growth analysis of salmonella exposed to AgCNTs, electron microscopy (EM) and molecular studies using qRT-PCR. The quantitative analysis showed the bactericidal effect of AgCNTs at 50 µg/ml whereas the concentrations such as 25, 12.5 and 6.25 µg/ml did not showed modest bactriostatic effect. EM analysis further revealed that when exposed to AgCNTs, bacterial cells internalized AgCNTs which resulted in to lysis of the cells. The molecular studies using qRT-PCR showed that the expression of some of the major virulence genes of salmonella were downregulated several folds compared to the non treated bacteria (~2-3 folds). Our results thus indicate that AgCNTs enter bacteria through damage to the cell membranes and may regulate the virulence gene expression in Salmonella Typhimurium.