Cellular responses of Saccharomyces cerevisiae to Silver Nanoparticles

Silver nanoparticles are increasingly finding wide applications in health care, electronics and biomedical instruments as well as in consumer products like cosmetics. Although the bactericidal properties of silver nanoparticles are well documented, there is scant data available on their effect on eukaryotic cells. We report results from experiments concerning the model organism Saccharomyces cerevisiae and its growth in the presence of silver nanoparticles. A novel method of nanoparticle synthesis in yeast malt media was achieved. Characterization of particles by transmission electron microscopy and X-ray diffraction revealed a mean particle size of 8.6 nm. The minimum inhibitory concentration (MIC) and the minimum killing concentration (MKC) of the nanoparticles were 48.51 mu g/ml and 70.07 mu g/ml respectively. Growth of cells, in presence of nanoparticles, showed significant changes in growth rate and doubling time. Effect on total cellular protein, free amino acid and RNA content similarly showed deviations from cells devoid of nanoparticle stress. Electron micrographs revealed changes in plasma membrane which was further confirmed by an in vitro permeability assay. Saccharomyces cerevisiae could be an efficient model for study of cellular responses and toxicity of nanoparticles in eukaryotic cells.