Genotoxicity of gold nanoparticles functionalized with indolicidin towards Saccharomyces cerevisiae

The toxic effects of gold nanoparticles surface-functionalized with the antimicrobial peptide indolicidin (AuNPs-indolicidin) towards the yeast Saccharomyces cerevisiae, one of the major eukaryotic model organisms, have been evaluated. Growth and survival, genotoxicity, as measured by comet assay, and expression of the YCA1, an apoptosis indicating gene, following 72 hr exposure of yeast to AuNPs-indolicidin, and to AuNPs and indolicidin alone have been examined. The gold nanoparticles exerted toxicity with DNA damage, accompanied by reactive oxygen species production (ROS), but they do not inhibit yeast growth and viability. Genotoxicity was less pronounced for surface-functionalized nanoparticles, showing that S. cerevisiae is quite resistant to the complex AuNPs-indolicidin. A progressive reduction of the genotoxic effect was observed along 72 hr exposure, presumably due to the activation of DNA repair mechanisms. These findings suggest the occurrence of a physiological protective response of S. cerevisiae towards nanoparticles, thereby providing useful information to the assessment of the environmental impact of metal nanoparticles.