Raman spectroscopy and atomic force microscopy study of cellular damage in human keratinocytes treated with HgCl2

Morphological and biochemical modifications of single human keratinocytes treated with HgCl2 at different concentrations were investigated by means of Raman micro-spectroscopy and atomic force microscopy techniques. Although the viability assay reveals that the exposure of keratinocytes to HgCl2 at a concentration of 10(-6) M has no cytotoxic effect, structural and biochemical modifications are revealed by Raman spectra and confirmed by atomic force microscopy images at such concentration. Such modifications consist of breakdown of both membrane lipidic layers and DNA bonds; fragmentation of DNA bases also occur, whereas proteins concentration is not influenced by HgCl2 exposure. These results are promising in view of the possibility to use Raman micro-spectroscopy, in combination with a remote optical probe, as a diagnostic tool for early detection of cellular damages induced by toxic agents exposure. Our findings also demonstrate that atomic force microscopy can be a valid and useful tool in studying the changes in morphology of cells when exposed to chemical stress. (C) 2006 Elsevier B.V. All rights reserved.