Label free assessment of ultra-violet radiation induced damages in skin cells (Conference Presentation)

Changes in the cellular homeostasis in response to a stimuli, disease or therapeutic intervention are multifaceted in nature, and cannot be grasped by routinely employed targeted imaging that focuses on a small set of suspected molecules or genes. Novel approaches relying on global analysis of cellular features, from morphology to the composite biomolecular status (notably chemical composition and molecular conformation), is a pre-requisite for accurate monitoring of cellular processes. In the present study label-free profiling of normal skin fibroblasts (Hs895.Sk) exposed to sub-lethal doses of ultra-violet radiation has been performed using quantitative phase imaging and Raman spectroscopy. Spectral differences in the Raman fingerprint region indicates differences in the protein and nucleic acid composition. These differences were successfully utilized to develop an automated classification model based on principal component analysis. Distinct changes in the cellular morphology were observed and validated through quantitative phase imaging. Significant dose dependent differences in different biophysical parameters such as dry mass and matter density were observed. Combination of these two techniques, one suited for detection of subtle morphological/biophysical alterations while the other appropriate for capturing molecular perturbations, could pave the way to address issues of label-free monitoring of cellular responses in response to an external stimulus. These findings can provide an accurate understanding of different markers associated with radiation damage and would assist in providing a quantitative tool to our future studies on designing alternate diagnostic tools.