Novel Insights Into Hair Structure and the Effects of Chemical Stressors on Hair and Skin Using Label-Free Advanced Light Microscopy

The study explored advanced label-free imaging techniques to better understand hair structure and the effects of chemical stressors. It developed methods using autofluorescence and fluorescence lifetime imaging to characterize hair's cellular structure, revealing differences in fluorescence lifetimes across cuticle layers and distinguishing between eumelanin and pheomelanin. These methods were applied to an unidentified hair and skin disorder, identifying poorly differentiated cuticle cells. The research also examined chemical depilatories, finding that potassium thioglycolate and guanidine carbonate caused significant hair expansion and structural damage. While these chemicals did not significantly affect cell differentiation or proliferation, they reduced HaCaT cell viability and damaged cornified envelopes, though the stratum corneum protected the living cells' viability and integrity.