Longitudinal Raman spectroscopic analysis of ex-vivo healthy and thermally damaged skin: a pilot study

This is the authors' abstract. We don't add key points for this paper.

BACKGROUND: Raman spectroscopy is increasingly recognised as a label-free optical technique capable of characterising tissue biochemistry with high molecular specificity. While numerous studies have demonstrated discrimination between healthy and thermally damaged tissues, few have investigated the temporal stability and biochemical evolution of the same ex vivo tissue specimens during longitudinal analysis. METHODS: Healthy control and thermally damaged skin tissues were maintained under physiological culture conditions and repeatedly interrogated using an inVia Raman microscope (Renishaw, UK) over a seven-day period. Raman spectra were acquired from tissue specimens at multiple predefined time points using an 830 nm excitation laser, a 20× objective, at ∼20 mW, 60 s acquisition time over one accumulation. Three explant replicates from a single donor were analysed per group, with fifteen spectra collected from each specimen at every time point. Spectral preprocessing included cosmic ray removal, baseline correction, and Savitzky-Golay smoothing. Selected Raman features were evaluated descriptively across the repeated measurement period. RESULTS: Distinct Raman spectral differences between healthy/control (H/C) and thermally damaged tissues were observed throughout the study. Longitudinal analysis revealed temporal spectral variation while maintaining separation between healthy and burn tissues. Differences were observed in collagen-, protein- and lipid-associated Raman bands, with the H/C group generally exhibiting higher relative intensities for several selected features. CONCLUSIONS: This pilot study demonstrates the feasibility of repeated Raman spectroscopic interrogation of identical ex vivo healthy and thermally damaged tissue specimens over seven days. These findings establish a methodological framework for longitudinal Raman studies of ex-vivo tissue models and support further investigation into temporal spectral variation using Raman spectroscopy.