Raman spectroscopy as a sensitive probe of soft tissue composition - Imaging of cross-sections of various organs vs. single spectra of tissue homogenates

The review offers detail data on the chemical composition of various organs, i.e. aorta, aortic valves, blood, brain, liver, lungs and kidney, obtained by Raman spectroscopy using two approaches. Raman imaging of tissues' cross-sections and single point measurements of homogenates were performed and critically compared. When the first method provides detailed, spatially resolved information about the distribution of various tissue components (proteins, lipids, haemoglobin, vitamin A, DNA, etc.), the other one is fast and does not require advanced sample preparation and costly spectrometers with imaging option, but, in fact, is less sensitive for inhomogeneous samples. Based on both approaches, the specific spectral features for a given organ were selected and assigned in order to serve as spectroscopic markers of particular soft tissues. Overall, the review shows the high potential of Raman imaging technique and limitations of single spectra measurements for the analysis of complex biological samples and their classification.