The effectiveness of glycerol solutions for optical clearing of the intact skin as measured by confocal Raman microspectroscopy

The effect of glycerol solutions of different concentrations and exposure times on the optical clearing efficiency in intact pig skin has been studied in the analysis of Raman spectra recorded at different depths. It has been found that a solution of 80% glycerol and 20% dimethylsulfoxide penetrated through the stratum corneum during 45 min. The increase in optical clearing has been achieved by using mixtures of optical clearing agents with dimethylsulfoxide and distilled water. Thus, the greatest optical clearing efficiency was observed when using a mixture of 60% glycerol and 40% water for 45 min (an increase of 3.4 times at a depth of 80 $\mu$m). Thus, it has been shown that it is possible to control the skin optical parameters at a depth of about 80 $\mu$m using the method of confocal Raman microscopy.