Confocal Raman Microspectroscopy of Skin: Study of Signal Variability and Effect of Excitation Wavelength

摘要

In order to evaluate the reliability of Raman analyses on skin, the present work aims to evaluate the variability of the Raman response on excised pigskin epidermis samples [1]. Acquisitions were performed with a Labram confocal microspectrometer (Horiba Scientific, Lille, France) at 3 wavenumbers: 532; 633 and 785 nm. Spectra were registered on and under skin surface at different depths. Point to point signal variability and spectra stability over time were examined. The underside of the skin was plunged in PBS (Invitrogen, UK) to maintain the hydration of the skin. Raman spectra were collected from -10 um (above the skin surface) to 50um (under the skin surface) with a 6 um step, using a 100X LF (Olympus, NA= 0.75) [2]. Each spectrum was acquired 2 times 10s, on the 400 cm~(-1) to 1800 cm~(-1) spectral range. A hot stage microscope maintained samples at 32°C [3]. Correction (CCD wavenumber response, baseline) and normalization on the amide I band (1630 – 1690 cm-1) were applied.