In the current study, an excitation laser source emitting at 785 nm (100 mW, CW) was used to obtain ex vivo fluorescence of endogenous melanin in pigmented skin with benign, dysplastic and malignant cutaneous lesions. The samples were obtained after surgical removal during standard excision procedure and split for spectral analysis and histological verification. The samples of benign (BN-5) and dysplastic (DN-3) nevi and of malignant melanoma (MM-7) were used as representative for harmless/harmful cutaneous neoplasia with a similar melanin pigmentation. Emission in the range 800 – 1100 nm was detected and compared using a USB4000 micro-spectrometer (Ocean Optics Inc., USA). The photobleaching dynamics was observed for the emission maxima at 825 nm for 10 minutes with a step of 20 s. These near-IR autofluorescence spectra may be assigned to a single fluorophore if appropriate excitation wavelength is applied, which simplifies the rapid analysis related to the appearance and concentration evaluation of a given type of endogenous fluorophore, as well as allows the evaluation of some parameters, such as photobleaching dynamics, as a diagnostic indicator assessing the tissue state. A diagnostic accuracy of 93.3% was achieved for MM lesions validation when the NIR fluorescence intensity and photobleaching rate values were used to discriminate between nevi and melanoma lesions.

Investigation and characterization of the basic polarimetric characteristics on different cutaneous degenerative conditions (Syndrome of Raynaud, lupus, and psoriasis) histological samples was carried out to evaluate the potential for analysis of skin degenerative alterations. Stained and unstained histological samples from the different groups of degenerative conditions of the skin were histologically addressed and were used for polarimetric measurements. Diode laser linearly polarized beam at 635 nm was used for irradiation of the samples and polarimeter, working in the visible spectral range 400-700 nm was applied for polarimetric measurements. We will present the results of histology tissue slides evaluation through Stokes polarimetry in transmission geometry. These studies allow analysis of skin degenerative alterations in collagen anisotropic structuration in extracellular matrix and could be used as indicators of the tissue condition. Therefore, the present work would make possible the establishment of database with polarimetric features of degenerative skin conditions.