Multi‐Dimensional Assessment and Analysis of Thermal Damage in Skin Tissue by Femtosecond Laser Welding

In this study, four thermal damage assessment methods were used to investigate the thermal damage caused by femtosecond lasers on skin tissues. Collagen volume and texture characteristic parameters of the skin microstructure were calculated and analyzed by Masson staining of skin samples and grayscale covariance matrix. The skin thermal damage parameters and the degree of skin protein denaturation were analyzed by the Arrhenius equation and Raman spectroscopy. The results show that as the laser power increases or the scanning speed decreases, the collagen volume of skin tissue decreases, the angular second-order moments and correlations increase, the entropy value and contrast decrease, the parameters of thermal damage of skin tissue increase, the intensity of the characteristic peak spectral bands of the Raman spectrum of skin tissue in regions 1 and 4 decreases, and the degree of protein denaturation increases, which indicates that the degree of thermal damage of skin tissue increases.