Photodynamic Therapy Associated with a Blue Dye Papain-Based Gel and Evaluation of Its Degradation of Type I Collagen Fibers.

Objective: The aim of this in vitro study was to evaluate the degradation of type I collagen fibers after treatment with a papain-based gel associated with a blue dye (PapaMBlue) for use in antimicrobial photodynamic therapy. Materials and methods: For such, 60 bioabsorbable membrane sponge discs were used. Group 1 was the negative control group. In groups 2, 3, and 4, the papain-based gel PapaMBlue gel was applied all over the samples for 4min and irradiated using red laser (660 +/- 10nm) with 15, 30, and 40J/cm(2), respectively. In group 5, the papain-based gel was applied all over the samples for 4min. In group 6, the photosensitizing dye was applied all over the samples for 4min. The compositional analysis of the samples was performed using ATR-FTIR (attenuated total reflectance-Fourier transformed infrared spectroscopy). The data were statistically analyzed using ANOVA and Tukey's test (p<0.05). Results: Neither classic Papacarie nor the modified product with a photosensitizing agent (PapaMBlue) promoted collagen degradation. Conclusions: The irradiation of methylene blue added to papain gel with red light did not alter the chemical structure of type I collagen.