Terapia fotodinâmica em biomembranas de quitosana contendo os conjugados dendríticos de poliglicerol-curcumina e poliglicerol-boro-curcumina para tratamento de feridas crônicas

Abstract

Photodynamic therapy enhances the antimicrobial action of dressings, delaying the time required for wound healing. Therefore, dressings are used with photodynamic therapy for wound treatment with a great benefit. The main objective of this Doctoral Thesis is to develop biomembranes containing antimicrobials that enhance their action through photodynamic therapy. The developed biomembrane consists of the chitosan biopolymer (Qui) and the antimicrobial agent’s curcumin (C) and the curcumin boron complex (BC). To increase the bioavailability of curcumin in the wound, a conjugate with the polyglycerol dendrimer (PGLD) was prepared. Therefore, the prepared biomembranes were Qui-PGLDC and Qui-PGLDBC. These biomembranes were characterized by spectroscopic techniques, Fourier transform infrared spectroscopy (FTIR); thermal, thermogravimetric analysis (TGA); structural, X-ray diffraction (XRD); morphological, scanning electron microscopy and fluorescence microscopy. FTIR showed the incorporation of the PGLDC and PGLDBC conjugates in the chitosan matrix. Biomembranes have lower thermal stability when compared to chitosan. The diffractogram of the biomembrane shows the X-ray pattern of the polymer matrix. SEM of the films showed a good dispersion of the conjugate in the polymer matrix. Fluorescent microscopy showed that both conjugates can be used in photodynamic therapy. UV-vis spectroscopy also was used to study the release kinetics of both conjugates were studied at different pH (2.0 and 7.4) at two temperatures 37°C and 40°C. Kinetic data were fitted to zero order, first order, Korsmeyer-Peppas and Higuchi. In general, the best fit found was to Korsmeyer-Peppas model, allowing to obtain information about diffusion process. The Qui-PGLDBC system showed Fickian behavior at 40°C, at both pHs. The highest diffusion rate constant kKP was found at 40°C. The microbiological study revealed that both conjugates have antimicrobial action against S. aureus, this activity being enhanced by the action of the Laser.