Resumo:
The antimicrobial activity of curcumin associated with photodynamic therapy is a promising treatment for skin wounds. Curcumin metal complexes increase the antimicrobial properties and bioavailability of curcumin and decrease metal toxicity. This study aimed to synthesize curcumin metal complexes with zinc and copper as antimicrobial agents in chitosan membranes for photodynamic therapy. The synthesis was performed in a 1:1 curcumin:metal ion (Zn2+ or Cu2+) ratio under reflux for 1 hour at 80°C, using ethanol as a solvent. The complexes were dried and characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis spectroscopy, fluorescence spectroscopy, thermal analysis (DSC and TGA), scanning electron microscopy (SEM), and X-ray diffractometry (XRD). In addition, tests were performed to estimate the inhibition of bacterial growth. The complexes were incorporated into the chitosan matrix by mixing in solution to obtain the membranes. The chitosan membranes containing the Zn2+ or Cu2+ curcumin complexes were characterized by FTIR, TGA and DSC. The inhibition of bacterial growth associated with photodynamic therapy of the membranes was studied using a 440-480 nm laser. In vitro release tests of the complexes present in the membrane were performed, comparing them with pure curcumin. The physicochemical characterization confirmed the synthesis of Zn2+ and Cu2+ curcumin complexes. SEM showed that the morphology of the Zn2+ and Cu2+ curcumin complexes is different. The chitosan membranes containing the complexes showed potentiated bacterial inhibition by photodynamic therapy. The release behavior is controlled over time.
