Ação da terapia fotodinâmica antimicrobiana na descontaminação da membrana de celulose bacteriana utilizada em tratamento de queimaduras

Abstract

Burn injuries are complex lesions that compromise the integrity of the skin barrier, favoring colonization by opportunistic microorganisms such as Candida albicans, which may impair the healing process and reduce the effectiveness of conventional antimicrobial therapies. Among the biomaterials used in burn treatment, bacterial cellulose membranes (BCM) stand out due to their high biocompatibility, excellent water-retention capacity, and ability to maintain a moist microenvironment favorable for tissue regeneration. However, their susceptibility to microbial contamination highlights the need for decontamination strategies capable of preserving their functional properties. In this context, Antimicrobial Photodynamic Therapy (aPDT) has emerged as a promising alternative based on the photoactivation of a photosensitizer (PS), generating reactive oxygen species with broad-spectrum antimicrobial activity, low cytotoxicity, and minimal risk of inducing microbial resistance. This study aimed to evaluate the efficacy of aPDT in the decontamination of bacterial cellulose membranes experimentally contaminated with C. albicans (ATCC 90028), assessing the interaction between the photosensitizer and the biomaterial, the reduction of microbial viability, and the biomechanical properties of the membranes following treatment. Initially, photosensitizer incorporation into the BCM was evaluated through spectrophotometric analysis at different experimental time points. Subsequently, post-treatment microbiological quantification was performed by colony-forming unit (CFU/mL) counting to determine the antimicrobial efficacy of aPDT. Finally, tensile mechanical tests were conducted to evaluate maximum force per area and deformation per area of the membranes. The results demonstrated an immediate interaction between the photosensitizer and the BCM, with a stable behavior maintained throughout the experimental period. Microbiological analysis revealed a significant reduction in the viability of C. albicans following aPDT application, confirming the effectiveness of the decontamination strategy. Biomechanical assays showed no statistically significant differences between the evaluated groups, indicating preservation of the membrane's mechanical properties after treatment. In conclusion, aPDT represents a safe and effective strategy for the decontamination of bacterial cellulose membranes, combining stable photosensitizer–biomaterial interaction, significant reduction in microbial viability, and preservation of the membrane's biomechanical properties. These findings reinforce its potential for future applications in burn treatment. Keywords: Antimicrobial Photodynamic Therapy; Candida albicans; Bacterial Cellulose Membrane; Burns; Methylene Blue; Microbial Decontamination.