Development and characterization of alginate-derived bioadhesive films incorporated with anti-infective lectins for application in the treatment of oral candidiasis

Abstract

This study reports the characterization of alginate-derived bioadhesive films containing the lectins ConBr (from Canavalia brasiliensis Mart.) and MaL (from Machaerium acutifolium Vogel.). The anti-infective properties were evaluated using Tenebrio molitor larvae infected with an oral isolate of Candida albicans (CA40) (1 × 104 yeast/animal). Untreated larvae showed a median survival of 1.5 days and a survival rate of 40%. Both lectins (128 μg/kg/larvae) showed prophylactic effects (survival rates: 80%–90%); however, only MaL significantly increased larval survival (70%) in the treatment assays. Bioadhesive films were developed using sodium alginate, and each lectin was incorporated at 50 μg/mL of filmogenic solution. All films (pH 6.4) showed similar micromorphology with a slightly granular appearance. The lectins-loaded films exhibited more irregular surfaces than the control. The proteins were released in similar patterns. FTIR analysis confirmed the modification of sodium alginate due to the chemical interaction with lectins. All films exhibited a two-step weight loss pattern in TGA analysis. In the ex vivo mucoadhesive assay using bovine jugal mucosa, the highest value of maximum detachment force was found for ConBr-loaded films (0.56 ± 0.04 N) (p < 0.01). The other formulations showed similar adhesiveness (0.48 and 0.47 N). In general, the lectins did not induce significant changes in the physicochemical and mechanical characteristics of the alginate films. The data obtained in this work show, for the first time, the in vivo anti-infective effects of ConBr and MaL against C. albicans. The lectins-containing alginate films presented parameters compatible with their application in the oral cavity.