Synthesis of biocompatible hydrogel of alginate-chitosan enriched with iron sulfide nanocrystals

This work aimed to synthesize and characterize a biocompatible hydrogel of alginate and chitosan enriched with iron sulfide nanocrystals. Three concentrations of iron sulfide nanocrystals (FeS₂NCs) 0.03905, 0.0781, and 0.2343 mg/ml were used. Gel swelling was determined using phosphate-buffered saline solution at 1, 2, 4, 6, 24, 48, and 72 h. The microstructure, the morphology, and the elastic strength were determined by optical microscopy, scanning electron microscopy, and rheological studies, respectively. The functional groups were identified through Fourier Transform Infrared spectroscopy. Biocompatibility was determined in a murine model; after seven days of subdermal inoculation, histological sections stained with H&E were analyzed, and then histopathological features were evaluated. All the compounds obtained showed a loss modulus lower than the storage modulus. The 0.2343 mg/ml FeS₂NCs hydrogel showed higher swelling than the control. In the in vivo evaluation, no adverse effects were found. The presence of FeS₂NCs was well tolerated in the subcutaneous tissue of mice, according to histopathological analysis. The hydrogels synthesized with added FeS₂NCs demonstrate a swelling ratio of 150 %, rheologically exhibiting gel-like behavior rather than viscous liquids. Furthermore, they did not present any adverse effects on the subcutaneous tissue.