Mineral trioxide aggregate enriched with iron disulfide nanostructures: an evaluation of their physical and biological properties

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.

Anti-Inflammatory and Antibacterial Activity of the Chitosan/Chlorhexidine Gel Commercial Preparation for Postexodontia Treatment: An In Vitro Study

Objective  The present study aimed to assess in vitro the antibacterial activity, cytotoxicity, and the expression of prostaglandin E ₂ (PGE ₂ ) of Bexident post topical gel (BP).

Materials and Methods  The broth dilution test was performed to analyze the antimicrobial activity of BP against Staphylococcus aureus , Escherichia coli , and Streptococcus mutans . Minimal bactericidal concentrations (MBCs) and minimal inhibitory concentrations (MICs) were assessed. Cytotoxic activity was performed by the MTT (tetrazolium dye) method on human gingival fibroblast (HGF), human bone cells (HBC), and human pulp cells (HPC) (from primary cell culture) and HGF-1 from American Type Culture Collection. The expression of PGE ₂ produced by RAW 264.7 cells was determined by ELISA utilizing an Enzyme Immuno-Assay Kit.

Statistical Analysis  Shapiro–Wilks normality test and Mann–Whitney U test were performed for all data.

Results  The MBCs of BP for S. aureus , E. coli , and S. mutans were found at 25, 50, and 12.5%, respectively. The MICs for the same strains were found at 12.5, 25, and 3.125%. The CC ₅₀ of BP gel for HBC, HPC, and HGF, and HGF-1 were 12.5 ± 1.09, 0.37 ± 0.02, 0.35 ± 0.02, and 20.4 ± 0.02%, respectively. The levels of expression PGE ₂ produced by RAW 264.7 cells treated with IL-1β exhibit an inverse dose-dependent effect on the concentrations of BP gel used.

Conclusion  Our results indicate that the BP gel has a great antibacterial effect, adequate biocompatibility, showing a decrease in the expression of PGE ₂ on cells with previously induced inflammation. Due to the above, its use as a healing agent after oral surgery seems to be adequate.