Inflammatory Modulation and Odontogenic Responses of Riboflavin-loaded Hydrogel Applied for Regenerative Endodontics

This study investigated riboflavin as a bioactive signaling molecule with anti-inflammatory and odontogenic effects under inflammatory (+lipopolysaccharide [LPS]) and noninflammatory conditions (-LPS), and its incorporation into a novel hydrogel system for regenerative endodontics.

Human dental pulp stem cells were stimulated with E. coli lipopolysaccharide (LPS; 10 μg/mL, 7 days) to model chronic inflammation and treated with riboflavin (0, 3, 30, or 300 μM). Intracellular reactive oxygen species, nitric oxide production, migration, proliferation, collagen synthesis, and mineralized matrix deposition were evaluated. Based on these outcomes, a thermo-crosslinked Pluronic F127 hydrogel was developed with or without riboflavin. Release kinetics were assessed and the same biological assays were performed under ±LPS conditions using a transwell system.

Riboflavin reduced reactive oxygen species at all concentrations and decreased nitric oxide in a dose-dependent manner, with significant effects at 30 and 300 μM under +LPS. Riboflavin at 300 μM enhanced cell migration under both ±LPS and restored proliferation, particularly under +LPS. Collagen synthesis and mineralized matrix deposition were improved at all concentrations under +LPS. Riboflavin-loaded hydrogel showed initial burst release followed by sustained delivery. Under +LPS, riboflavin-loaded hydrogel significantly reduced oxidative stress, enhanced migration, proliferation, collagen synthesis, and mineralized matrix deposition, whereas unloaded hydrogel did not improve these deficits.

Riboflavin exerted potent anti-inflammatory and regenerative effects on inflamed human dental pulp stem cells. When incorporated into a controlled-release hydrogel system, it reduced inflammatory response and restored odontogenic properties to levels comparable with noninflammatory conditions, underscoring its potential as a cell-free tissue engineering strategy for vital pulp therapy.