Injectable Piezoelectric Hydrogel for Vital Pulp Therapy

Vital pulp therapy (VPT) seeks to preserve pulp vitality by using biocompatible with regenerative potential. This study tested the hypothesis that an injectable gelatin methacryloyl (GelMA) hydrogel containing piezoelectric barium titanate promotes odontogenic differentiation of dental pulp stem cells (DPSC) significantly better than a commercially available tricalcium silicate material used for vital pulp therapy. First, the light-curable, injectable piezoelectric hydrogel was engineered and characterized for its physicomechanical, piezoelectric properties and biocompatibility to DPSCs. The effect of this gel on the odontogenic differentiation of DPSCs was determined by measuring the expression level of key genes, compared to Biodentine XP. The hydrogel exhibited excellent injectability (<1 kgf of force), mechanical stability, and generated physiologically relevant voltages under cyclic loading mimicking mastication. MTT and ROS assays show no cytotoxic or damaging oxidative stress effects. When DPSCs were cultured over the materials under cyclic loading, the piezoelectric hydrogel significantly enhanced cell viability and upregulated COL1A1, DSPP, and DMP1 expression compared to Biodentine XP and non-piezoelectric hydrogel controls. These findings establish piezoelectric hydrogel as a self-powered, bioactive platform that converts physiological forces into regenerative bioelectric cues, offering a promising next-generation material for vital pulp therapy.