Photoactivated Curcumin-Loaded Lipid Nanoparticles in Hydrogel: A Cutting-Edge Intracanal Medicament for Advanced Endodontic Therapy

Intracanal reinfections continue to pose a major challenge in endodontic treatment. Photodynamic therapy has emerged as a promising antimicrobial strategy. Regarding this, curcumin (CUR), a natural photosensitizer, shows potential in this context, but its application is hampered by poor solubility and rapid degradation. This study aimed to develop and characterize a CUR-loaded nanoparticle-enriched hydrogel to enhance its stability, sustain its release, and evaluate its antimicrobial efficacy upon photoactivation (PhAc). Curcumin-loaded nanoparticles were synthesized and incorporated into a hydrogel matrix, followed by characterization using scanning electron microscopy, Fourier-transform infrared spectroscopy, in vitro CUR release studies, and rheological analysis. Antibiofilm activity against <i>Enterococcus faecalis</i> was assessed under both photoactivated and non-photoactivated conditions. Cytocompatibility was analyzed through fibroblast viability assays and fluorescence staining. The CUR-containing hydrogel demonstrated a sustained release profile extending beyond 72 h. Rheological studies confirmed its shear-thinning behavior, ensuring injectability even after post-photoactivation. Antibiofilm assays revealed a significant reduction in <i>E. faecalis</i> biofilms, with PhAc formulations exhibiting markedly enhanced antibacterial efficacy compared to their non-PhAc counterparts. Cytocompatibility assays confirmed that all formulations, including those subjected to PDT, preserved fibroblast viability, indicating biocompatibility suitable for clinical use. In sum, the CUR-containing hydrogel exhibits properties that support its potential as an effective intracanal therapeutic, combining antimicrobial and photodynamic effects to help prevent reinfections in endodontic treatments.