A Dual-Action Hydrogel System for Endodontic Repair and Infection Control

Objectives: This study endeavors to engineer and evaluate a dual-functional hydrogel system integrating gelatin methacryloyl (GelMA) and 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM-BF₄), with the objective of achieving optimal physicochemical properties, confirming biocompatibility, and enabling targeted disinfection of the root canal system while concurrently fostering stem cell-mediated tissue regeneration.

Materials & Methods: GelMA was synthesized via methacrylation of porcine-derived gelatin using methacrylic anhydride, followed by dialysis and lyophilization. Structural modification was confirmed through proton nuclear magnetic resonance (¹H NMR), with characteristic vinyl proton peaks appearing at ~5.5–6.0 ppm. The ionic liquid OMIM-BF₄ was incorporated into 10% (v/v) GelMA at concentrations of 0.1, 0.25, and 0.5 µL/mL. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed successful integration of OMIM into the GelMA network without disruption of primary functional groups. Injectability was assessed by extrusion through a 25-gauge needle to simulate clinical delivery. Disc-shaped hydrogels were fabricated to evaluate swelling behavior and enzymatic degradation. Swelling capacity was quantified following 24-hour immersion in phosphate-buffered saline (PBS), while degradation kinetics were monitored over a 14-day period in the presence of 1 U/mL collagenase.

Results: GelMA methacrylation was confirmed by ¹H NMR with a distinct peak at ~5.5–6.0 ppm corresponding to vinyl protons, and FTIR verified OMIM-BF₄ incorporation into GelMA without altering key functional groups. All GelMA–OMIM formulations demonstrated favorable injectability and comparable swelling profiles across groups. Notably, the 0.25 µL/mL OMIM concentration exhibited the greatest resistance to enzymatic degradation, showing significantly slower mass loss over the 14-day period in 1U/mL collagenase.

Conclusions: The dual-functional GelMA–OMIM platform represents a promising solution for injectable scaffold for root canal disinfection and regeneration.