An injectable κ-carrageenan hydrogel carrier maintains antibiofilm activity while supporting dental pulp-derived stem cell viability in a dentin-based model.

OBJECTIVES

To evaluate the antibiofilm activity of a κ-carrageenan hydrogel (κC) used alone or as a carrier for calcium hydroxide (CH) against mono- and dual-species dentin biofilms, and to assess its cytocompatibility in dental pulp-derived stem cells (DPSCs) within a regenerative endodontic model.

METHODS

Antibiofilm activity was examined in vitro using monospecies and dual-species cultures of Fusobacterium nucleatum and F. nucleatum + Porphyromonas gingivalis exposed to 2.5% κ-carrageenan hydrogel, CH, or κC+CH, with assessment of broth turbidity and crystal violet biomass. An ex vivo regenerative endodontic model was established using infected dentin segments, and specimens were treated with 2.5% κ-carrageenan hydrogel, CH, or κC+CH. Antibiofilm effects were assessed using alamarBlue™ (resazurin-based) viability assay, confocal Live/Dead imaging, and scanning electron microscopy. Cytocompatibility was evaluated in dental pulp-derived stem cells by MTT, Live/Dead imaging, and alkaline phosphatase activity.

RESULTS

κC reduced bacterial viability, while CH showed greater antibacterial activity at later time points. In the ex vivo dentin model, CH and κC+CH reduced biofilm viability relative to control, with κC+CH showing sustained activity in both mono- and dual-species conditions. Quantitative analysis showed reduced biofilm biomass with CH and κC+CH, while κC alone was similar to the control. CH decreased DPSC viability, whereas κC+CH maintained viability near control levels and increased alkaline phosphatase activity.

CONCLUSIONS

κC hydrogel showed antibiofilm activity while supporting DPSC viability. When used as a carrier for CH, κC maintained strong antibiofilm activity and showed improved cytocompatibility relative to CH alone, supporting further evaluation in regenerative endodontic-relevant models.

CLINICAL SIGNIFICANCE: A κ-carrageenan carrier may improve early antibiofilm activity of calcium hydroxide while reducing its cytotoxicity toward dental pulp stem cells.