Antimicrobial GH12-fibrin hydrogel for dental pulp regeneration: An in vitro study

Fibrin hydrogels hold great promise as drug delivery systems in tissue engineering, due to their biocompatibility, degradability, and injectability. However, their inability to prevent bacterial growth limits their usefulness in infection-prone environments such as the dental root canal. GH12 was described as a potent antimicrobial peptide for oral applications. In the present study, we aimed to evaluate the preclinical relevance of an innovative fibrin hydrogel incorporating antimicrobial peptide GH12 to prevent bacterial contamination of the material during the regeneration process.

Hydrogel's mechanical properties were characterised by rheology and Scanning Electron Microscopy (SEM). GH12 antibacterial effectiveness against Enterococcus faecalis, Porphyromonas gingivalis, and Streptococcus gordonii was determined using Minimum Inhibitory Concentration (MIC) assays as well as inhibition circle assays. Cytocompatibility was assessed through a Live and Dead assay using Dental Pulp Mesenchymal Stem Cells (DP-MSCs) embedded in GH12-fibrin hydrogels.

SEM showed no significant difference in fibre and pore average sizes. MICs were 75 µg/mL for E. faecalis, 4.25 µg/mL for P. gingivalis and 28.15 µg/mL for S. gordonii. GH12 effectively inhibited bacterial growth in both liquid and solid media. DP-MSCs embedded in GH12-fibrin hydrogels (GH12 150 µg/mL) showed a 90 % survival rate at 48 h, compared to fibrin-alone hydrogels.

These results suggest that GH12-fibrin hydrogels might control endodontic infection, as it shows significant antibacterial activity without compromising the hydrogel's structure or cytocompatibility with DP-MSCs. Further studies in vitro and in vivo, are required to optimise GH12 release from the fibrin hydrogel and confirm its safety and effectiveness.