Development of Antimicrobial Peptide-loaded Hydrogels as Potential Scaffolds for Pulp-dentine Complex Regeneration: A Comparative Study

Introduction

As a recently developed treatment modality, regeneration of the pulp-dentin-like complex via tissue engineering approaches is the focus of considerable attention. The persistence of bacteria within the root canal spaces is well known as the major challenge of dental pulp regeneration. Antimicrobial peptides (AMPs) are short peptides with inhibitory activities against a broad spectrum of microorganisms.

Methods

In the present study, antimicrobial hydrogels based on 2 photo-reactive biopolymers, that is collagen methacrylate and chitosan methacrylate, and containing 2 different AMPs, that is LLKKK18 and Tet213, were used to develop a potential scaffold with antimicrobial and regenerative features.

Results

The incorporation of AMPs had no significant effect on the physical, mechanical, rheological, and morphological properties of the new systems. The optimized concentration of LLKKK18 and Tet213 had appropriate antimicrobial activity against Gram-positive Enterococcus fæcalis and did not exhibit any cytotoxicity to stem cells from the apical papilla encapsulated within the hydrogels compared to the control group without AMPs. The presence of AMPs also significantly promoted migration and differentiation of stem cells from the apical papilla. In the AMP-loaded groups, greater levels of calcified nodules deposition, alkaline phosphatase, collagen type I, dentin sialophosphoprotein, dentin matrix protein 1, and vascular endothelial growth factor A mRNA gene expression, and collagen type I and dentin sialophosphoprotein protein expression were observed.

Conclusions

The results indicated the potential of engineered antimicrobial collagen methacrylate/chitosan methacrylate hydrogels for application in tissue engineering-based strategies to regenerate the pulp-dentin complex.