A Multi-functional st-ELR Scaffold for Dentin Regeneration

Abstract

Pulpitis is one of the most widespread diseases in the world. Current advances in dental tissue engineering have provided an interesting alternative therapeutic approach in the field of regenerative endodontics. However, there remains a strong need to develop an optimized scaffold for supporting dentin regeneration. The objective of this PhD project is to develop a dental scaffold using elastin-like recombinamers(ELRs) to stimulate dentin regeneration while exhibiting antimicrobial ability to control potential re-infection of the pulp cavity. To provide a biomimetic scaffold that resembles the extracellular matrix in dentin tissue, we fabricated fibrous scaffold of ELRs using electrospinning technique and analyzed its ability in inducing biomimetic mineralization using the polymer-induced liquid precursor (PILP) process. The ELR scaffolds exhibited intra- and extra-fibrous mineralization, which highly mimicked the structure of mineralized native collagen in dentin. The scaffold is expected to be applied in the pulp cavity with direct contact with the pulp tissue. Therefore, we investigated the interaction between the mineralized ELR scaffold that contains statherin-derived peptide (st-ELR) and human dental pulp stem cells (hDPSCs). Proliferation and odontogenic differentiation of hDPSCs were analyzed and the study indicated that biomimetically mineralized st-ELR scaffold supported the proliferation and odontogenic differentiation of hDPSCs. Bacterial infection is considered as the major reason for the failure of implanted materials. Therefore, we functionalized st-ELR scaffold with antimicrobial peptides to prevent the potential infection caused by oral bacteria. A cysteine modified antimicrobial peptide GL13K(Cys-GL13K) was used in this study to achieve site-specific modification on the developed scaffold. First, we tethered Cys-GL13K peptides on titanium surface to analyze the properties and antimicrobial ability of immobilized peptides. A homogenous and strong coating of peptides was obtained. The tethered peptides exhibited promising antimicrobial ability against S. mutans, S. gordonii and E. faecalis. Furthermore, we bio-conjugated the peptides to st-ELR membranes using the same modification technique. Successful peptide modification was achieved, and the peptide functionalized st-ELR membrane exerted antimicrobial ability against S. mutans and S. gordonii. This research sheds light on the development and functionalization of scaffolds for the application of regenerating hard tissues such as dentin and bone. It allows the scaffold to highly resemble the architecture and physical properties of extracellular matrix in mineralized tissues. In addition, this research provides a new approach to modify the scaffold with diverse bioactive molecules to obtain multiple functions, while maintaining good interaction with native tissues.