Tissue engineering at the dentin-pulp interface using human treated dentin scaffolds conditioned with DMP1 or BMP2 plasmid DNA-carrying calcium phosphate nanoparticles

Hard dental tissue pathologies, such as caries, are conventionally managed through replacement by tooth -colored inert biomaterials. Tissue engineering provides novel treatment approaches to regenerate lost dental tissues based on bioactive materials and/or signaling molecules. While regeneration in the form of reparative dentin (osteo-dentin) is feasible, the recapitulation of the tubular microstructure of ortho-dentin and its special features is sidelined. This study characterized in vitro , and in vivo human EDTA-treated, freeze-dried dentin matrices (HTFD scaffolds) conditioned with calcium phosphate nanoparticles (NPs) bearing plasmids encoding dentinogenesis-inducing factors (pBMP2/NPs or pDMP1/NPs). The up-take and transfection efficiency of the synthesized NPs on dental pulp stem cells (DPSCs) increased in a concentration-and time-dependent manner, as evaluated qualitatively by confocal laser microscopy and transmission electron microscopy, and quantitatively by flow cytometry, while, in parallel, cell viabil-ity decreased. HTFD scaffolds conditioned with the optimal transfectability-to-viability concentration at 4 lig Ca/mL of each of the pBMP2/NPs or pDMP1/NPs preserved high levels of cell viability, evidenced by live/dead staining in vitro and caused no adverse reactions after implantation on C57BL6 mice in vivo . HTFD/NPs constructs induced rapid and pronounced odontogenic shift of the DPSCs, as evidenced by relevant gene expression patterns of RunX2, ALP, BGLAP, BMP-2, DMP-1, DSPP by real-time PCR, and acquirement of polarized meta-mitotic phenotype with cellular protrusions entering the dentinal tubules as visualized by scanning electron microscopy. Taken together, HTFD/NPs constitute a promising tool for customized reconstruction of the ortho-dentin/odontoblastic layer barrier and preservation of pulp vital-ity.(c) 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Tissue engineering provides new treatment approaches for regenerating lost dental tissues, and this study investigated the characteristics of EDTA-treated, freeze-dried dentin matrices (HTFD scaffolds) conditioned with calcium phosphate nanoparticles (NPs) bearing dentinogenesis-inducing factors. The synthesized NPs showed efficient transfection of dental pulp stem cells (DPSCs), and HTFD/NPs constructs induced odontogenic shift of DPSCs, preserving cell viability and leading to the reconstruction of the ortho-dentin/odontoblastic layer barrier.