Bioengineered Gelatin Hydrogels Functionalized with VEGF/BMP2 Mimetic Peptides for Advancing Regenerative Endodontics

Regenerating the pulp-dentin complex is challenging due to its distinct biological, anatomical, and mechanical properties. To address this, we explored gelatin-based hydrogels modified by covalently binding vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP2) mimetic peptides to target pulp and dentin regeneration.

Three distinct hydrogels: GelMA (gelatin methacrylate, 5% w/v), GelNB (norbornene-modified gelatin, 5% w/v), and GelMN (5% GelMA: 5% GelNB = 1:1) were prepared and characterized by scanning electron microscopy (SEM, n = 3), Fourier transform infrared spectroscopy (FTIR, n = 3), and swelling ratio analysis (n = 3). Human dental pulp stem cells (DPSCs) were encapsulated to assess viability (live/dead staining, n = 3) and spreading (n = 3). DPSCs and human umbilical vein endothelial cells were cocultured in a VEGF mimetic peptide (200 μg/ml) functionalized GelMN hydrogel to evaluate vascular structure formation (n = 3). Conversely, DPSCs were encapsulated in a BMP2 mimetic peptide (20 μM) functionalized GelMA hydrogel to investigate the odontogenic differentiation (n = 3).

SEM analysis showed GelMA exhibited a denser, more tightly crosslinked network and smaller pore size compared to GelNB/GelMN. FTIR confirmed the chemical composition of all 3 hydrogels, and the swelling ratio demonstrated no significant difference among them. All hydrogels exhibited excellent biocompatibility and supported cell viability after culturing with DPSCs. VEGF mimetic peptide in GelMN enhanced vascular tube formation by human umbilical vein endothelial cells supported by DPSCs. In parallel, BMP2 mimetic peptide in GelMA significantly boosted the odonto-/osteogenic differentiation of DPSCs, as indicated by the expression of dentin sialophosphoprotein, alkaline phosphatase, and mineralization levels.

VEGF and BMP2 mimetic peptide-functionalized gelatin hydrogels is a promising approach to enhance pulp-dentin complex regeneration.