Bioactive photo-crosslinkable hydrogel based on decellularized dental pulp matrix for functional pulp regeneration

Dental pulp extracellular matrix (DPEM), as a naturally derived scaffold material for dental pulp regeneration, exhibits excellent biocompatibility. This study aims to develop a novel photo-cross-linked hydrogel composed of methacry- lated gelatin (GelMA) loaded with DPEM for application in pulp regeneration. In vitro experiments demonstrated that the GelMA–DPEM hydrogel, fabricated by mixing a 10 mg mL − 1 DPEM solution with a 10% (w/v) GelMA solution at a ratio of 1:1, formed a stable cross-linked network with a swelling ratio of approx- imately 343%. Frequency-sweep rheology indicated that incorporation of DPEM increased the storage modulus of the hydrogel compared with GelMA alone, and the composite hydrogel significantly promoted cell migration and angiogenic ca- pacity. RT–qPCR analysis revealed that the GelMA–DPEM hydrogel markedly upregulated the expression levels of neuroepithelial stem cell protein (Nestin), dentin sialophosphoprotein (DSPP), platelet endothelial cell adhesion molecule-1 (CD31), and runt-related transcription factor 2 (Runx2). Moreover, ectopic trans- plantation in nude mice indicated that, when combined with human dental pulp stem cells (hDPSCs), the GelMA–DPEM hydrogel preserved the DPEM’s capa- bility to support the formation of a cell-rich, vascularized pulp-like tissue con- sisting of collagen-rich connective tissue and CD31-positive blood vessels. In conclusion, the GelMA–DPEM hydrogel showed favorable cytocompatibility and preliminary pro-angiogenic effects in vitro and supported pulp-like tissue forma- tion in a small-animal ectopic treated dentin matrix (TDM) model. These findings suggest that GelMA–DPEM is a promising candidate scaffold for dental pulp re- generation.