Cell-derived Extracellular Matrix Proteins in Colloidal Microgel as a Self-Assembly Hydrogel for Regenerative Endodontics

This study investigated a colloidal microgel for angiogenic and odontogenic differentiation of cells in the presence of cell-derived extracellular matrix (ECM) proteins using a 3-dimensional culture model. Viscoelastic properties of human dental pulp were determined to understand the native ECM environment. ECM proteins were extracted from dental pulp stem cell (DPSC) cultures, and MaxGel (Millipore Sigma, Burlington, MA) was used as a commercially available ECM protein. DPSCs were incubated in colloidal microgels in the presence of ECM proteins or gelatin methacryloyl (GelMA) as a bulk hydrogel (n = 9/group). The viability and odontogenic differentiation of DPSCs within hydrogels was determined using viability assays, mineralization staining, calcium and alkaline phosphatase assays, and quantitative polymerase chain reaction for odontogenic gene expression. Angiogenic properties of endothelial cells were determined using tubule formation assays and quantitative polymerase chain reaction to detect angiogenic gene expression. Dental pulp had a higher elastic modulus than the viscous modulus, showing a solidlike response similar to hydrogels. DPSC-derived ECM showed higher collagen and GAG than MaxGel (P