Synergistic regulation of hDPSC-iPSCs by tetrahedral DNA nanostructures for dentin-pulp complex regeneration

The regeneration of a functional dentin-pulp complex represents a paramount objective in regenerative endodontics. However, current strategies reliant on scaffolds and growth factors are constrained by imprecise biological signaling and inefficient stem cell guidance. To address these limitations, this study aimed to develop a precise nanomaterial-based strategy. We investigated tetrahedral DNA nanostructures (TDNs) as bioactive nanocarriers to enhance the odontogenic differentiation of human dental pulp stem cell-derived induced pluripotent stem cells (hDPSC-iPSCs) within a gelatin methacryloyl (GelMA) hydrogel system. hDPSCs were isolated from young patients' teeth, reprogrammed into iPSCs, and characterized. TDNs were synthesized, characterized, and shown to be efficiently internalized by cells. In vitro, TDN treatment significantly upregulated key odontogenic markers (DSPP and DMP-1), promoted proliferation, and enhanced migration of hDPSC-iPSCs. For in vivo assessment, TDN-pretreated hDPSC-iPSCs encapsulated in GelMA were implanted into a tooth root canal regeneration model in nude mice. The TDN group regenerated well-structured, dentin-pulp-like tissues exhibiting strong dentin sialophosphoprotein (DSPP) expression, indicative of odontogenic differentiation. Collectively, these findings demonstrate that TDNs potently direct hDPSC-iPSCs toward an odontogenic lineage and support pulp-like tissue formation within a hydrogel niche. The integrated TDN-cell-GelMA platform presents a novel, precise, and minimally invasive strategy for early-stage pulp-like regeneration, with promising potential for clinical translation in regenerative endodontics.