Boosting Functional Dental Pulp Regeneration by a Biomimetic Self-assembling Hydrogel through Remodeling the Stem Cell Niche

Cell-free strategies for dental pulp regeneration rely on the recruitment of endogenous stem cells, but cell entry alone is not sufficient. The stem cells require staged niche cues that support early mechanical adaptation and later coordinate odontogenic, angiogenic, and neural supportive responses. Here, we report RQK (RADA16/QP5/KLT), an injectable self-assembling peptide hydrogel designed to integrate extracellular matrix-like architecture with instructive bioactive cues for functional pulp regeneration. RQK combines the RADA16 (RAD) nanofibrous backbone with the amelogenin-derived odontogenic motif QP5 and the vascular endothelial growth factor (VEGF)-mimetic angiogenic motif KLT. The hydrogel formed at 37°C, showed injectability and recovery, and could adapt to the irregular root canal space. In three-dimensional culture, RQK guided human dental pulp stem cells through a staged regenerative response. RQK first maintained stemness and mechanosensitive signaling, then promoted adhesion remodeling, odontogenic differentiation, enhanced angiogenic activity, and neural supportive effects. Transcriptomic analysis further linked this staged response to extracellular matrix interaction, cell adhesion, mechanosensitive signaling, and developmental programs. Molecular dynamics simulations and ultrastructural analyses suggested that interactions between RQK and collagen created a matrix environment favorable for odontogenic differentiation. Furthermore, evaluations across different stages in an infected immature beagle tooth model revealed that RQK promoted periapical healing and continued root development. Newly formed pulp-like tissue was more functional and showed odontoblast-like cell arrangement, vascular ingrowth, and neural tissue formation. These findings demonstrate that biomimetic niche reconstruction can guide endogenous stem cell behavior and improve cell-free dental pulp regeneration in vivo, providing a biomimetic framework for enhancing in situ tissue regeneration. STATEMENT OF SIGNIFICANCE: This research developed RQK, an injectable self-assembling peptide hydrogel for cell-free dental pulp regeneration. Unlike conventional scaffold designs, RQK combines a nanofibrous matrix that mimics the extracellular matrix with odontogenic and angiogenic bioactive motifs. The hydrogel forms at 37°C, adapts to the irregular root canal space, and guides endogenous stem cell behavior through staged niche cues. It supports early mechanical adaptation, later odontogenic differentiation, angiogenic activity, and neural supportive effects. In an infected immature beagle tooth model, RQK promoted periapical healing, continued root development, and organized pulp-like tissue formation, providing a biomimetic strategy for enhancing in situ tissue regeneration.