Chitosan-Based miR-675 Nanocarriers Immobilized on Polycaprolactone/Silk Fibroin Nanofibers for Enhanced Odontogenic Differentiation

Enhancing odontogenic differentiation of dental pulp stem cells (DPSCs) is a crucial aspect of regenerative endodontic treatments. Herein, miR-675-loaded chitosan nanoparticles were engineered to obtain ultra-small, positively charged complexes (~60 nm, zeta potential > +15 mV) with high colloidal stability, biocompatibility, and 70% cellular uptake. These nanocarriers were immobilized onto polydopamine-modified PCL/silk fibroin nanofibers, using pH-controlled deposition to tune chitosan protonation, nanoparticle aggregation, and surface coverage without disrupting the three-dimensional fibrous architecture. This approach produced a uniform miR-675/CSNPs-loaded PD-modified PCL/SF scaffold with increased hydrophilicity and preserved interconnected porosity, thereby enhancing DPSC adhesion, proliferation, and cytoskeletal organization compared with bare scaffolds. Moreover, alkaline phosphatase activity, extracellular matrix mineralization, and Western blot analysis revealed marked upregulation of odontogenic markers, including RUNX2, ALP, COL-I, DSPP, and DMP-1. Collectively, these findings demonstrate a synergistic effect between sustained miR-675 delivery via CSNPs and the biomimetic PCL/SF architecture, establishing a promising platform for odontogenic differentiation of DPSCs and dentin-pulp complex regeneration.