Temporal-controlled Dexamethasone Releasing Chitosan Nanoparticle System Enhances Odontogenic Differentiation of Stem Cells from Apical Papilla

Introduction: The spatial and temporal control of stem cell differentiation into odontoblast-like cells remains one of the major challenges in regenerative endodontic procedures. The current study aims to synthesize and compare the effect of dexamethasone (Dex) release from 2 variants of Dex-loaded chitosan nanoparticles (CSnp) on the odontogenic differentiation of stem cells from apical papilla (SCAP). Methods: Two variants of Dex-loaded CSnp were synthesized by encapsulation (Dex-CSnpl) and adsorption (Dex-CSnpll) methods. The physicochemical characterization of Dex-CSnpl and Dex-CSnpll was assessed by transmission electron microscopy, Zetasizer, and Fourier transform infrared spectroscopy, whereas the Dex release kinetics was assessed by spectrophotometry. A previously characterized SCAP cell line was cultured onto CSnp, Dex-CSnpl, or Dex-CSnpll. The biomineralization potential was determined by alizarin red staining. Alkaline phosphatase, dentin sialophosphoprotein, and dentin matrix protein-1 gene expressions were analyzed by real-time reverse-transcription polymerase chain reaction. Results: Dex-CSnpl resulted in slower release of Dex compared with Dex-CSnpll, but both demonstrated sustained release of Dex for 4 weeks. Biomineralization of SCAP was significantly higher (P < .05) in presence of Dex-CSnpll compared with that in Dex-CSnpl at 3 weeks. Alkaline phosphatase gene expression was significantly higher in the presence of Dex-CSnpll compared with Dex-CSnpl, with peak expression seen at 2 weeks (P < .05). The expression of odontogenic specific marker dentin matrix protein-1 was significantly higher in presence of Dex-CSnpll compared with Dex-CSnpl at 3 weeks (P < .05). Conclusions: Collectively, these data suggest that sustained release of Dex results in enhanced odontogenic differentiation of SCAP. These findings highlight the potential of temporal-controlled delivery of bioactive molecules to direct the spatial- and temporal-controlled odontogenic differentiation of dental stem cells.