Osteogenic Efficacy of Porous Glass Microspheres-Loaded Dental Pulp Stem Cell-Derived Exosomes for Orthobiologic...

The appropriate characteristics of carrier biomaterial must prevent rapid sequestration and clearance of exosomes. This study aims to investigate the efficacy of porous phosphate-based glass microspheres (PGMS) as carriers for human dental pulp stem cell (hDPSC)-derived exosomes in dental orthobiologic applications. PGMS (40P₂O₅-24MgO-16CaO-20Na₂O) is prepared via flame spheroidization, characterized using SEM-EDS, XRD, and mercury intrusion porosimetry. hDPSC-Exosomes (Exo) are extracted, labeled with DiL, and verified by confocal and flow cytometry. Cell viability is assessed whereby hDPSCs are exposed to 1 mg/mL PGMS, or 10 µg/mL Exo, or 1 mg/mL PGMS loaded with 10 µg/mL Exo. Osteogenic potential is assessed by ALP assay, qPCR, western blotting, and alizarin staining. PGMS exhibits 75% interconnected pores, and XRD shows broad halo peak within the 2θ range of 20°-40°. Exo are CD9⁺, CD63⁺, and CD81^+, and their cellular uptake is enhanced by 24 h. PGMS supports continued hDPSC proliferation. Exo-alone boosts hDPSC proliferation (24 h) and PGMS+Exo shows a similar rise. Exo-alone and PGMS+Exo significantly upregulate bone markers, while PGMS+Exo significantly upregulates Col1, ALP, and increases nodule formation. Western blotting shows an increase in BMP7, Col1, and OC in Exo-alone and PGMS+Exo. PGMS retains Exo, protects its functionality and release for favorable osteogenesis, offering a promising strategy as an exosome carrier in orthobiologic applications.