OR21 - Orchestrating Angiogenesis in Regenerative Endodontics Using a Hydrogel Embedded with VEGF-mimetic Aptamer and Roxadustat-loaded Theranostic Nanoparticle

Abstract: Regenerative endodontics aims to restore the dental-pulp complex; however, achieving angiogenesis remains a challenge. Hydrogels have gained attention as safe, injectable biomaterials for drug delivery and tissue growth within the pulp space. This study evaluated the extracellular proangiogenic action of aptamer (Apt02) and intracellular effect of roxadustat-conjugated (FG-4592) smart nanoparticle as collagen hydrogel constituents. Carbon quantum dots (CQD) were synthesized to create core-shell silica nanoparticles (CQD@MSN-NH2). Subsequently, FG-4592 was cross-linked onto CQD@MSN-NH2 using human serum albumin linker to fabricate CQD@MSN-HSA-FG (CMHF). Extensive characterization techniques were employed to determine physicochemical characteristics of CMHF. Biocompatibility of CMHF was assessed across different cell lines. Western blot and quantitative PCR (qPCR) were utilized to elucidate the different mechanisms of action of Apt02 and CMHF. CMHF characterization revealed nanoparticles averaging 220 nm in diameter, featuring central CQD fluorophore and porous silica shell with 9.94 wt% FG-4592 loading capacity. Apt02 and CMHF demonstrated compatibility across various cell lines. Western blot and qPCR confirmed Apt02 and CMHF were proangiogenic with extracellular and intracellular mechanisms, respectively. CMHF showed no interference with adhesion, entered human periodontal ligament fibroblasts within three hours and released FG-4592 in response to cellular protease. Individually, 1 µM Apt02, 20 µM FG-4592, and 0.01 mg/mL CMHF induced human umbilical vein endothelial cell tube formation, with VEGF as control. Additionally, collagen hydrogel containing Apt02 and CMHF synergistically promoted new vessel formation in chorioallantoic membrane assay, using VEGF for comparison. Apt02 and CMHF embedded hydrogel is proangiogenic and may be considered for endodontic regeneration.