In the process of bone tissue regeneration, regulation of osteogenesis-angiogenesis coupling is of great importance. Therefore, dimethyloxallyl glycine (DMOG) is loaded by nanoscale zeolitic imidazolate frameworks-8 (ZIF-8) to obtain a drug-loading system that can promote osteogenesis-angiogenesis coupling. Characterization of the drug-loading nanoparticles (DMOG@ZIF-8) reveals that DMOG is successfully loaded into ZIF-8 by two different methods, and the DMOG@ZIF-8 is prepared using the one-pot method (OD@ZIF-8) achieves higher loading efficiency and longer release time than those prepared using the post-loading method (PD@ZIF-8). In vitro studies found that DMOG@ZIF-8 significantly enhances the migration, tube formation, and angiogenesis-related protein secretion of human umbilical vein endothelial cells as well as the extracellular matrix mineralization, alkaline phosphatase activity, and osteogenesis-related protein secretion of bone marrow mesenchymal stem cells. Moreover, OD@ZIF-8 nanoparticles are more efficient than PD@ZIF-8 nanoparticles in induction of osteogenesis-angiogenesis coupling. Then, in vivo cranial critical defect model shows that the addition of OD@ZIF-8 significantly promotes vascularized bone formation as indicated by the results including microcomputed tomographic, histological and immunofluorescence staining, and so on. Taken together, loading ZIF-8 with DMOG may be a promising solution for critical-sized bone defect reconstruction and the one-pot method is preferred in the preparation of such drug-loading system.
Keywords: bone regeneration; dimethyloxallyl glycine; drug loading; vascularization; zeolitic imidazolate frameworks-8.
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