Nanocomposite scaffolds incorporating ginsenoside Rg1-loaded ZIF-8 nanoparticles for enhanced osteogenesis and bone regeneration

BACKGROUND: Current bone tissue engineering scaffolds face challenges such as inadequate mechanical support, limited biocompatibility, and suboptimal osteogenesis for treating critical-sized bone defects. This study introduces a novel collagen/silk fibroin/carboxymethyl cellulose (CMC) scaffold integrated with ginsenoside Rg1-loaded Zeolitic Imidazolate Framework-8 (ZIF-8) nanoparticles (GINZIF-8), engineered to enhance the scaffold’s osteoinductive capacity and overall regenerative performance. METHODS: Nanocomposite scaffolds were fabricated by incorporating ginsenoside Rg1–loaded ZIF-8nanoparticles into collagen/silk fibroin/ CMC matrices and processed via freeze-drying and glutaraldehyde crosslinking. Scaffold physicochemical properties, in vitro osteogenic responses of bone marrow–derived mesenchymal stem cells (BMMSCs), and in vivo bone regeneration in a rat critical-sized calvarial defect model were evaluated, with systemic safety analysis performed by liver histology and serum biochemical analyses. RESULTS: The constructs were fabricated to feature a fibrous, porous structure conducive to cell infiltration and nutrient diffusion. ZIF-8 nanoparticles were incorporated into the scaffold matrix, with successful encapsulation of ginsenoside Rg1 verified by Fourier Transform Infrared Spectroscopy (FTIR) analysis. The optimal formulation of the composite scaffolds (scaffolds loaded with 2 w/w% GINZIF-8) demonstrated improved mechanical properties (2.69 ± 0.14 MPa), and controlled ginsenoside Rg1 release (44.66 ± 7.84% over 7 days). In vitro assays confirmed that the GINZIF-8 nanoparticles significantly enhanced osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs) potentially through activation of the Bone Morphogenetic Protein-2/SMAD signaling pathway. Additionally, the scaffolds exhibited antioxidant and anti-inflammatory effects, reducing oxidative stress and pro-inflammatory cytokine levels. In vivo studies revealed that the collagen/silk fibroin/CMC scaffolds loaded with 2 w/w% GINZIF-8 nanoparticles promoted substantial new bone formation (42.59 ± 3.70%) in a critical-sized defect model in rats, surpassing the performance of control scaffolds. Enhanced bone healing was attributed to the scaffold’s ability to support osteogenic differentiation, reduce oxidative stress, and modulate inflammation, with activation of the Phosphatidylinositol 3-Kinase/Protein Kinase B (PI3K/AKT) signaling pathway and inhibition of Glycogen Synthase Kinase-3 Beta (GSK3β) contributing to improved osteogenesis. CONCLUSION: These results demonstrate that Rg1-loaded ZIF-8 nanocomposite scaffolds effectively enhance BMMSC osteogenic differentiation and promote robust bone regeneration in vivo, while exhibiting excellent biocompatibility and systemic safety. Overall, the developed scaffolds represent a promising strategy for advanced bone tissue engineering applications.