Abstract:Genetic modification of biological scaffold to enhance angiogenesis is an effective method for bone regeneration. In this study, a 3D-PLGA/nHAp scaffold containing pdgfb-expressing lentiviral vectors to enhance angiogenesis for calvarial critical bone defect repair was designed. The modified scaffolds (LVpdgfb/ PLGA/nHAp) could continuously release bioactive LV-pdgfb particles for up to 5 days in vitro. In scaffold implanted critical calvarial bone defect mouse model, how the genetically modified 3D scaffolds affect the angiogenesis and bone formation was studied by two-photon and photoacoustic imaging, microCT and histomophological methods. Eight weeks post-implantation, blood vessel areas in LV-pdgfb/PLGA/nHAp scaffolds were significantly higher than in PLGA/nHAp scaffolds at each observed time point. In accordance with the angiogenesis process, microCT analysis indicated that the repairment of the critical-calvarial defects in LV-pdgfb/PLGA/nHAp group dramatically improved compared to the other groups, including bone mineral density (BMD), the ratio of bone volume to tissue volume (BV/TV), trabecular number (Tb.N). In this study, we verified and compared the application of two state of the art non-invasive in vivo imaging techniques in imaging of neo-vasculature inducing in 3D bone artifact, and demonstrated that lentivirus-mediated pdgf-b gene modified scaffolds could be a promising tool to build vascularized tissue engineering bone to repair a large bone defects in murine model.