The effect of modified electrospun PCL-nHA-nZnO scaffolds on osteogenesis and angiogenesis

Large bone defects treatment is one of the challenges in current bone tissue engineering approaches. Various strategies have been proposed to address this issue, among which, prevascularization by coculturing of angiogenic and osteogenic cells on the scaffolds can alleviate this problem. In the present study, modified fibrous scaffolds were prepared by electrospinning and subsequent ultrasonication of polycaprolactone (PCL) containing nano-hydroxyapatite (n-HA), with/without nano-zinc oxide (n-ZnO), and polyethylene oxide [PEO] as a sacrificial agent. The physical, mechanical, and chemical characteristics of the scaffolds were evaluated. The results showed the presence of n-ZnO, which in turn increased Young's module of the scaffolds from 5.5 ± 0.67 to 6.7 ± 1.77 MPa. Moreover, MTT, SEM, alkaline phosphatase (ALP) activity, chicken embryo chorioallantoic membrane (CAM) assay, and real-time RT-PCR were utilized to investigate the biocompatibility, cell adhesion and infiltration, osteoconductivity, angiogenic properties, and expression of osteogenic and angiogenic related genes. ALP assay showed that the highest enzyme activity was noted when the modified scaffolds containing n-ZnO were seeded with HUVEC:hBMSC at the cell ratio of 1:5. CAM assay showed induction of angiogenesis for the scaffolds containing n-ZnO. Real-time RT-PCR results showed significant upregulation of angiogenic related genes. Thus, the scaffolds containing n-ZnO may have great potential for osteogenesis and angiogenesis in tissue engineering applications.