A nano-micro alternating multilayer scaffold loading with rBMSCs and BMP-2 for bone tissue engineering.

In this study, we develop a nano-micro alternating multilayer scaffold for bone tissue engineering by incorporation of monodispersed calcium alginate microbeads into electrospun polymer nanofibers. Both rat bone marrow mesenchymal stem cells (rBMSCs) and bone morphogenetic protein-2 (BMP-2) are simultaneously loaded into the microbeads, which are generated from a microfluidic device. The layer number of the scaffold can be readily controlled by alternately repeating the electrospinning and the microfluidic processes. Alkaline phosphatase (ALP) activity and Alizarin Red S staining results demonstrate that this rBMSCs and BMP-2 loaded nano-micro alternating multilayer scaffold presents an outstanding osteogenic effect in vitro. Histological and immunohistochemical assessments further reveal that this multilayer scaffold has a significant capability of ectopic bone formation in vivo, enabling this newly developed scaffold to be suitable for wide applications in tissue engineering.