Hierarchically decorated electrospun poly( $$ \varepsilon $$ ε -caprolactone)/nanohydroxyapatite composite nanofibers for bone tissue engineering

Bone is a nanocomposite comprised of two main components, nanohydroxyapatite (nHA) and Type I collagen. The aim of this study is to mimic the nanotopography of collagen fibrils in bone tissue and to modulate their cellular functions by nanoscale stimulation. Three-dimensional structures consisting of electrospun poly( $$ \varepsilon $$ -caprolactone) (PCL) and PCL/nHA composite nanofibers decorated by periodically spaced PCL crystal lamellae (shish–kebab structure) were created. It was found that the hierarchically decorated nanostructure not only enhanced the mechanical properties of the scaffolds but also changed the surface wettability behavior of the scaffolds. The enhanced surface wettability facilitated biomimetic mineralization through apatite deposition when exposed to simulated body fluids (SBF). MG-63, an osteosarcoma cell line which behaves similarly to osteoblasts, was used to study the cellular response to the scaffolds. Data suggest kebab crystal nanotopography facilitating cell attachment and proliferation. Functional assays, which quantify alkaline phosphatase (ALP) and calcium expression, revealed increased ALP activity and increased calcium expression on decorated nanofibers. In addition, compared with other scaffolds, the cells on PCL/nHA nanofibrous shish–kebab-structured scaffolds showed obvious extended pseudopodia of the filaments in the cytoskeleton study, demonstrating better interactions between cells and scaffolds.