Fabrication of hierarchical polycaprolactone/gel scaffolds via combined 3D bioprinting and electrospinning for tissue engineering

It is a severe challenge to construct 3D scaffolds which hold controllable pore structure and similar morphology of the natural extracellular matrix (ECM). In this study, a compound technology is proposed by combining the 3D bioprinting and electrospinning process to fabricate 3D scaffolds, which are composed by orthogonal array gel microfibers in a grid-like arrangement and intercalated by a nonwoven structure with randomly distributed polycaprolactone (PCL) nanofibers. Human adipose-derived stem cells (hASCs) are seeded on the hierarchical scaffold and cultured 21 d for in vitro study. The results of cells culturing show that the microfibers structure with controlled pores can allow the easy entrance of cells and the efficient diffusion of nutrients, and the nanofiber webs layered in the scaffold can significantly improve initial cell attachment and proliferation. The present work demonstrates that the hierarchical PCL/gel scaffolds consisting of controllable 3D architecture with interconnected pores and biomimetic nanofiber structures resembling the ECM can be designed and fabricated by the combination of 3D bioprinting and electrospinning to improve biological performance in tissue engineering applications.