Engineering Porosity in Electrospun Nanofiber Sheets by Laser Engraving: A Strategy to Fabricate 3D Scaffolds for Bone Graft Applications

Nanofiber features in a scaffold provide favorable niche for cellular attachment, proliferation, and differentiation propelling their interest in tissue engineering. However, the inability of seeded cells to infiltrate inside 3D structures of electrospun nanofibers has remained a persistent bottleneck for their greater applicability. In the present work, an approach to address this problem is presented. Macro-pores are designed in common graphic software created by a laser-engraving machine on electrospun nanofiber sheets composed of a bioinspired material-N-methylene phosphonic chitosan for facilitating cellular infiltration into 3D scaffold. Effect of laser pulse energy and pulse per inch on pore morphology are investigated and FTIR spectrum is examined to preclude the degradation of material due to laser-engraving process. Furthermore, the micro-fabricated nanofiber sheets with multi-scalar porosity are rolled up to form a 3D scaffold as graft through biomimetic approach for bone-tissue engineering applications. Culture of MG-63 cells on rolled up nanofiber sheets containing laser-engraved macro-porous 3D scaffolds demonstrated no cytotoxicity induced by the scaffolds from MTT assay, while cellular migration into the sheets was evident from scanning electron microscopy. It is concluded that combined micro-fabrication-rolling approach may be simple, rapid way to design 3D bone grafts based on 2D electrospun nanofiber sheet of natural/semi-synthetic polymers for better osteoconductivity.