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

Abstract

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 macroporous 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.