Development of three-dimensional scaffolds containing electrospun nanofibers and their applications to tissue regeneration

Abstract

In recent years, several studies have attempted to produce scaffolds with various structural properties using micro-fabrication techniques based on Rapid Prototyping (RP) methods. The first step in this research is the fabrication of bio-applicable three-dimensional (3D) structures to tissue engineering scaffolds. The developed process, namely direct polymer melt deposition (DPMD) process, employs a micropositioning system equipped with a pressure-activated micro syringe and heating module for extruding and depositing the polymer melts. Through this process, highly-controllable regular 3D structures can be successfully manufactured. Under various process conditions including temperature, pneumatic pressure and moving velocity of a nozzle, the controllability of the developed 3D structures was verified. The resultant scaffold can satisfy the requirements of structural properties such as macroscopic external shapes, internal architectures, porosity and pore size. For the practical and bio-functional applications to tissue engineering, surface modification with bioactive agents was performed so that the limited properties for cell adhesion due to smooth surface and hydrophobicity of the developed scaffold can be overcome. On the other hand, some researchers have recognized the importance of nano-structured architecture in view of biological applications; thus, they have aimed to produce functionalized scaffolds that can mimic the nanofibrous structure of the natural extracellular matrix (ECM) and tried to fabricate various nano- and micro- scaled structures to enhance cell activation. Meanwhile, the current interest in the electrospinning methods has been concentrated on other forms of nanofibers, especially uniaxially oriented arrays of nanofibers, in order to expand their tissue engineering applications. For the fabrication of nanostructured scaffolds, the general electrospinning method and the proposed fiber alignment technique are employed. Especially, as the...