Design and Fabrication of Tubular Scaffolds via Direct Writing in a Melt Electrospinning Mode

TLDR

Flexible tubular structures fabricated from solution electrospun fibers are increasingly used in tissue engineering, but controlling fiber deposition is difficult due to the chaotic jet. This study demonstrates melt electrospinning of polycaprolactone in a direct‑writing mode onto a rotating cylinder. By employing non‑conductive polymer melts, the authors achieve predictable fiber deposition and direct‑write onto a rotating cylinder, with fiber winding angle controlling scaffold pore morphology. The resulting tubes, made of 20 µm fibers, exhibit controllable micropatterns and mechanical properties; a finite‑element model predicts that lower winding angles improve tensile and compressive strength, and the tubes support growth of three cell types in vitro, indicating promise for tissue engineering.

Abstract

Flexible tubular structures fabricated from solution electrospun fibers are finding increasing use in tissue engineering applications. However it is difficult to control the deposition of fibers due to the chaotic nature of the solution electrospinning jet. By using non-conductive polymer melts instead of polymer solutions the path and collection of the fiber becomes predictable. In this work we demonstrate the melt electrospinning of polycaprolactone in a direct writing mode onto a rotating cylinder. This allows the design and fabrication of tubes using 20 μm diameter fibers with controllable micropatterns and mechanical properties. A key design parameter is the fiber winding angle, where it allows control over scaffold pore morphology (e.g. size, shape, number and porosity). Furthermore, the establishment of a finite element model as a predictive design tool is validated against mechanical testing results of melt electrospun tubes to show that a lesser winding angle provides improved mechanical response to uniaxial tension and compression. In addition, we show that melt electrospun tubes support the growth of three different cell types in vitro and are therefore promising scaffolds for tissue engineering applications.