Exploiting Nonlinear Fiber Patterning to Control Tubular Scaffold Mechanical Behavior

Melt electrowriting is an additive manufacturing technique capable of fabricating highly biomimetic polymer scaffolds with high-resolution microarchitecture for a range of tissue engineering applications. The use of a rotating mandrel to fabricate tubular scaffolds using this technique is increasing in popularity; however, the translation of many novel scaffold designs that have been explored on flat collectors has yet to be realized using mandrels. This study reports novel tools to automatically generate scaffold gcode for several new tubular scaffold designs, investigating a range of auxetic pore geometries and open unit cell designs. Through optimization of printing parameters, the novel scaffold designs are successfully printed and mechanically tested to assess tensile properties. Open unit cells significantly reduce the tensile stiffness of scaffolds manufactured with closed pores. Auxetic scaffolds could also be widely tuned using the novel gcode generator tool to exhibit similar stress–strain profiles to typical crosshatch scaffolds but could be made to expand to desired radial dimensions. Finally, heterogeneous auxetic constructs are also fabricated with regions of various radial compliances. This study presents several, mechanically validated novel scaffold designs that are of interest for future applications in targeted tissue engineering product development as well as in soft robotic actuation.