Annika Hangleiter (Garching, DE), Kilian Arthur Maria Mueller (Garching, DE), Sarah Burkhardt (Garching, DE), Diana Marcela Rojas-González (Garching, DE), Christina Kwade (Garching, DE), Sebastian Tobias Pammer (München, DE), Dr. Stefan Leonhardt (München, DE), Prof. Dr. Petra Mela (Garching, DE)
Abstract text (incl. figure legends and references)
Introduction: Melt electrowriting (MEW) is a promising electric field-assisted biofabrication strategy for complex 3D scaffolds. However, to date, conventional MEW provides the polymer melt in a syringe and relies on highly specialized machine technology, which restricts MEW accessibility to a wider user group.
Objectives: The aim is to exploit the widely used Fused Filament Fabrication (FFF) technology by retrofitting low-cost FFF systems to enable electrohydrodynamically-driven microfiber deposition.
Materials & Methods: We modified a FFF printer to apply a high-voltage electric field between the nozzle tip and the printing bed, by grounding the nozzle and introducing an in-house developed collector. Customized Gcodes were programmed in an Excel spreadsheet. Scaffold morphologies were evaluated via scanning electron microscopy (SEM) and mechanical testing. Human umbilical vein endothelial cells (HUVECs) were cultured on scaffolds for three days.
Results: The upgrade enabled filament-based MEW (F-MEW), as validated with the MEW gold standard material polycaprolactone (PCL). We controlled fiber diameters ranging from 33.8 ± 1.4 down to 10.7 ± 0.5 μm in linear (box pores) and non-linear patterns. The melt-on-demand concept of F-MEW enabled - for the first time - direct writing of the thermo-sensitive polymer polydioxanone (PDO). HUVECs adhered and proliferated on the F-MEW microfibers. Ultimately, we hybridized the FFF with the F-MEW mode of the system to fabricate multiscale constructs both from PCL and PDO.
Conclusion: This work presents a filament-based approach to MEW by building on the FFF technology ecosystem. F-MEW holds great potential to introduce electrohydrodynamic writing of polymer melts to a much wider user group and can now be easily implemented into existing FFF machines. Furthermore, combining F-MEW with FFF in the same machine brings unprecedented capabilities for multiscale additive manufacturing, de facto expanding the FFF fabrication window.