Novel Extrusion Based Co-axial Printing Head for Tissue Engineering

Abstract

Additive manufacturing (AM) is a key technology for the fabrication of tissue engineering scaffolds, 3D structures that support cell attachment, proliferation, and differentiation. However, commercially available printing heads for tissue engineering applications present limitations concerning the fabrication of complex multi-material hierarchical structures resembling natural tissues. This paper presents a novel printing head assembled with a new designed co-axial nozzle that aims to generate core-shell filaments. Compared to commercially available co-axial extruders, which usually use needle-based nozzles and can only process liquid materials, the novel co-axial printing head is able to process both low-viscosity and high-viscosity materials. Two independent extruding systems that can be replaced by screw-based or pressure-based extruders are assembled on the co-axial nozzle allowing different type of materials to be processed. An expanding chamber is placed at the cross section of the inner and outer channel to achieve a symmetrical velocity distribution. Simulation results demonstrate that the novel co-axial nozzle allows a balanced fluid flow enabling uniform co-axial filaments.