Abstract:Bioprinting is a layer-by-layer additive fabrication technique for making three-dimensional (3D) tissue and organ constructs using biological products. The capability to fabricate 3D tubular structure in free-form or vertical configuration is the first step towards the possibility of organ printing in three dimensions. In this study, alginate-based tubular structures of varying viscosity were printed vertically using multi-nozzle extrusion-based technique. Manufacturing challenges associated with the vertical printing configurations are also discussed here. We have also proposed measurable parameters to quantify the quality of printing for systematic investigation in bioprinting. This study lays a foundation for the successful fabrication of viable 3D tubular constructs. Keywords: 3D printing, alginate, viscosity, rapid prototyping, additive manufacturing, extrusion