A) A schematic depiction of the coaxial printing process fabrication process. Alginate gelation is realized in coaxial printing (i), thermal crosslinking of collagen fibers is then induced by incubation at 37 °C (ii), followed by immersion in medium to the and obtain a hollow tubular shape (iii). B) Combining a variety of core and shell allows for printing tubes with different inner diameters. C) By adjusting the flow rate in the shell nozzle permits tubular structures with unique wall thicknesses with a 15/19 gauge coaxial nozzle. D) The 15/19 gauge coaxial nozzle produced successful tubular, vessel like structures with EPCs, AMPS, and EPC/AMPS laden BBVs (scale bar: 500 μm). (Reprinted with permission from ref138. Copyright 2019 Advanced Functional Materials)