Figure 7-.

Co-axial multi-material bioprinting technologies. A) Custom-designed multi-layered co-axial nozzles with various diameters. Reproduced under the terms of the CC-BY Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0).^[264] Copyright 2017, The Authors, published by Springer Nature. B) Schematic illustration of multi-material bioprinting of a tubular tissue using a blend of PEG and PEGOA in GelMA/alginate as the bioink. Reproduced with permission.^[146] Copyright 2018, Wiley-VCH. C) Using microfluidic systems to achieve a crosslinked Janus flow pattern of multiple cell-laden bioinks via a co-axial nozzle. Reproduced with permission.^[80] Copyright 2017, Elsevier. D) A multi-scale fluidic system used for biofabricating vessel-like structures made of alginate. E) Multi-scale perfusable vessel-like constructs, (a) Samples of single-layer and double-layer constructs, (b, c) Photographs of the single-layer construct, (d, e) Photographs of the double-layer construct, (f) Scanning electron microscopy of the longitudinal section. F) Bioprinted multi-cellular vessel-like structures (red: L929, green: MOVAS, and orange: HUVEC). Reproduced with permission.^[148] Copyright 2017, American Chemical Society.