Bioprinting of Vascularized Tissue Scaffolds: Influence of Biopolymer, Cells, Growth Factors, and Gene Delivery

Figure 3

(a) Microfluidic vessel networks: schematic cross-sectional view showing (i) morphology and barrier function of endothelium, (ii) endothelial sprouting, (iii) perivascular association, and (iv) blood perfusion, (b) schematic of microfluidic collagen scaffolds after fabrication, (c) Z-stack projection of horizontal confocal sections of endothelialized microfluidic vessels showing (i) overall network, (ii) views of corner, and (iii) branching sections (scale bar: 100 μm ((a), (b), and (c) were reproduced with permission from [101]), (d) tube formation of autologous endothelial progenitor cells from adipose tissue in 3D scaffolds before and after labeling with lipophilic fluorochrome chloromethylbenzamido dialkylcarbocyanine showing the formed capillary-like structures in the Matrigel, (e–h) after seeding on BAM (cells, dual positive fluorescence, cell nucleus, and capillary-like structures are in red, yellow, blue, and green colors, respectively, scale bar = 100 μm, reproduced with permission from [102]), (i–k) stereomicroscopic images of HOB-HDMEC spheroids indicated by arrows: (i) directly, (j) day 3, and (k) day 14 after transplantation (scale bars = 13 mm, reproduced with permission from [103]), (l) a vascular network after nine days in culture, a channel (optical thickness and z-position = 10 μm) showing the endothelial monolayer lining the vascular lumen (scale bar = 200 μm), and (m) endothelial cells formed single and multicellular sprouts from patterned vasculature, as shown in a z-stack (optical thickness = 200 μm) from deeper within the gel (z-position = 300 μm, left) ((l) and (m) were reproduced with permission from [22]).