Figure 4. Conditioning microvascular constructs to promote stability and maturation.

Several methods exist for conditioning microvascular networks, including: (A) the use of co-culture systems that mirror the heterotypic cell-cell signaling inherent within the vascular niche, (B) heterogeneous substrate cues, and (C) the use of fluid flow to mechanically condition the network. Topographic patterns are one aspect of substrate heterogeneity that can be fabricated through a variety of methods (D-F). (D) Soft lithography can be used to make simple gratings, hierarchical gratings, convex microlenses, concave microlenses, pillars, and holes at the micro- and nanoscale. (E) Electrospinning can create nanofibers aligned parallel or perpendicular to the seeded cells, or not aligned at all. (F) Based on print resolution, the printed construct can contain grooves and surface features that influence cell alignment, migration, and adhesion similarly to the patterns formed in (D) and (E).