Developmental Pathways Pervade Stem Cell Responses to Evolving Extracellular Matrices of 3D Bioprinted Microenvironments

Figure 1

Fabrication of 3D ECM-based, bioprinted prisms. (a) Fabrication Schematic. Multiphoton excitation was used to polymerize a focal volume containing individual ECM proteins (e.g., FN, Col1, and LN) and associated photocrosslinking agent. 3D printing of this type was used so that a three-dimensional construct, in this case a rectangular prism, could be generated even with ECM types that do not form hydrogels spontaneously ex vivo. (b) Geometric template (above; dimensions of micron scale) and associated bioprinted ECM-based rectangular prism containing BSA and LN (BSA/LN; below). Scale bar = 50 μm. (c) Representative SEM images of prisms fabricated with BSA, FN, Col1, and LN. Scale bar = 10 μm. (d) Average fractal dimension of each ECM-based, 3D bioprinted prism (above); volumetric swelling ratio of each ECM-based bioprinted prism (below). Error bars depict standard deviation (SD), , experimental replicates. (e) Multiphoton imaging to show interaction of hMSCs with bioprinted prism containing BSA only after 3 days of seeding. 3D reconstruction (left) and cut-away view (right) show cellular infiltration (e, upper panels). Also, in support of hMSC infiltration are shown multiple cross sections at various z depths (e, lower panels). Green (CD90) indicates MSCs; red indicates the bioprinted matrix. Scale bar = 100 μm.

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