Fig. 1. Fabrication, 3D gauging, and perfusion of FRESH-printed CHIPS.
(A) Schematic of the FRESH bioprinting and release process. (B to D) CAD design (i); FRESH printing using a collagen bioink (ii); volumetric OCT imaging revealing high-resolution control over collagen extrusion and negative space resulting in patent lumens (dark regions) (iii); and 3D gauging of the negative space luminal region with histogram of the over and under print error for quantitative fidelity assessment of serpentine, triple, and stacked channel internal network designs (iv). (E) A multi-scale vascular bed design with open lumens from 1 mm to 250 μm. (F) Multi-scale vascular bed FRESH printed from collagen I. (G) Perfusion of blue dye through the multi-scale vascular scaffold. (H) Volumetric OCT imaging and cross-sectional analysis demonstrating lumen patency and circular fidelity of the internal fluidic network. (I) 3D gauging of the multi-scale vascular lumen volume reveals high-fidelity printing with average deviations <11 μm.