Figure 1. Fibrin gel polymerization and imaging setup.

Porous polyethylene blocks were cut to size, coated with fibrinogen, and adhered to polyethylene terephthalate frames which were then loaded into molds (a). Immediately after combining thrombin and fibrinogen, the solution was pipetted into the frame-loaded molds prior to polymerization, and the frame-gel assembly was removed from the molds following fibrin polymerization (b). A representative $2\mathrm{m}\mathrm{g}/\mathrm{m}\mathrm{L}$ fibrin gel with visible porous polyethylene blocks (c). A bath with a rotatable mounting system was designed (d) and 3D printed (e) to facilitate imaging of fibrin gels from 2 different orientations. A separate mounting system was designed (f), 3D printed (g), and combined with a micromanipulator (h) to image the fibrin gels during deformation while minimizing vibrations to improve image resolution.