Fig. 5.

Demonstration of viscous fingering in phantoms made of tofu embedded in heparin or, vice versa, heparin embedded in a tofu matrix. The enclosed material (stained blue) is intended to mimic the tumor’s viscous behavior when growing within a less viscous environment (MEN, Top) or within a more viscous environment (GBM, Bottom). The snapshot images were taken from underneath the glass cylinder while pushing a stamp onto the phantom to induce spread. A sketch of the experimental setup is shown on the left-hand side. Red arrows indicate sites of viscous fingering.