Figure 1: (a) Schematic representation of the 3D cell culture device. A microfluidic chamber is imprinted on polydimethylsiloxane (PDMS) using soft lithography and reversibly bonded to an optically absorbent substrate. Tubing is connected at the inlet and outlet ports. Fluid is introduced at the inlet and is drawn through the device by applying negative pressure at the outlet. (b) A prototype device is shown with fluidic tubing connected at the ports. In this design, the hexagonal chamber is approximately 9 mm × 5 mm; the PDMS piece and accompanying substrate are approximately 30 mm × 15 mm.