Fig. 3

Fast media switches using the elastomer microchips. a. Schematic of the setup used for switching media. Flow sensors (FS) modulate the operation of a pressure controller to maintain an accurate flow rate. Media switches are achieved using valves. Vacuum-based bubble traps (BT) limit the presence of bubbles (BTs were added when using cells but not in b-d). b-d. All experiments used chips as in Additional file 4C. b. Media switch dynamics. 50 μM Rhodamine B was perfused in the chip (20 μL/min) for 10 min. Water was then injected (20 μL/min, T = 0), and fluorescence intensity was followed over time. The chip was then re-used twice with the same protocol but with water perfusion at 10 μL/min followed by 5 μL/min. Data were corrected for the background (measured prior to the initial Rhodamine B injection) and normalized to T = 0 for each flow rate. c. Influence of the position within the channel on the media switch dynamics. 5 μM Rhodamine B was injected (20 μL/min) for 10 min prior to switching to water (20 μL/min, T = 0). Fluorescence intensity was then measured over time at various distances from the channel border. Data were corrected for the background (measured prior to the initial Rhodamine B injection) and normalized to T = 0 for each position. d. Reproducibility of the media switch dynamics. 50 μM Rhodamine B was injected (20 μL/min) for 10 min. At T = 0 and T = 13.5 min (asterisk), the perfusion was switched to water (20 μL/min) and back to Rhodamine B, respectively. Fluorescence intensity was then followed over time (Experiment 1). The same chip was re-used in an identical experiment (Experiment 2). Data were corrected for the background (measured prior to the initial Rhodamine B injection) and normalized to T = 0 for each experiment