MECs: "Building Blocks" for Creating Biological and Chemical Instruments
(A) A MEC-based multiscale fluidic router designed to mix fluids from nine different fluid storage MECs in volumes spanning five orders of magnitude (from 400 nanoliters to 10 milliliters). (B) A MEC-based acid-base titration instrument suitable for educational applications in classrooms. By toggling the manual valves SU1, SU2, and SV1, different ratios of water: sodium hydroxide solution: phenolphthalein are delivered to a microcentrifuge vial. The observed range of phenolphthalein colors (from clear in pure water to pink in 4.0 × 10−5 mass concentration NaOH) confirms the successful operation of the instrument. (C) A MEC-based bioreactor capable of culturing cells. The optical density macroMEC (OD1 in Fig 3B) measures the concentration (via optical density) of the cells as they grow and react to stimuli. (D) A growth curve obtained by using the bioreactor in C to culture Saccharomyces cerevisiae yeast cells. The bioreactor is sensitive enough to detect important metabolic checkpoints in the growing yeast, including the diauxic shift (when the yeast cells switch from glycolysis to the aerobic oxidation of ethanol) and the entry into G0 (when the yeast cells exhaust all nutrients and enter stationary phase).