Fig. 5
From: Monitoring and external control of pH in microfluidic droplets during microbial culturing
Development of fluorescent signal of E. coli MG1655 cultured in droplets under pH regulation. Like in experiments before, droplet populations were incubated in customized droplet incubators. Fluorescence of 6-carboxyfluorescein was monitored constantly as indication for pH development. When the fluorescence signal dropped below a value of 1, diethylamine dissolved in a ratio of 1:100 in the perfluorinated oil with surfactant at working concentration was administered by pipetting to the droplet population. a Fluorescence intensity over time for two droplet populations containing E. coli MG1655. One of them was treated with diethylamine and one served as untreated control. On the second y axis the cumulative amount of diethylamine treated oil added during the incubation is plotted. b Cell densities, glucose consumption and final pH measured with a pH electrode are compared for the regulated and not regulated droplet population