Final Report Summary - DEVMICRO (Directed Evolution in Femtolitre Microreactors - Exploring 'Promiscuity Space') The use of water-inoil droplets as microreactors to carry out chemical and biochemical experiments relies on the assumption that the contents of droplets are not leaking out into the oil phase and there is no communication between the reaction vessels. To assess the mechanism of possible leaking, the retention of various fluorescein derivatives from droplets formed in mineral oil and stored for hours in a reservoir on chip was studied. Leaking into the oil phase was observed and was shown to be dependent on the charge of the compounds and on the concentration of the surfactant used. We found that the addition of bovine serum albumin substantially reduced leaking.The improved retention of small fluorescent molecules inside droplets on chip using our modified formulation was demonstrated by single-cell experiments in which encapsulated E. coli cells producing an enzyme were distinguished clearly from those without cells, suggesting that cross contamination of product was minimized. Related documents final1-221761-742186-courtoisreport.pdf
