To provide a functional measure to evaluate the efficiency of the medium exchange, we performed electroporation on released cells in a micropulser. Electroporation efficiency is very sensitive to high conductivities of the liquid phase of the cell suspension. For example, remaining growth medium drastically increases the conductivity and leads to a low time-constant in the micropulser (ESI Eq. 2). For performing electroporation experiments, we transferred 20 µL of the sample into a 0.1 cm electroporation cuvette (Cell Projects Ltd) that had been pre-chilled on ice. An aliquot of 1 µL plasmid pUC19 (dissolved in 10 mM Tris-HCl (pH 7.6) and 1 mM EDTA, Thermo Scientific) was added to the cell solution for a final concentration of 2.0 ng µL -1 . After inserting the cuvette into an electroporator (MicroPulser, Bio-Rad), we applied a 1.8 kV pulse with a discharge time constant of about 6 ms. The time constant from the electroporator is a function of the sample conductivity and was used as a measure of success of the medium exchange. Immediately after the pulse, 980 µL of room temperature SOC medium 1 was added to the cuvette for cell recovery. The complete volume was transferred into a tube and placed in a shaking incubator (37 • C, 200 rpm) for one hour to allow expression of the antibiotic resistance gene on the plasmid without allowing for growth to resume. Afterwards, we plated 40 µL of the cell suspension on LB agar plates containing 50 µg mL -1 of the antibiotic carbenicillin. The plates were incubated overnight at 37 • C and CFUs were determined the next day.