After capturing, washing and releasing bacterial cells, we determined whether the medium exchange from growth medium to ultrapure water was sufficient for biological applications. Therefore, we mixed the released cells in the liquid in which we had recovered them with the DNA of a 2.7 kB reference plasmid, pUC19 and electroporated them using a micropulser. Cells released from the acoustofluidic device exhibited a time constant of between 5.6 and 5.8 ms. In general, a time constant above 5 ms is a strong indicator for high transformation efficiency and indicates that the media was, in fact, exchanged very effectively. We performed electroporation in the micropulser on a dilution series of LB in ultrapure water to estimate the achieved grade of medium exchange. The time constant of around 5.7 ms reached by our sample corresponds to a dilution of 1:256 of LB in ultrapure water. We next examined successful transformation by plating the electropulsed cells on selective media. We measured around 40 000 successfully transformed colonies per electroporation of our acoustically washed cells, resulting in a transformation efficiency of 10 6 transformations per microgram of plasmid, which is perfectly acceptable for transformation events. This high ratio of transformants further indicates that our medium exchange method does not negatively impact the cell viability. The reduced number of transformants relative to a standard lab protocol originates from a surplus concentration of added DNA as well as a decreased cell concentration compared to typical lab protocols. The cells released without acoustics as well as those without medium exchange yielded fewer than 250 CFUs per run on selective plates. The significantly higher transformation efficiency of cells washed with our device highlights that the presented acoustofluidic device is highly beneficial for medium exchange and in particular for the preparation of cells for electroporation, as often required in biotechnology. With our new device and our simplified protocol, we present a quick and viable alternative to centrifugation which allows us to also handle small sample volumes.