From picoliter droplet to agar plate

New method links microfluidics to microbiology

Hundreds of droplets in the colors green, red and yellow. In the left area, only the color dots are visible, and to the right, the droplets.
Microfulidics allows millions of microorganisms to be examined simultaneously. Each 100-picoliter droplet, color-coded here, contains one culture. Source: Martina Graf/Leibniz-HKI

Researchers at Leibniz-HKI have developed a method for transferring microbial cultures in tiny droplets to larger cultures, thus creating a fast and simple link between the high-throughput method of droplet microfluidics and classical microbiology. Samples of interest can be transferred to for example agar plates for further biotechnological research and detailed analysis.

Every habitat on earth is colonised by a multitude of microorganisms, only a fraction of which are known or even studied. These bacteria, archaea, fungi, algae and other microscopic organisms hold a huge treasure trove of molecules that are, for example, of medical or chemical interest or could be used industrially.

Due to the huge number of different organisms, high-throughput methods are needed to isolate a single specific variant - be it from mutant libraries containing millions of variants or from complex environmental samples, like groundwater and soil samples from exotic habitats. Miriam Agler-Rosenbaum's group uses droplet microfluidics for this purpose.

The problem so far has been to transfer these droplets to classical microbiological cultivation, something the researchers have now found a practicable solution for. "The ability to deposit a droplet of interest and still correlate every single droplet to a single colony delivers enormous benefits for screening new biotechnologically interesting microorganisms or for isolating new microbial species," they write in an article recently published in the journal Sensors and Actuators B: Chemical.

Original publication

Weber T, Hengoju S, Samimi A, Roth M, Tovara M, Agler-Rosenbaum M (2022). Recovery and isolation of individual microfluidic picoliter droplets by triggered deposition. Sensors and Actuators B: Chemical, doi: 10.1016/j.snb.2022.132289


Miriam Agler-Rosenbaum
Sundar Hengoju
Martin Roth
Ashkan Samimi
Miguel Angel Tovar Ballen
Thomas Weber