Fully automated DNA extraction

Article of 26 October 2018 

Laborautomatisierung

In plant breeding, countless DNA samples are examined in the laboratory every day. Breeders face the technical challenge of testing DNA quickly and accurately. An automated fixture supports the laboratory in the preparation of samples for analysis.

In plant breeding programmes, the DNA of leaf and seed tissue is microbiologically examined to determine properties such as disease resistance or vitamin content. The analysis must be carried out quickly and very precisely. It is extremely important that the results are error-free and can be reproduced. For this purpose, laboratories carry out exactly the same tests several times in succession. It must also be possible to verify which analyses have already been carried out. Another central criterion is the traceability of the samples: it must be clear at all times which sample is involved in order to avoid confusion.

Automated preparation of DNA samples

Today, automated systems can support virtually the entire analysis process – from sample identification and sampling to preparation and actual testing. This frees the laboratory staff from monotonous, repetitive tasks and gives them more time for demanding tasks. At the same time, the analysis is faster and the quality of the results increases.

An important step in the analysis process is to remove contamination from the DNA. In an automated laboratory, this task is performed by a DNA extraction robot, which uses a special extraction chemistry that contains magnetic particles. These particles bind the nucleic acids that make up DNA. The contamination is then removed with water and the DNA is ready for the following molecular biological analyses.

The extraction robot in action

The extraction robot in action

For the cleaning process, the DNA samples are stored in so-called deep-well plates, which are specially designed for the storage of laboratory samples. Eight permanent magnets are mounted underneath the plates. The extraction robot introduces the extraction chemistry into the plates using a 96-fold pipetting head – a fixture with individual pipettes that simultaneously release fluid. The magnetic blocks bind the magnetic particles in the fluid at the bottom of the deep-well plates and can therefore be easily separated from the DNA. It is then cleaned with water and is available for further testing.

During the extraction process, the robot must work very precisely. It must position the pipetting head reliably in order to fill the fluid exactly into the plates. Festo controls, motors and electric axes ensure that the pipetting head can work quickly and accurately to the millimetre. Laboratory automation solutions like these will increasingly be used in laboratories in future to keep plant breeding competitive.