In plant-breeding programs, 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 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.
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.
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 machining jig with individual pipettes that simultaneously release liquid. The magnetic blocks bind the magnetic particles in the liquid at the base of the deep-well plates. They 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 liquid exactly into the plates. Festo controllers, motors, and electric axes ensure that the pipetting head can work quickly and accurately to the millimeter. Laboratory-automation solutions like these will increasingly be used in laboratories in future to keep plant breeding competitive.