This release is available in German.
Analysis and diagnosis in a chip format are coming of age, but their practical application has been limited because until now, the sample usually had to be prepared separately and on a nonminiaturized scale. Jrgen Pipper and his team at the Institute of Bioengineering and Nanotechnology in Singapore want to change this. They have now developed a rapid test for genetic diagnosis that combines the preparation of biological samples with a polymerase chain reaction (PCR) on one chip. As they report in the journal Angewandte Chemie, the laboratory device for all steps in this system is a single drop containing magnetic nanoparticles, which is moved across the chip by a magnetic field.
PCR allows gene sequences to be duplicated and identifiedto identify a disease trigger, for example. In this process, the sample must cycle through a specific sequence of temperatures. Because of the slow heating and cooling processes, laboratory PCR usually takes several hours. The new chip PCR requires only minutes, including for the sample preparation.
In contrast to other chip-based methods, the actual sample, such as a drop of blood, can be placed directly on the PCR chip, where it is mixed with a drop that contains magnetic particles. These particles are equipped with antibodies on their surface, antibodies that bind specifically to the interesting cells in the blood. By moving a magnet underneath the chip, a droplet containing the bound magnetic particles is physically pulled out of the blood droplet and moved on to the next stationa droplet of washing liquid. The magnetic droplet is combined with the washing droplet and then pulled out again through movement of the magnet. Another droplet then delivers the enzymes and reagents necessary for cell disruption.
The last station is the PCR station. After combination with a reagen
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