Precise and maintenance-free linear axis for DNA diagnostics in the laboratory

Diagnostics in the field of genetic mutations (e.g. for the early detection of cancer) should recognise genetic changes before the clinical symptoms of their presence become visible. Therefore, the decisive parameter of successful techniques for detecting small genetic variants is their sensitivity. Here, for example, native nucleic acid electrophoresis, known as SSCP, is used. The most important physical conditions that influence ssDNA conformers and SSCP patterns are: pH, ionic strength, but also temperature. However, temperature control during electrophoresis is a major problem due to the heat generated by the current flow. However, it is important as it has been shown to increase the mutation detection rate. A multi-temperature SSCP device has been developed, the DNA Pointer System, which performs genetic analyses by electrophoretic separation and sequentially changing gel temperature.
An electrophoresis gel is pressed against the heat exchanger. In order to enable uniform heat distribution in the gel, electrophoretic glass plates must be precisely bonded to the heat exchanger. In the system's predecessor model, glass plates were manually inserted into the electrophoresis chamber and held in place by two clamping cam levers. To improve device handling and, above all, safe temperature control during electrophoresis, a suitable linear bearing solution was to be found instead of cam levers.

One of the main components of the latest version of the DNA Pointer system are drylin® SHTspindle liner tables in combination with a NEMA 23 stepper motor from the drylin® E product portfolio, which is controlled by a microprocessor system.
The use of the drylin® E system enabled automated, precise and uniform pressing of the electrophoretic glass plates with the polyacrylamide gel onto the heat exchanger. It significantly improved the quality of the electrophoretic separation of analysed samples compared to the previous version of the DNA pointer system. Improved temperature control directly influenced the results of the SSCP procedure and led to a more reproducible and sensitive detection of mutated genetic variants in the analysed genes. Following the evaluation tests, the drylin® system is now being considered for subsequent installation in some pre-series devices.