DNA Biobank with Automated DNA Extraction and Normalization

Successfully building up a Biobank requires many individual steps from sample collection, processing, storage and fast retrieval of specific samples when needed. The system described here fully automates DNA extraction from human blood samples (up to 3 ml), DNA normalization, and storage at/retrieval from -20°C. The automated method results in a standardised process with highest accuracy and reproducibility. At the same time, the full chain of custody from the blood samples down to the normalised DNA samples in the storage system is recorded automatically.

Benefits

• Chain of custody recorded automatically (Sample Tracking)
• Standardized sample handling and higher quality results
• High throughput for labor intensive processes
• Process up to 48 samples without user intervention
• Process up to 96 samples per 8 hour shift
• Modular capacity to grow with your needs

Protocol

The system uses the INVITROGEN GeneCatcher Midi kit with magnetic beads to extract DNA from primary blood samples. While loading of the primary samples, the barcodes of all samples are read and stored in the database.

DNA Binding

After preparing the extraction plates with 60 μl magnetic bead solution and 2.5 ml Lysis buffer, 1 ml of blood is added to each well. In order to increase final DNA amount, a total of 3 ml of each primary sample is distributed equally into 3 wells of the extraction plate. After initial lysis and removal of the supernatant, the samples are subjected to a protease digestion at 65°C in order to remove any protein that potentially binds DNA and thus could compromise DNA quality and yield. Using the CO-RE Grippers, the plates are moved between the heating/shaking positions (incubation steps) and the magnet positions where the beads are held back in the wells (pipetting steps). Using HAMILTON’s Tip Cutter, the diameter of the opening of the standard tips can be flexibly enlarged for challenging pipetting steps during the complete process (removal of cell debris, pipetting of viscous solutions).

DNA Elution

After four subsequent washing steps, 250 μl elution buffer is added to the individual wells, the plates are lidded and incubated at 65°C with gentle shaking on the HAMILTON Heater Shaker to elute the DNA from the magnetic beads. The eluates are then transferred into an intermediate deep-well plate, where the three aliquots of each primary sample are combined. An aliquot of each sample is subjected to an absorbance measurement at 260/280 nm (Biotek PowerWave) in order to calculate purity and amount of DNA.

DNA Normalization

Using the results of the absorbance measurement the final DNA concentration is adjusted to a user specified value in the final MATRIX storage tubes. DNA from each primary sample is stored in two different tubes.

Storage

The MATRIX tube racks are then transported to the asmServer via an integrated hand-off arm. Inside the asmServer, the internal 1D and 2D barcode reader registers each individual tube before storing it in the asmStore. This guarantees a complete chain of custody from the blood samples up to the normalized DNA samples stored in one of the -20°C asmStore modules.