DNA extraction from low volume blood samples

Blood collection

  1. Blood (20 μl) can be collected from capillary sampling.
  2. Put the sample in an equal amount of Trizol in a 1.5 ml centrifuge tube.

DNA extraction

  1. Centrifuge the Trizol/whole-blood mixture (5 min, 12000 g, 4°C)
  2. Add 10 μl of chloroform, vortex 2-3 min and centrifuge (15 min, 12000 g, 4°C).
  3. If RNA is to be extracted, transfer the upper aquatic phase to a fresh tube, otherwise discared the upper phase.
  4. Transfer the remaining supernatant to a fresh tube and add 10 μl of 100% cold methanol, incubate on ice for 5 min.
  5. Centrifuge (5 min, 2000 g, 4°C), discard the liquid phase and resuspend the pellet in 75% ice cold ethanol. Incubate 30 min, dry and add 5 μl of DPCE treated water.

RNA extraction

  1. Mix the aquaous phase separated from step 3 with 10 μl of ice-cold isopropanol. Centrifuge (10 min, 12000 g, 4°C).
  2. Discard the supernatant, add 75% ice-cold methanol, centrifuge (5 min, 7500 g, 4°C).
  3. Dry the pellet and add 5 μl of DPCE treated water.

DNA and RNA quality and quantity

Determine quantity and quality using a spectrophotometer with DEPC water as blank.