High-throughput isolation of genomic DNA from forensic samples—NucleoSpin 8/96 Trace

NucleoSpin 8/96 Trace kits are designed for the preparation of highly pure genomic DNA from small amounts of any tissue, cell, or forensic sample (e.g., buccal swabs, blood spots, cigarette filters). The obtained DNA can be used directly as template for PCR.

Lysis is achieved by incubation of samples in a solution containing chaotropic ions in the presence of Proteinase K. If subsequent separation of the lysate from the sample material is difficult, the lysate can be separated from the forensic material under vacuum or centrifugation using the NucleoSpin Trace Filter Plate (not included in the kits). Appropriate conditions for binding of DNA to the silica membrane in the NucleoSpin Trace Binding Strip/Binding Plate are created by addition of isopropanol to the lysate. The binding process is reversible and specific to nucleic acids. Contaminants are removed by two washing steps with ethanolic buffer. Pure genomic DNA is finally eluted under low ionic strength conditions in a slightly alkaline elution buffer.

Typically, 1–2 µg genomic DNA can be purified from buccal swabs. The final concentration of eluted DNA ranges from 10–20 ng/µl (depending on the elution buffer volume) and the A_260/280 is 1.8–1.9. The kits can be used manually under centrifugation or vacuum and can also be automated on common liquid handling instruments.