The Qiagen QIAamp^® DNA Micro Kit, a spin column using a silica-based extraction method, is used in forensic DNA laboratories. This kit does not require the use of hazardous chemicals. Nucleic acids are attracted to the silica bead under high chaotropic salt concentrations. The sample and lysis buffer (provided in the kit) are added to a sterile tube. The lysate is combined with alcohol and placed into the spin column, which is inserted into a tube. The removal of proteins and divalent cations is accomplished using multiple buffer washes and centrifugation steps. Removal of cations, such as Mg²⁺, prevents nucleases from further degrading the DNA. Pure DNA is eluted from the membrane into sterile water or TE buffer.

Qiagen produces several types of kits under the QIAamp^® name, including kits specific to the extraction of whole liquid blood, feces, hair, dried stains, and swabs. The primary difference in these kits is the type of wash buffers provided.^3,4,5

There are other proprietary spin columns that use glass fiber, silica, and paramagnetic particles. These include, but are not limited to, the following:

• Amersham Biosciences (part of GE Healthcare) produces kits, such as the GFX™ Genomic Blood DNA Purification Kit, that rely upon a glass fiber matrix packed into a spin column.
• UBI Life Sciences markets the Omega Bio-Tek E.Z.N.A.^® Forensic DNA and E.Z.N.A.^® Mag-Bind^® Forensic DNA Kits.
  • The E.Z.N.A.^® Forensic DNA Isolation Kits use a silica-based material, combined mini-column spin technology — HiBind^®.
  • The E.Z.N.A.^® Mag-Bind^® Forensic DNA Kit uses paramagnetic particles, Mag-Bind^® particles for DNA isolation.

Back Forward