DNA Isolation

DNA purification methods include traditional organic extraction with phenol:chloroform, Chelex® extraction and the use of silica or cellulose membranes or magnetic resins. Phenol:chloroform extraction uses hazardous organic chemicals, is time-consuming, requires multiple centrifugations, may result in significant loss of material, is not amenable to automation and can introduce amplification inhibitors. DNA extraction using Chelex® resin is rapid but does a poor job of removing organic inhibitors. In contrast, magnetic resin-based DNA purification systems are effective at removing PCR inhibitors, do not require organic solvents and can be easily adapted for automation.

The DNA IQ™ System uses a silica-based paramagnetic resin to isolate DNA from liquid samples and samples on solid supports. It will isolate all DNA types present in a sample, including nuclear and mitochondrial DNA. For samples with abundant DNA, such as buccal swabs collected as reference samples, the amount of DNA IQ™ Resin used is limiting so that the resin becomes saturated and any excess DNA is not bound, leading to the isolation of a consistent amount of DNA from all samples. For casework samples with limited DNA amounts, the resin is not saturated, and the amount of DNA isolated is limited only by the amount of starting material. The DNA IQ™ System allows DNA isolation from a wide variety of sample types, including blood and blood stains, semen and semen stains, chewing gum, hair, bone, urine, cigarette butts, buccal swabs and blood card punches.

The Maxwell® FSC instrument is a magnetic particle handler that is used together with the DNA IQ™ cartridge-based casework kit to purify DNA from up to 16 samples in about an hour. For higher throughput DNA purification needs, the DNA IQ™ chemistry can be scaled for use on automated liquid handling systems.