NUCLEIC ACID PURIFICATION SYSTEMS

The need for high quality, highly pure DNA and RNA is important for a wide variety of research and clinical applications. These nucleic acids are being isolated from a variety of sources such as cells (including bacterial cells), PCR reactions, restriction enzyme digestions and agarose gel matrices. Purification methods optimized for various sample types have emerged over time. Modifications are made periodically to improve sample quality and yield, reduce processing time, and to ensure compatibility with existing workflows and equipment.

When isolating nucleic acids from cells, after disrupting the cell membrane to release the DNA, the soluble components of the cell lysate must be separated from the cellular debris and other insoluble materials. Centrifugation and vacuum filtration are frequently used to accomplish this separation, but magnetic clearing has gained wide acceptance more recently.

Magnetic beads are a simple and reliable method of purifying genomic, plasmid and mitochondrial DNA. Under optimized conditions, DNA selectively binds to the surface of magnetic beads, while other contaminants stay in solution. Purified DNA can then be used directly in molecular biology applications such as sequencing or restriction digests. The major advantage of this method is that there is no need for centrifugation or vacuum manifolds, which can be a bottleneck in many automated processes. Separation can be done manually, semi-automated or fully automated using tube strips or microplates.