Agarose

Agarose Powders and Precast Gels

Bio-Rad offers a variety of agarose powders and precast agarose gels to meet all your needs for DNA and RNA electrophoresis, including pulse field gel electrophoresis and specialty applications such as IEP and IEF. Powders are certified genetic quality tested DNA agarose. Our precast gels are available both in TBE or TAE buffer, with or without ethidium bromide.

Agarose Types and Uses in Electrophoresis

All Bio-Rad agarose products are guaranteed to be free of inhibitors, DNases, and RNases. There is a range of types of agarose that have been optimized for different uses.

Molecular biology agarose: This is a general-purpose agarose that has a high exclusion limit. This type of agarose has high gel strength and is easy to handle at low percentages. Molecular biology agarose is GQT (genetic quality tested) grade, making it ideal for preparative gels and recovery of DNA. Analytical separation is >1,000 base pairs (bp).

Low-melt agarose: The main use of low-melt agarose is for preparative electrophoresis. It is ideal for in-gel applications such as ligation, PCR, restriction enzyme digestion, transformation, and sequencing. Other applications include pulsed field electrophoresis of megabase DNA and embedding chromosomes. This agarose has a gelation temperature of 26°C and high resolving capacity, >1,000 kb.

Low-melt agarose is also used to secure immobilized pH gradient (IPG) strips for isoelectric focusing, the second dimension of 2-D SDS-PAGE. This agarose contains bromophenol blue for monitoring electrophoresis.

PCR agarose: This high-strength agarose forms gels that are easy to handle and remain flexible even at high gel percentages, reducing the risk of cracking or breaking. Gelation temperature is 40°C. This agarose has excellent sieving properties and the highest gel strength of all the agaroses.

PCR low-melt agarose has a high sieving capacity. It is ideal for preparative electrophoresis and in-gel applications such as restriction enzyme digests, ligation, and transformation. PCR agaroses are recommended for DNA fragments <1,000 bp.

Low range ultra agarose: This agarose provides resolution of primers and small PCR products at lower concentrations than standard agarose, avoiding the need to use polyacrylamide. A 3% gel clearly resolves a 10 bp ladder. Analytical separation is 20–800 bp.

Megabase agarose: This agarose has a very high gel strength, high electrophoretic mobility, and high exclusion limit. Megabase agarose is the best choice for clamped homogeneous electrical field (CHEF) and field-inversion gel electrophoresis (FIGE) applications. The gels remain easy to handle at concentrations as low as 0.3% and allow shorter run times. Low background staining also provides superior imaging of high molecular weight DNA. The separation range is between 1 kb and 5 Mb.

Pulsed field agarose: Pulsed field gel electrophoresis (PFGE) is used for separation of large DNA fragments. Although gels cast with this agarose have longer PFGE run times than with megabase agarose, running conditions for this agarose are a preset, selectable, protocol for the CHEF Mapper® XA system auto-algorithm. The separation range is 1 kb to 2 Mb.

Agarose for IEP and IEF: Agaroses are available for immunoelectrophoresis (IEP) and isoelectric focusing (IEF). They can be used for determining relative molecular weights (Mr). The agarose for IEF has no detectable electroendosmosis.

Precast Agarose Gels

Precast agarose gels have several advantages, in addition to speed and reproducibility. The locking tray means that the agarose gels do not move during loading and at the beginning of a run, which can waste sample, give uneven loads, and decrease band sharpness. The UV-transparent tray has fluorescent numbered wells that help keep track of loading patterns when there are many samples, as well as a fluorescent ruler down one side for measuring migration.

A wide variety of gels, 1 and 3% agarose, TBE and TAE, and with and without ethidium bromide, is available. Well configurations suit needs from preparative to screening large numbers of samples (up to four rows of wells). The uniformity makes precast agarose gels easy to load with a multichannel pipet.

Precast agarose gels provide excellent separation and resolution of DNA, and are compatible with most submarine horizontal electrophoresis systems.

More Information on Agarose

Agarose is a linear polysaccharide made of repeating units of agarobiose that is extracted from boiled red algae. It's neutral charge, low gelling temperature, and the formation of stable gels with large pore sizes makes agarose a good medium for electrophoresis and chromatography. Agarose gels are easy and quick to set up, and can separate DNA fragments ranging from about 20 bp to many megabases. Agarose beads are used extensively for column chromatography, particularly in size exclusion and affinity chromatography.

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