Agarose beads are small spherical beads of agarose gel which are commonly used in gel filtration or molecular size exclusion chromatography and biomolecular purification and immobilization. These beads act as porous gel to filter mixtures of molecules based on their individual sizes. And since these beads are easy to activate, they can also be used to bind biomolecules in a reversible or irreversible manner. In addition, their inert nature and unique internal surface area can also be activated for ligand attachment, making them the ideal basis for various affinity chromatography beads such as protein A and G, and glutathione.
Some researchers are confused whether they should use agarose or Sepharose beads for their experiments but this really doesn't matter since both refers to the same product. Sepharose is just a registered trademark for agarose beads used by GE Healthcare.
Agarose beads are available in different concentrations of agarose (2%, 4%, and 6%) that alter the separation range and bead size of the agarose beads. 2% agarose has a particle size ranging between 60-200µm while 4% and 6% have particles ranging between 45-165μm. Agarose beads exhibit broad fractionation ranges and have high exclusion limits and negligible non-specific adsorption as well.
It is interesting to note that as agarose concentration increases, its porosity decreases. This unique characteristic increases the rigidity of the agarose chains and alters their fractionation range. This also makes them ideal for cleaning up and separating a mixture of molecules in a sample based on their individual sizes or molecular weights (MW).
