Agaros

Agaros, commonly referred to as agarose, is a natural polysaccharide derived from agar, a gel-forming carbohydrate extracted from certain red algae such as Gelidium and Gracilaria. It represents the purified, linear fraction of agar that forms gels, and is widely used in laboratory settings for its predictable, inert gel matrix. The polymer is composed of repeating disaccharide units called agarobiose, giving agarose a high molecular weight and a structure that sieves molecules by size.

In solution, agarose is dissolved in warm buffer and then allowed to cool. As it cools, it forms a semi-solid gel whose pore size depends on the agarose concentration and the ionic conditions of the buffer. Typical concentrations for molecular biology range from about 0.1% to 2% weight/volume, enabling tunable separation of nucleic acids. The gels are clear and easy to cast, and they can be stained with dyes to visualize separated samples.

The primary use of agarose is in gel electrophoresis, especially for separating DNA and RNA fragments by size. It provides gentle, size-dependent sieving that facilitates analysis of nucleic acids after amplification or digestion. Agarose gels are also employed in some laboratory workflows for education, routine verification of nucleic acid integrity, and as components of certain chromatographic matrices when converted to bead form for size-exclusion applications.

Agarose is valued for its natural origin, relative chemical inertness, and ease of handling, making it a standard material in molecular biology and related fields.