what is the purpose to include ficoll in the loading stop bu

what is the purpose to include ficoll in the loading stop buffer?

Solution

Ficoll is a polysaccharide which is highly branched and readily dissolves in aqueous solutions. The polysaccharide sucrose is made to react with epichlorohydrin , in order to prepare ficoll. Ficoll is used in the loading stop buffer to separate blood and it\'s components - erythrocytes, leukocytes etc.

Principally, while separating lymphocytes and monocytes, density of Ficoll is higher, whereas, the density of erythrocytes and polymorpho nuclear leukocytes is higher than that of ficoll. During the run, addition of ficoll as the loading dye along with orange G dye, renders Brighter and tighter bands as compared to the standard glycerol loading dyes. Addition of ficoll, in place of glycerol, is just to increase the density of the sample. This makes the sample denser than water so that it would sink to the bottom of the gel , when we are loading the sample onto the gel.