Hello Elizabeth Reinhart

Histopaque-1077 is a sterile solution of poly sucrose and Hypaque (sodium diatrizoate), adjusted to a density of 1.077g/mL. It is Hypaque that contains a significant concentration of iodine that may be toxic to the cell membrane and affect the results.

On the other hand, Ficoll is a neutral, highly branched, high-mass, hydrophilic polysaccharide which dissolves readily in aqueous solutions. In fact, it is minimally osmolalic in comparison to sucrose density gradients.

Best.

Hi Elizabeth,

Long exposure to Ficoll is toxic to cells but during the PBMCs purification protocol, the blood is not mixed with the Ficoll-Paque. The effect on cells depends on the study that is going to be done with the separated cells, it could affect or not, in terms of, for example, elemental concentrations, as described in 'Impact of Ficoll density gradient centrifugation on major and trace element concentrations in erythrocytes and blood plasma' (PMID : 25240911). Usually, diluted blood is added very slowly by sliding it down the wall of the slightly lying tube that then is carefully placed upright position to prevent the blood from mixing with the Ficoll-Paque, avoiding contact with the cells, additionally, once the cellular ring is extracted, two saline washes are carried out to eliminate Ficoll remains.

It should not be toxic to cells if you remove the cells from the gradient right after the centrifugation step and wash them well and then put them in seeun containing medium.