Isolation of human peripheral blood mononuclear cells by flotation (iodixanol mixer technique)
The most commonly used technique for the isolation of peripheral blood mononuclear cells (PBMCs) from human blood is to centrifuge whole blood (diluted 1:1 with saline) over an isoosmotic 1.077 g/ml density barrier.
For more information see Application Sheet C03. An alternative strategy devised by Ford and Rickwood  simplifies the procedure. A 19% (w/v) Nycodenz® solution (ρ = 1.100 g/ml), produced commercially as NycoPrep™ Mixer, was added to an equal volume of whole blood to raise the density of the plasma to 1.077 g/ml.
During centrifugation at 1500 g for 30 min at
20°C the erythrocytes and polymorphonuclear leukocytes (PMNs) sediment while the PBMCs float to
the top and are recovered from the meniscus and the medium below it. NycoPrep™ Mixer is no longer
available but the technique has been adapted very successfully to the use of OptiPrep™ and is described