selektor 1976-05

For the first time the iron content of red blood corpuscles has been used to separate them from other blood components. The red cells are magneti- cally attracted to a very simple form of steel wool filter, a technique that promises to be valuable in research as well as in medical practice. Red blood cells are small disc-like bags, 8 µm in diameter, occupying 45 to 50 per cent of the total blood volume. They contain a solution of the blood pigment haemoglobin. A molecule of haemoglobin has approximately 10 000 atoms, of which only four are iron. The iron atoms are essential to the respir- ation process and they give the blood its characteristic red colour. They are important in the separation process because through them there is enough iron present to make the red blood cells very weakly paramagnetic when in their de-oxygenated state, so that they experience a force in the presence of a magnetic field.