Cell-membrane and rheological mechanisms: dynamic osmotic hemolysis of human erythrocytes and repair of ghosts,as studied by resistive pulse spectroscopy

Normal human erythrocytes undergoing abrupt osmotic hemolysis display a single, transient, localized circular rupture over 15 to 20% of their total surface area. An immediate and striking drop in apparent volume for such cells, as measured by electronic “sizing” using resistive pulse spectroscopy (RPS), is ascribed primarily to a greatly increased, flow-induced, cell-membrane deformation and associated expulsion of ghost contents rather than to an intrinsic property of hemolysis per se. The time and flow-rate dependence of the RPS spectra measure the rates of ghost formation and repair of the hemolytic lesion in the membrane. Restored ghosts rehemolyze at a critical volume and lesion size similar to those of the original lysing cells. Membrane rather than cytoplasmic (internal viscosity) properties dominate deformability measured from RPS spectral shape.