AMPHIPHILE INDUCED ECHINOCYTE-SPHEROECHINOCYTE TRANSFORMATION OF RED-BLOOD-CELL SHAPE

A possible physical explanation of the echinocyte-spheroechinocyte red blood cell (RBC) shape trans formation induced by the intercalation o f amphiphilic molecules into the outer layer of the RBC plasma membran e bilayer is given. The stable RBC shape is determined by the minimiza tion of the membrane elastic energy, consisting of the bilayer bending energy, the bilayer relative stretching energy and the skeleton shear elastic energy. It is shown that for a given relative cell volume the calculated number of echinocyte spicula increases while their size de creases as the number of the intercalated amphiphilic molecules in the outer layer of the cell membrane bilayer is increased, which is in ag reement with experimental observations. Further, it is shown that the equilibrium difference between the outer and the inner membrane leafle t areas of the stable RBC shapes increases if the amount of the interc alated amphiphiles is increased, thereby verifying theoretically the o riginal bilayer couple hypothesis of Sheetz and Singer (1974) and Evan s (1974).