Ultrastructural changes of erythrocyte membranes isolated with colloidal silica solution (Ludox)

The surface morphology of membrane fractions of human erythrocytes isolated by gradient centrifugation with a colloidal silica solution (Ludox) differed from the structure of control membranes isolated without the silica solution. The altered surface had a wrinkled appearance with a granular texture, compared with the smooth appearance of the controls. Thus the colloidal silica solution changed the ultrastructure of erythrocyte membranes. Possible mechanisms for the influence of the silica particles are suggested: secondary chemical bonds, e.g. hydrogen bonds, might well have been established between the silica particles and components of the erythrocyte membrane like spectrin of the inner surface of the membrane. Less probable is an attachment to positive sites of the outer side of the membranes as well as any association to the pitlike infoldings of the erythrocyte surface.