Cell adhesion onto highly curved surfaces: one-step immobilization of human erythrocyte membranes on silica beads.

This paper deals with single-step, orientation-selective immobilization of human erythrocyte membranes on bare silica beads with different topographies: 1) solid (nonporous) silica beads with a diameter of 3 microns and 2) porous silica beads with a diameter of 5 microns. Erythrocyte membranes were immobilized onto beads simply by incubation, without sonication or osmotic lysis. Membrane orientation before and after immobilization was identified with two immunofluorescence labels: 1) the extracellular part of glycophorin can be labeled with a first monoclonal antibody and a second polyclonal antibody with fluorescence dyes (outside label), while 2) the cytoplasmic domain of Band 3 can be recognized with a first monoclonal antibody and a second fluorescent polyclonal antibody (inside label). Adherent erythrocytes on the beads all ruptured, inverted the asymmetric orientation of the membrane, and selectively exposed their cytoplasmic domain. The surface topography did not influence the orientation or the amount of immobilized membrane. On the other hand, the fact that no adsorption or rupture of erythrocytes could be observed on planar quartz substrates suggests a significant influence of contact curvature on adhesion energy.