Normal and pathological erythrocytes studied by atomic force microscopy

Erythrocytes (red blood cells, RBCs) are the most common type of blood cells in vertebrates. Many diseases and dysfunctions directly affect their structure and function. Employing the atomic force microscope (AFM) physical, chemical, and biological/physiological properties of RBCs can be studied even under near-physiological conditions. In this chapter, we present the application of different AFM techniques to investigate and compare normal and pathological RBCs. We give a detailed description for nondestructive immobilization of whole intact RBCs and explain preparation techniques for isolated native RBC membranes. High-resolution imaging of morphological details and pathological differences are demonstrated with healthy and systemic lupus erythematosus (SLE) erythrocytes revealing substructural changes due to SLE. We also present the technique of simultaneous topography and recognition imaging, which was used to map the distribution of cystic fibrosis transmembrane conductance regulator sites on erythrocyte membranes in healthy and cystic fibrosis-positive RBCs.