Fig. 4.

Mechanical characteristics of the leukocyte–endothelial interface. PMNs were added to bEND5 endothelial cells grown on filter membrane, fixed, and investigated in PBS. a AFM was used as a mechanosensor gently stitching down into the sample in an array of 64 × 64 points, yielding 4,096 force distance curves. From these, maps of b and c, d and e height sample elasticity can be calculated. Note that, in height images, the high regions are given in white, whereas in elasticity maps, bright coloring represents stiff regions. b The clearly elevated leukocyte is d considerably softer (darker) than the surrounding endothelium. After nanomanipulation procedure as in Fig. 3, the repeated force volume analysis of the same spot demonstrates c the loss of the leukocyte and e a homogeneous elasticity without clear differences at the interfacial area (green circle in d and e)