Figure 8.

Cumulative histograms of the distance distribution for n=5–15 HEK cells grown on smooth surfaces with different protein coatings. In all cases, 10–20% of the attached membrane showed close adhesion with distances of d_j≤10 nm. By fitting the histograms for the cells on polylysine-coated surfaces to Gaussians (a–c, black curves), we obtained average cleft distances of ${\overline{d}}_j=37\text{nm}$ (PLL), 41 nm (PDL) and 33 nm (ECM). For the other substrate coatings (d–g) we found no comparable distance distribution.