Figure 2: AFM elasticity maps of freshly prepared sections of gut embedded in agarose gels.
From: How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration
(a) Scheme of the experimental setup. The AFM cantilever (image courtesy of W.Roos) indents a transverse section of gut (mes: mesenchyme, ep: epithelium) embedded in an agarose (ag) gel along the Z direction. After each indentation, the cantilever is displaced in the XY plane to generate stiffness maps. (b) Mean mesenchyme stiffness deduced from AFM maps at the jejunum (E4.5–E5, n = 4 different guts) and hindgut (E8, n = 4 different guts) colonization stages. For each gut section, the mesenchyme stiffness was calculated by averaging over 2–5 100 × 100 μm2 maps, and each map comprises ~50–400 pixels (each pixel yields one local modulus value). Error bar length is the standard deviation across samples. A star indicates a significant difference (p < 0.05, two-tailed Mann-Whitney test). (c) E4-JE, E7-CA (caecum) and E8-HG are sections at stages during ENCC colonization. E8-JE corresponds to a region that has already been colonized by ENCCs. Each AFM map is a 100 × 100 μm square, typically with a 5 μm step (i.e., 20 × 20 px). Up to six maps were obtained per sample.The white region on AFM maps located around the gut sections corresponds to the stiff agarose gel in which the sample is embedded. (d) Post-AFM NC1 immunostaining of E8-HG and E8-JE sections showed the ENCCs to be located at the outer periphery of the gut. The dark region at the top of these images results from incorrect placement of the microscope diaphragm.
