Figure 1.

(a) Isolation procedure for highly matured BMs. MCF10A spheres were isolated from the EHS matrix and transferred on a poly-L-lysine-treated petri dish, then the membrane was peeled off, breaking the spheres apart with bent microcapillaries. (a) CellTracker cytoplasmic staining is shown in cyan. (b) Collagen IV staining is shown in green. (c) A phase-contrast image of the isolated BM fragments and (d) corresponding collagen IV staining. Only parts of the membrane lying flat and not folded on the surface were used for AFM imaging. (e) A phase-contrast light microscopy image of a low-matured isolated BM in ultrapure water. Overlapping AFM topographical images recorded in contact mode are shown in brown.