Figure 2.

From resistance to flow. The electrical resistance of the FluidFM channel with an attached bead was measured and the leak flow was calculated via simulations. (A) A nanometric average gap due to the contact roughness between bead and cantilever allowed the buffer solution to conduct electrical current between inside and outside (B, triangles). By analyzing the occurring electric and hydrodynamic resistance in a FEM model, the measured electric resistance could be converted into a corresponding volumetric flow (B, circles).