Fig. 1. Principle of the single-cell electro-mechanical shear flow deformability cytometer.

a Principle of the electro-mechanical cytometer. Cells suspended in a viscoelastic buffer flow along a microfluidic channel within which there are two sets of microelectrodes. One set measures the cell volume (Z₁) whilst the second set measures cell deformation along the direction of flow (Z₂). Cells are focused into the centre of the channel by the viscoelastic suspending fluid that is used to create the shear stress. b shows the shear stress on an undeformed sphere in a viscoelastic fluid (0.5% w/v methyl cellulose, 0.015 Pa·s, density 1005 kg/m³, flow rate 10 µl/min, particle radius 6 µm), see ESI for further details. Arrows indicate direction of the local force. Density plots of electrical deformability (c) and electrical opacity (d) as a function of electrical diameter for HL60 cells (n = 2000) at a flow rate of 10 μl/min. 5 µm rigid beads included as reference particles in both cases