Figure 2.

Microfluidic device, data processing, and analysis

(A) Top-view schematics of the microfluidic device made of polydimethylsiloxane (PDMS). Inlets (1) and (3) are used for injecting buffer solutions while cells are injected through inlet (2). Controlled pressure drop is applied between inlets and outlet to push cells through constrictions.

(B) Zoomed 3D view of the constriction zone, with two different heights: h₂ for the main 300-μm wide channel and h₁ for the constrictions (length l, width w). l = 100 μm, w = h₁ = 6 μm, h₂ = 10 μm. The low-height region is 500 μm long in total, including the constrictions.

(C) Typical time evolution of the cell tongue length l(t). The curve is analyzed using two methods: i) It is decomposed into three linear parts, of slopes S_I to S_III, which correspond to the cell entry time T_e; ii) The first two parts of the curve are fitted (in red) using a rheological model which combines a Kelvin–Voigt solid (a spring of constant E₁ in parallel with a dashpot of viscosity η₁) in series with a dashpot of viscosity η₂ (see inset).

(D) Time-lapse of a 24-μm cell entering a constriction of width w. Scale bar: 15 μm.