Figure 7.

Test of diffusion inside the three-channel microfluidic chip. (a) The low-resolution mold for three large channels was made by CNC micromilling (outer channels marked with red lines, central filled with fluorescein in (b), the micromold of the smallest connecting microchannels was microfabricated by 2-photon polymerization. (b) The channels were first filled with IPA and at time zero, a droplet of fluorescein was deposited at the inlet of the central channel. (c) After 19 s, without flow, the fluorescein started to diffuse towards the lateral channels through the connecting microchannels. (d) 5 min later, the fluorescein was visible inside the lateral external channels (d). Scale bars are all 800 µm.