Fig. 5: Proof-of-concept towards all-in-one fluidic testing devices.

a Thanks to its simple geometry, the device may be easily scaled down and plasma treated to swiftly capture a small fraction of a water drop. The initial open state enables a fast flow through the grooves, and the closing of the structure impedes evaporation and unwanted exchanges with the environment (h = w = d = 300 ± 30 μm, e = 60 ± 5 μm). Additional treatment with serum albumin enables long-lasting hydrophilicity and the capture of blood (right panel, see ‘Methods’ section ‘Surface treatment of the elastomer'). b Each groove may be additionally functionalised with specific markers (here, dye) using e.g. evaporation. Stretching the device, and using the strong adhesion on glass, the grooves may be made transitorily larger to ease this step. When dipped in a fluid (here, ethanol), the device swiftly samples and aliquots the liquid in each groove, where it efficiently reacts with the specific marker thanks to the triangular groove cross-section that ensures a large surface-to-volume ratio. The device is then put in contact with an absorbent textile, inducing the radial spreading of the captured liquid, enabling a direct reading of the role of the different markers. Source data are provided as a Source Data file.