Vertical microfluidic probe head with large scale surface processing apertures

A method for processing a surface with a vertical microfluidic probe head having

• a middle layer of material;
• two outer layers, wherein each of the middle layer and the two outer layers are distinct from each other;
• wherein the middle layer comprises two opposite, main surfaces, a first main surface and a second main surface, which are, each, grooved up to a same edge surface that adjoins each of the main surfaces, so as to form two sets of n microchannel cavities, n≥1, on each of the main surfaces wherein a first set of the n microchannel cavities on the first main surface is not in fluidic communication with a second set of the n microchannel cavities on the second main surface except at the same edge surface;
• and
• wherein the middle is arranged between the two outer layers, the latter at least partly closing the microchannel cavities grooved on the two main surfaces, so as to form two sets of n microchannels that are, each, open on the edge surface, such that two opposite sets of n orifices are formed on the edge surface, the method comprising:
• positioning the microfluidic probe head so as for the edge surface to face a surface to be processed;
• dispensing processing liquid via each orifice of a first one of the sets of n orifices, so as for the dispensed processing liquid to process the surface;
• and
• aspirating liquid via each orifice of a second one of the sets of n orifices.