One or more embodiments of the present invention are directed to a vertical microfluidic probe head, which comprises a middle layer of material and two outer layers. The middle layer comprises two opposite, main surfaces, 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 opposite main surfaces. The middle layer is furthermore arranged between the two outer layers, which (at least partly) close the microchannel cavities grooved on the two main surfaces. This way, two sets of n microchannels are formed, which are, each, open on the edge surface, such that two opposite sets of n orifices are formed on the edge surface. Thus, the length of the apertures is not limited by the thickness of the middle layer.