A scanning micro-fluid device for an exchange of species with a surface and with an intermediate immersion liquid is disclosed. The device comprises a first and a second micro-channel comprising a fluid. The first micro-channel comprises a first aperture and the second micro-channel comprises a second aperture. They have a distance to each other in an apex area in proximity of the surface of a substrate. The surface, the apex area is immersed with the intermediate immersion liquid. The device also comprises a first electrode reaching into the fluid on the first micro-channel and a second electrode reaching into the fluid on the second micro-channel, and an apex electrode. Different voltage levels are applicable to the first, the second and the apex electrode such that species are interacting at surface of the substrate.