Abstract: The invention relates to a microfluidic sensor which comprises a planar base sensor and a structured polymer film. The underside of the film, which faces the base sensor, comprises varyingly recessed geometric shapings and compartments which are produced, for example photolithographically, in micro injection molding, thermoforming or hot stamping processes. The microfluidic sensor according to the invention is particularly suitable for the production of biosensors in the form of single-use enzyme and affinity sensors, wherein the recessed geometries form sample collection, sample processing, incubation, buffer, mixing, reaction, reagent deposit, measurement, waste and aeration chambers, and distributing and/or connecting ducts, of which the outer peripheral contours are configured as narrow peripheral wall webs at the zero plane of the film and with a width between 50 ?m and 500 ?m; to which a recessed face or subsequent peripheral joining assembly with a spacing from 0.1 mm to 1.0 mm is outwardly attached.