Microstructured separation device for separating parts of a liquid which comprises liquid components and at least one type of particle and/or at least one complex of interconnected particles of at least one type, with the following features: - the device comprises an inlet for the liquid, a collection section, and a transport path from the inlet to the collection section; - the transport path comprises, situated one after the other in the direction of transport, a first separation section for holding back at least some of the complexes and/or for slowing down the movement of at least some of the complexes and/or at least some of the particles, and a second separation section for holding back at least some of the complexes and/or at least some of the particles and/or for slowing down the movement of the particles; - the first separation section and second separation section have a microstructure with one or more microstructure elements - the transport path also comprises a resuspension section and an incubation section, - at least one substance for producing the complexes from particles and/or for promoting the production of the complexes from the particles is arranged in the resuspension section - the incubation section is suitable and intended to give the at least one substance received in the resuspension section the possibility of contributing to the formation of the complexes before the liquid reaches the first separation section, and - by means of the design of the incubation section, in particular the cross-sectional surface, length, configuration and/or surface properties of the incubation section, the flow speed and the dwell time of the liquid in the incubation section is set in a reproducible manner, characterized in that - the microstructure elements of the first separation section have pockets open in the direction of the inlet and/or the microstructure elements at least in part enclose, together with boundary surfaces of the transport path adjacent to the microstructure elements, pockets open in the direction of the inlet, - the microstructure elements of the first separation section delimit one or more first through-openings which have geometric dimensions allowing the particles and the complexes to pass through, - the microstructure elements of the second separation section delimit one or more first through-openings which have geometric dimensions allowing the particles and the complexes to pass through, and - the microstructure elements of the first separation section delimit second through-openings which have geometric dimensions allowing only the particles or particles of certain types to pass through, - wherein the width of the first through-openings and/or second through-openings is from 1 μm to 500 μm. - the device comprises an inlet for the liquid, a collection section, and a transport path from the inlet to the collection section; - the transport path comprises, situated one after the other in the direction of transport, a first separation section for holding back at least some of the complexes and/or for slowing down the movement of at least some of the complexes and/or at least some of the particles, and a second separation section for holding back at least some of the complexes and/or at least some of the particles and/or for slowing down the movement of the particles; - the first separation section and second separation section have a microstructure with one or more microstructure elements - the transport path also comprises a resuspension section and an incubation section, - at least one substance for producing the complexes from particles and/or for promoting the production of the complexes from the particles is arranged in the resuspension section - the incubation section is suitable and intended to give the at least one substance received in the resuspension section the possibility of contributing to the formation of the complexes before the liquid reaches the first separation section, and - by means of the design of the incubation section, in particular the cross-sectional surface, length, configuration and/or surface properties of the incubation section, the flow speed and the dwell time of the liquid in the incubation section is set in a reproducible manner, - the microstructure elements of the first separation section have pockets open in the direction of the inlet and/or the microstructure elements at least in part enclose, together with boundary surfaces of the transport path adjacent to the microstructure elements, pockets open in the direction of the inlet, - the microstructure elements of the first separation section delimit one or more first through-openings which have geometric dimensions allowing the particles and the complexes to pass through, - the microstructure elements of the second separation section delimit one or more first through-openings which have geometric dimensions allowing the particles and the complexes to pass through, and - the microstructure elements of the first separation section delimit second through-openings which have geometric dimensions allowing only the particles or particles of certain types to pass through, - wherein the width of the first through-openings and/or second through-openings is from 1 μm to 500 μm.