Abstract: The micropump (11) has at least two first plate-forming means (10, 12) together defining a pump chamber (9), and the filter comprises liquid feed means, liquid collection means, second plate-forming means (10), and silicon plate-forming means (12; 15), said second plate-forming means (10) and said silicon plate-forming means (12; 15) facing each other and forming between them a cavity (13) for receiving a liquid, the cavity being partially closed by at least one transverse partition (20; 20') whose height is less than the depth of the cavity (13) and which separates it into an upstream portion and a downstream portion. Said silicon plate-forming means (12; 15) are fixed at least partially in leakproof manner to said second plate-forming means (10), the downstream portion of the cavity (13) communicates with said pump chamber (9), and the assembly comprising all of the plate-forming means (10, 12) constitutes a sandwich structure.