Absorbent microstructure panels are described herein. An example filter device includes a plurality of microstructure panels each having a front surface and a back surface, and a plurality of capillary ridges protruding from the front surface. The plurality of capillary ridges are each spaced apart from one another. The plurality of microstructure panels form an absorbent microstructure array by layering the plurality of microstructure panels together such that the plurality of capillary ridges of one microstructure panel contacts the back surface of an adjacent microstructure panel to create capillary tubes that draw fluid into the absorbent microstructure array.