Abstract: Embodiments of the invention relate to devices for assaying a biomolecule from a plant sample including: a microfluidic cartridge for assaying a biomolecule from a plant sample, including: a top layer; and a bottom layer spaced apart from the top layer in a generally parallel orientation with respect to the top layer, the bottom layer defining a plurality of wells therein that protrude from a surface of the bottom layer; and a filter module for filtering the plant sample, including a filter body defining: an upper portion including an inlet structure forming an inlet channel; and a bottom portion configured to accept and secure a filter membrane. The filter body is configured to accept a microvolume aliquot of the plant sample, the bottom structure includes an outlet structure forming an outlet channel on an outlet side of the filter membrane, and at least one of the plurality of wells includes an assay reagent solution.