A filling apparatus for filling a microplate. The microplate can comprise a plurality of wells each sized to receive an assay. A substrate can comprise a first surface and an opposing second surface, a first assay input port for receiving the assay disposed on the first surface, a plurality of staging capillaries extending through the substrate, and a first plurality of microfluidic channels fluidly coupling the first assay input port with at least one of the plurality of staging capillaries. Each of the plurality of staging capillaries can comprise an inlet and an outlet and be sized to receive the assay.