High-throughput Cellulose based Pulldown Assay

There is provided an apparatus for a cellulose-based vertical flow assay, the apparatus comprising: a holder for supporting a cellulose substrate having a plurality of test zones thereon, the holder having a base plate and engaging members; and a lid for reversibly engaging with the engaging members of the holder such that when engaged, the lid is disposed over the base plate and a gap exists between the lid and the base plate, wherein the lid comprises a plurality of openings for allowing access to the test zones on the cellulose substrate. Also provided are related methods.