A functional cassette for the detection of ligands comprises a first inner housing, a second middle housing and a third outer housing and each housing is at least partially rotatable relative to an adjoining housing. The first inner housing contains a central well adapted for receiving a sample, and the central well is in selectable fluid communication with at least one mixing chambers. The mixing chambers contain a reagent for forming a complex with a ligand. The first inner housing additionally comprises at least one compartments for the storage of a liquid crystalline material, and the compartments are in selectable fluid communication with at least one mixing chambers. The third outer housing comprises at least one detection chambers for observing the light transmission properties of a liquid crystal material and the detection chambers are in selectable fluid communication with the mixing.