A mixing device for operating biological, chemical or biochemical materials used in an assay includes a mixing member formed with a plurality of chambers, each having a sealable port provided along an edge of the mixing member. The mixing device also includes one or more compartments that are movable along the edge of the mixing member between selected ones of the sealed chambers. This compartment is operable to receive materials from and transfer materials between the chambers. Selected ones of the chambers include associated processing elements, for example, including heating and cooling elements, magnetic elements, membranes and lateral flow devices. The mixing device is also pivotable, for example, to facilitate the application of gravity force in the transfer of materials between the chambers and one or more compartments. The mixing device may operate manually by hand-held unit. Also, this mixing device may operate automatically with at least one driving unit.