Liquid transfer devices

A device for performing biochemical diagnostic assays, said device comprising:

• a plurality of test units, each test unit comprising
• first and second liquid flow channels of porous material leading from respective first and second channel ends to a common site, said first and second channel ends being disposed in substantially the same plane for simultaneous application of a liquid thereto, said second flow channel further extending from said common site to a sample binding site having an analyte binding reagent fixed thereto, said first and second liquid flow channels each having respective face and edge surfaces;
• and
• a liquid impermeable barrier in contact with said face surfaces of said first and second liquid flow channels, said impermeable barrier and said first and second liquid flow channels forming an assembly of superposed face-to-face-layers, said barrier separating said first and second liquid flow channels from direct contact of said face surfaces except for at said common site over which said face surfaces of said first and second liquid flow channels are in fixed engagement with each other for liquid flow therebetween, a first reagent releasably bound to said second flow channel between said sample binding site and said common site and a second reagent releasably bound to said second flow channel between said second channel end and said sample binding site said channels being operable to transfer liquid by capillary flow to said common site in sequentially timed manner following simultaneous application of the liquid to said first and second channel ends and thereby transfer said first and second reagents in sequentially timed manner to said sample binding site;
• wherein said plurality of test units are formed by providing a plurality of said first channels in a first integral layer of said porous material and a plurality of said second channels in a second integral layer of said porous material.