Packaging of microfluidic devices

A microfluidic device for analysis of biological samples having a shelf life extended by limiting moisture transfer comprising:

• (a) a base layer containing chambers containing dried reagents and interconnected by capillary passageways;
• (b) a top layer over said base layer for enclosing at least some of said chambers containing dried reagents and interconnected capillary passageways;
• (c) an adhesive disposed between said base layer and said top layer for securing said top layer to said base layer;
• said base layer and said top layer each being of a material having a thickness capable of limiting the transmission of moisture through said base and top layers to less than 0.01 g/m2-day thereby assuring that no more than 0.01 mg of water will be added for each mg of dry reagent over the life of the device, wherein said base layer is of at least one member of the group consisting of polystyrene, polyalkylene, polyolefins, epoxies, PTFE, PET, chloro-fluoroethylenes, polyvinylidene fluoride, PE-TFE, PE-CTFE, polyester, polymethylpentene, polyphenylene sulfide, and PVC and said top layer is of at least one member of the group consisting of polypropylene, PET, polyethylene, polyolefin, polyester, polystyrene and multi-layer materials including PCTFE, PVC, and LPC with polyester, polyolefin or polyamide, and wherein said base and top layers each have a thickness limiting transfer of moisture to less than 0.01 g/m2-day;
• and
• (d) adhesive covers disposed over chambers containing dried reagents not enclosed by said top layer of (b), thereby enclosing all chambers containing dried reagents.