To create a small, portable, fully automated biosensor, a compact means of
fluid handling is required. We designed, manufactured, and tested a "fluidi
cs cube" for such a purpose. This cube, made of thermoplastic, contains res
ervoirs and channels for liquid samples and reagents and operates without t
he use of any internal valves or meters; it is a passive fluid circuit that
relies on pressure relief vents to control fluid movement. We demonstrate
the ability of pressure relief vents to control fluid movement and show how
to simply manufacture or modify the cube. Combined with the planar array b
iosensor developed at the Naval Research Laboratory, it brings us one step
closer to realizing our goal of a handheld biosensor capable of analyzing m
ultiple samples for multiple analytes.