Abstract: This invention provides microfabricated systems for extraction of desired particles from a sample stream containing desired and undesired particles. The sample stream is placed in laminar flow contact with an extraction stream under conditions in which inertial effects are negligible. The contact between the two streams is maintained for a sufficient period of time to allow differential transport of the desired particles from the sample stream into the extraction stream. In a preferred embodiment the differential transport mechanism is diffusion. The extraction system of this invention coupled to a microfabricated diffusion-based mixing device and/or sensing means allows picoliter quantities of fluid to be processed or analyzed on devices no larger than silicon wafers. Such diffusion-based mixing or sensing devices are preferably channel cell systems for detecting the presence and/or measuring the quantity of analyte particles in a sample stream.

Abstract: This invention provides a method by which the performance of reciprocating NMPV (No-Moving-Parts-Valve) micropumps can be optimized for a given choice of valve design, e.g. for diffuser/nozzle valves, rectifier valves etc. The method can more generally be used to design and produce NMPV micropumps with structures optimized for maximal pump performance. The method can further be used to design and construct NMPV pumps significantly smaller in size than those currently available to the art without significant loss in pump performance.

Abstract: A method and apparatus including programmed computers are provided for determining the viscosity of a first stream in a laminar flow and a second stream in a laminar flow, the flow rates, the centerline of the flow channel, and the position of the interface between the streams with respect to the centerline, and for calculating viscosity ratio of the first stream to the second.

Abstract: Methods and apparatuses including programmed computers are provided for determining the initial concentration of diffusible particles in a sample stream introduced into a system wherein the sample stream which contains the diffusible particles flows in adjacent laminar flow with an indicator stream containing an indicator substance capable of exhibiting an observable change at a known concentration of the diffusible particles.

Abstract: This invention provides a microfabricated extraction system and methods for extracting desired particles from a sample stream containing desired and undesired particles. The sample stream is placed in laminar flow contact with an extraction stream under conditions in which inertial effects are negligible. The contact between the two streams is maintained for a sufficient period of time to allow differential transport of the desired particles from the sample stream into the extraction stream. In a preferred embodiment the differential transport mechanism is diffusion. The extraction system of this invention coupled to a microfabricated diffusion-based mixing device and/or sensing device allows picoliter quantities of fluid to be processed or analyzed on devices no larger than silicon wafers.

Abstract: Micropumps fabricated by micromachining techniques and employing fixed or no-moving-parts valves. As one aspect of the invention, a laser-assisted chemical etching technique is employed for providing smooth-walled, curved configuration necessary to obtain the desired flow characteristics of the valves that are used in conjunction with the micropump.