Abstract: Described herein is microfluidic device for joining fluids and a related method for doing the same. The device according to the present invention includes a microfluidic junction, an outlet channel, and a plurality of circuit units. A microfluidic junction is an area for converging multiple fluids. An outlet channel is capable of receiving fluid from the microfluidic junction. An outlet channel includes a first end connected with the microfluidic junction, a second end connected with a waste reservoir, and an analysis region positioned between the first end and the second end of the outlet channel. The device also includes a plurality of circuit units.

Abstract: An apparatus is provided for testing fluid samples includes a sensor, which can be light source, directed to a flow cell and a photo sensor for detecting a light beam reflected from the flow cell. The photo sensor monitors the fluid in the flow cell by sensing the reflected light beam from the flow cell, thereby monitoring the test.

Abstract: Microfluidic devices and systems for affecting the serial to parallel conversion of materials introduced into the device or system. Material or materials to be converted from a serial orientation, e.g., a single channel, into a parallel orientation, e.g., multiple channels, are introduced into an open chamber or field in which containing flows of materials maintain the cohesiveness of the sample material plugs serially introduced into the open chamber. The sample material or materials are then redirected in the chamber toward and into a plurality of parallel channels that also communicate with the chamber.

Abstract: A flow-through monitor for detecting molecular contamination (MC) within a fluid flow. The monitor has a diffusion chamber having an inlet port and an outlet port, and a structure for supporting a fluid flow from the inlet port to the outlet port. The structure includes a flow gap causing a diffusion of molecular contaminants into the diffusion chamber, while substantially preventing, for a rate of the fluid flow above a predetermined magnitude, particulate contaminants within the fluid from entering the diffusion chamber. A SAW device detects molecular contamination interior to the diffusion chamber. Fluid input to the flow-through monitor may be diluted by a pure fluid for extended monitor life. A system for aggregate sampling connects an ensemble manifold upstream of the flow-through monitor. A system for triggered sampling connects a sample preconcentrator downstream of the flow-through monitor. A chemically selective membrane may be located between the flow gap and the SAW.

Abstract: A biological material detection apparatus which detects a charged biological material such as a gene or protein contained in a sample liquid is disclosed. A biological material detection element includes a substrate, at least one first electrode formed on the substrate, and a plurality of second electrodes which are arrayed at predetermined intervals around the first electrode on the substrate along the circumferential direction and to which ligands that react with predetermined biological materials are respectively immobilized. A sample liquid is introduced toward the first electrode on the substrate. The introduced sample liquid is moved radially toward the second electrodes by electrical control.

Abstract: An apparatus is provided for testing fluid samples includes a sensor, which can be light source, directed to a flow cell and a photo sensor for detecting a light beam reflected from the flow cell. The photo sensor monitors the fluid in the flow cell by sensing the reflected light beam from the flow cell, thereby monitoring the test process. The apparatus may have additional light source so that the photo sensor may monitor the test process by detecting the absorption light beam or fluorescent light beam from the flow cell at different phases of the test process.

Abstract: A method is provided of obtaining a sample concentration of a solution in a microfluidic device. The microfluidic device includes a channel having a reservoir and a collection port. The channel is filled with a solution having particles therein. A reservoir drop is deposited over the reservoir of the channel such that the solution of the channel flows towards the collection port in response to evaporation of the solution at the collection port. The particles at the collection port are collected to obtain the sample concentration.

Abstract: An apparatus is provided for testing fluid samples includes a sensor, which can be light source, directed to a flow cell and a photo sensor for detecting a light beam reflected from the flow cell. The photo sensor monitors the fluid in the flow cell by sensing the reflected light beam from the flow cell, thereby monitoring the test.

Abstract: A method is provided for pumping fluid through a channel of a microfluidic device. The channel has an input port of a predetermined radius and an output port of a predetermined radius. The channel is filled with fluid and a pressure gradient is generated between the fluid between the input port and the fluid at the output port. As a result, fluid flows through the channel towards the output port.

Abstract: A fluid interface port in a microfluidic system and a method of forming the fluid interface port is provided. The fluid interface port comprises an opening formed in the side wall of a microchannel sized and dimensioned to form a virtual wall when the microchannel is filled with a first liquid. The fluid interface port is utilized to fill the microchannel with a first liquid, to introduce a second liquid into the first liquid and to eject fluid from the microchannel.

Abstract: A method is disclosed for determining the concentration of trivalent chromium Cr(III) in a sample. The addition of perchloric acid has been found to increase the atomic chromium spectrometric signal due to Cr(III), while leaving the signal due to hexavalent chromium Cr(VI) unchanged. This enables determination of the Cr(III) concentration without pre-concentration or pre-separation from chromium of other valences. The Cr(III) concentration may be measured using atomic absorption spectrometry, atomic emission spectrometry or atomic fluorescence spectrometry.

Abstract: This invention provides methods for using liquid junction potentials to control the transport of charged particles in fluid streams that are in laminar flow within microfluidic channels. Applications of the methods of this invention include sample preconditioning (removal of interfering substances), electrophoretic separation (fractionation) of charged particles, enhanced or delayed mixing of charged particles across a fluid interface relative to diffusion only, focusing charged particles in a fluid stream in one or two dimensions, and concentration of charged reactants at a fluid interface.

Abstract: A method is provided for performing a gradient-based assay in a microfluidic device. The method includes the steps of passing first and second fluids through a channel in the microfluidic device. The first fluid has a predetermined concentration of particles therein such that the particles in the first fluid diffuse into the second fluid so as to cause a gradient of concentration of particles in the second fluid as the second fluid flows through the channel. The second fluid sequentially intersects a series of targets along the channel wall as the second fluid flows through the channel.

Abstract: Taste recognition is performed by letting a solvent flow through a holding section which holds an object to be recognized and measuring the solvent which has flowed through the holding section by a taste sensor. If the flow rate of the solvent is set at about 1 ml/min, the solvent whose quantity is almost equal to that of saliva secreted in a mouth can be supplied to the object to be recognized, and hence the taste recognition can be performed by the taste sensor.

Abstract: This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.

Abstract: A multiple port valve integrated with the function of the sample shut off valve is disclosed. The integration of the sample shut off function eliminates extra plumbing and labor costs associated with a separate sample shut off valve. Additionally, the multiple port valve integrated with the function of the sample shut off valve provides a shorter equilibration time and less tubing volume.

Abstract: A method of operating an analytical flow cell device comprising an elongate flow cell having a first end and a second end, at least two ports at the first end and at least one port at the second end, comprises introducing a laminar flow of a first fluid at the first end of the flow cell, and a laminar counter flow of a second fluid at the second end. Each fluid flow is discharged at the first end or the second end, and the position of the interface between the first and second fluids in the longitudinal direction of the flow cell is adjusted by controlling the relative flow rates of the first and second fluids. Also disclosed are a method of analyzing a fluid sample for an analyte, a method of sensitizing a sensing surface, and a method of contacting a sensing surface with a test fluid.

Abstract: A reconfigurable modular microfluidic system, providing a microfluidic breadboard platform for the formation of fluidic network and fluidic sealing upon a system assembly. Modular microfluidic elements or “chips” are arranged on a precisely machined alignment base to form a fluidic network, with fluid connections provided directly from chip-to-chip at overlapping corners. Fluidic access to external devices is possible at every fluid connection and through special ingress/egress chips. By maintaining a largely planar layout, optical access is provided for detecting or visualization for every chip. The assembly may be covered by a perforated cover plate.

Abstract: Microfluidic devices and methods are provided for enhancing detection of a diffusion pattern formed by particles diffusing between at least two fluid streams in parallel laminar flow such that an interface is formed between them by increasing the dimension of the streams in the diffusion direction. This may be accomplished by flowing the streams through a transforming turn, or by flowing the streams through a channel having diverging walls. Devices and methods are also provided for enhancing diffusion between two streams comprising changing the interface between said streams from a narrow interface to a broad interface.

Abstract: Array based fluid is stored in through holes that extend through a substrate. Combined capillary and hydrophyllic forces are used to retain the fluid and also transfer it to other substrates of similar type. In another embodiment vacuum and pressure forces are used to introduce the fluid and remove the fluid from the known through holes and transfer the remaining fluid to other substrates. In yet another embodiment, electrokinetic forces are used to retain and move the fluids across the substrates via the through holes. The substrates are aligned and the fluids are transferred or mixed based on the above techniques.

Abstract: The present invention provides microfluidic devices, systems and methods for using the same, which facilitate the introduction of fluid to and from a microfluidic channel located within the microfluidic devices.

Abstract: The movement and mixing of microdroplets through microchannels is described employing microscale devices, comprising microdroplet transport channels, reaction regions, electrophoresis modules, and radiation detectors. The discrete droplets are differentially heated and propelled through etched channels. Electronic components are fabricated on the same substrate material, allowing sensors and controlling circuitry to be incorporated in the same device.

Abstract: Improved sealing for microstructures in microfluidic devices having a plurality of units is provided by providing collars surrounding the openings to the microstructures, such as reservoirs. The collars are protrusions extending from the surface of the devices and the internal walls of the collars generally aligned with the internal walls of the microstructure. Conformable and/or adhesive lids are employed for sealing the microstructures.

Abstract: An injection pump assembly 10 in a chemical delivery system for simultaneously delivering reagents into a combinatorial reactor system having multiple injectors. The assembly 10 has a plurality of injectors 12, each injector 12 being in fluid communication with one of the multiple reactors. Each injector 12 has (1) a pump 14 in which a plunger 18 sealingly moves to ingest, store and discharge a flushing solvent 20; (2) a pipette assembly 22 for loading, storing, and discharging one or more reagents into one of the reactors in the combinatorial reactor system, first and second reservoirs for retaining some of the reagents; (3) one or more hollow needles 32, each for selectively delivering a reagent 24 to the first 28 or the second 24 reservoir; (4) a first valve 34 positioned downstream of the first 28 reservoir; and (5) a second valve 36 positioned downstream of the second 30 reservoir. When each valve 34, 36 is in a closed position, the reagents 24, 48 can be stored in isolation from each other.

Abstract: A chemical processing microsystem useful for identifying and optimizing materials (e.g., catalysts) that enhance chemical processes or for characterizing and/or optimizing chemical processes is disclosed. The chemical processing microsystem comprises a plurality of microreactors 600 and, in a preferred embodiment, a plurality of microseparators 900 integral with the chemical processing microsystem 10. The microreactors 600 are preferably diffusion-mixed microreactors formed in a plurality of laminae that include a modular, interchangeable candidate-material array 100. The material array 100 comprises a plurality of different candidate materials (e.g., catalysts), preferably arranged at separate, individually addressable portions of a substrate (e.g., wafer). The microseparators 900 are similarly formed in a plurality of laminae that include a modular, interchangeable adsorbent array 700.

Abstract: The present invention, provides a flow cytometry apparatus for the detection of particles from a plurality of samples comprising: means for moving a plurality of samples comprising particles from a plurality of respective source wells into a fluid flow stream; means for introducing a separation gas between each of the plurality of samples in the fluid flow stream; and means for selectively analyzing each of the plurality of samples for the particles. The present invention also provides a flow cytometry method employing such an apparatus.

Abstract: Items of mail are rapidly processed in a mail sampling system to determine if the mail is contaminated with a chemical or biological agent. The mail sampling system maintains a negative pressure in a containment chamber and includes a triggering sampler that makes a threshold determination regarding possible contamination, and a detecting sampler that obtains a sample for more detailed analysis in response to a signal from the triggering sampler. A sample of particulates collected from an item of mail is either removed for analysis or analyzed in the system to identify a contaminating agent. Optionally, the system includes an archiving sampler, which archives samples for subsequent processing and analysis, and a decontamination system, which is activated to decontaminate the mail if needed.

Abstract: The present invention, provides a flow cytometry apparatus for the detection of particles from a plurality of samples comprising: means for moving a plurality of samples comprising particles from a plurality of respective source wells into a fluid flow stream; means for introducing a separation gas between each of the plurality of samples in the fluid flow stream; and means for selectively analyzing each of the plurality of samples for the particles. The present invention also provides a flow cytometry method employing such an apparatus.

Abstract: A method and apparatus for controlling a stream of liquid and air segments wherein the liquid and air segments are selectively aspirated into a first fluid conduit in a plurality of cycles, each cycle beginning with the aspiration of a first air segment and ending with the aspiration of a final air segment. The liquid and air segments are then transferred from the first fluid conduit to a second fluid conduit. The volume of the final air segment of each cycle is then adjusted after the final air segment has moved into the second fluid conduit. Next, the liquid segments and the air segments of each cycle are transferred from the second fluid conduit to a third fluid conduit. The volume of the first air segment of each cycle is then adjusted after the first air segment has moved into the third fluid conduit.

Abstract: Flow rates in a microfluidic device are modulated after performing serial dilutions by flow reduction channels that draw fluid from the main channel, thus reducing the flow rate. The reduction in flow rate and/or use of smaller dimension channels allow reduced reagent consumption. In addition, multiple flow reduction channels are used for multiple concentration measurements and for performing multiple assays simultaneously on a single sample. Also included are microfluidic devices and integrated systems for performing assays using serial dilutions, single pressure sources, multiple concentration measurements, and reduced reagent consumption. Devices comprising flow reduction channels are also used to suppress pressure perturbations from spontaneous injection.

Abstract: The adsorption rate of proteins from solutions on surfaces in the region of interface layers is often so large that a depletion of the protein in the interface layer results. Due to this, the total reaction becomes transport-dependent, sensitively disrupting the determination of the rate constants. In known TIRF-analysis chambers or bio-sensor systems with a liquid interface layer of ˜10 ?m thickness and mass transport coefficients of 10?6-10?5 m/s it has up limitation. With the help of a TIRF-flow-through shear analyzer in which a certain volume unit of an immiscible fluid, for example an air bubble, is fed into the buffer flow, an ultra-thin liquid layer arises on the surface with a thickness of 100-200 nm, wherein interface surfaces below 10 nm thickness are technically possible.

Abstract: Disclosed herein is a microchip provided with a specimen flow pass, a reagent flow pass, a confluence flow pass all of which are fine flow passes. The specimen flow pass allows specimen to flow toward one end thereof. The reagent flow pass is connected to that end of the specimen flow pass and allows at least one reagent to flow for reaction with the specimen. The confluence flow pass extends from that end of the specimen flow pass and allows the confluent specimen and reagent to flow. A sensing portion is assigned near or at the confluence flow pass, and the reaction of the specimen and the reagent is capable of being detected or observed there. Further to this, the microchip comprises a force applying means for reciprocally moving the specimen and the reagent at the sensing portion.

Abstract: A flow of liquids is carried out on a microscale utilizing surface effects to guide the liquid on flow paths to maintain laminar flow. No sidewall confining structure is required, minimizing resistance to flow and allowing laminar flow to be maintained at high flow rates. The guiding structure has flow guiding stripes formed on one or both of facing base and cover surfaces which are wettable by a selected liquid to direct the liquid from a source location to a destination location. The regions adjacent to the guiding stripes on the base and cover surfaces are non-wettable. The smooth interface between the gas and liquid along the flowing stream allows gas-liquid reactions to take place as a function of diffusion across the interface without mixing of the gas and liquid. Liquid-liquid flows may also be guided with such structures.

Abstract: Non-planar microfluidic devices and methods for transferring fluids between vessels and microfluidic devices are provided. The devices may be contoured to physically contact non-planar vessels, such as pipes, tubes, vials, or syringes to establish fluid communication between a vessel and a microfluidic device. Devices according to the invention may be constructed from flexible, rigid, or combinations of flexible and rigid materials. In certain embodiments, microfluidic devices are composed of sandwiched stencils, and self-adhesive tapes may be used for one or more layers. A microfluidic device may be removably attached to a vessel with a non-permanent adhesive or adhesive layer. Continuously wrapped microfluidic devices fashioned from a single layer, in addition to rewindable microfluidic devices constructed from multiple layers, are provided. A multi-plunger syringe permits a microfluidic device or other reservoir coupled to the vessel to be filled on the draw stroke of the syringe plunger.

Abstract: An open capillary channel device for open tubular solid phase extraction of molecules capable of providing a tube enrichment factor of at least 1. The device comprises a channel having one end connected to a pump for pumping liquid and gas, and the other end can be connected to an interface for a protein chip sample applicator or a mass spectrometer, the inner surface of the channel being an extraction surface. The extraction surface can be bonded to an affinity binding agent. The affinity agent can be a chelated metal, a protein, a sugar or nucleic acid with a binding affinity for a selected analyte. The method using this device comprises binding sample molecules from a sample solution to the affinity extraction surface of the capillary channel; and desorbing a substantial portion of the sample molecules from the extraction surface with a desorbent liquid, with an extraction factor greater than 1.

Abstract: Apparatus for determining the ozone decay rate constant for an ozone-in-water solution. The apparatus includes a single ozone residual sensor, to which a sample flow is directed to measure the initial ozone residual concentration, and to which a delayed flow stream of the same solution is directed to measure the ozone residual concentration after passage of a particular time interval. The time delay of the flow stream is achieved by passing the flow stream through a chamber that includes a tubing coil through which the sample stream flows, after which the ozone residual concentration of the delayed sample stream is measured by the same ozone residual sensor. A portion of the incoming flow stream is diverted to flow through the chamber to maintain the delayed sample stream at substantially the same temperature as the incoming flow stream.

Abstract: An automated device that couples a pair of differently sized sample loops with a syringe pump and a source of degassed water. A fluid sample is mounted at an inlet port and delivered to the sample loops. A selected sample from the sample loops is diluted in the syringe pump with the degassed water and fed to a flow through detector for analysis. The sample inlet is also directly connected to the syringe pump to selectively perform analysis without dilution. The device is airtight and used to detect oxygen-sensitive species, such as dithionite in groundwater following a remedial injection to treat soil contamination.

Abstract: An apparatus provides for the detection, the determination of the location or the spatial distribution, and/or the quantification of an amount of a chemical species by allowing the chemical species to come into contact with a fluid medium contained in a permeable capillary, transferring the content of the capillary after the contact to a detector, and detecting the chemical species as the content of the capillary is transferred to a detector. The fluid medium can contain a selected reagent that selectively interacts with the chemical species to produce an optically detectable interaction product. The location and amount of the chemical species are determined from a characteristic of the chemical species or its interaction product measured on the content of the capillary and the time at which the characteristic is detected.

Abstract: A magnetohydrodynamic fluidic system includes a reagent source containing a reagent fluid and a sample source containing a sample fluid that includes a constituent. A reactor is operatively connected to the supply reagent source and the sample source. MHD pumps utilize a magnetohydrodynamic drive to move the reagent fluid and the sample fluid in a flow such that the reagent fluid and the sample fluid form an interface causing the constituent to be separated from the sample fluid.

Abstract: A method involving the automatic, online dilution of polymer and/or colloid solutions, such that, when the diluted polymer stream flows through suitable detectors, non-equilibrium processes, such as polymerization, degradation and aggregation, can be monitored. The dilution involves a reacting or stock solution of polymer and/or colloid, and at least one solvent. The online dilution technique can also be used to assess the effects of solvent quality and other solutes on polymer/colloid characteristics and reactions, and also permits equilibrium characterization of polymers/colloids by making a single stock solution of the polymer/colloid.

Abstract: An apparatus and a method for analyzing a plurality of samples according to an analysis protocol is described, wherein each of the samples is contained within a liquid test package comprising a plurality of liquid and air segments including a reagent segment and wherein during at least a portion of the protocol the reagent segment emits photons. At least one of the liquid test pack includes a buffer segment separated from the reagent segment by a vanish bubble. The apparatus comprises a fluid conduit through which the liquid test packages are flowed, a first luminometer positioned along the fluid conduit for detecting photons emitted by the reagent segment of the at least one of the liquid test packages, a second luminometer positioned along the fluid conduit for detecting photons emitted by the reagent segments of the liquid test packages other than the at least one of the liquid test packages, and a vanish zone contained within the fluid conduit between the first and second luminometers.

Abstract: Apparatus and method for sequential injection liquid-liquid extraction analysis. Under the control of a bidirectional precision pump, a stream-selection valve, and a microprocessor, a series of liquid zones is built up in a holding/mixing coil. The liquid zones are transferred from the holding/mixing coil to a separation cell. After phase separation into an extract and a raffinate, the extract is withdrawn from the separation cell and sent to a detector, which determines the amount of a component which was extracted from a sample by an extraction solvent. The principal advantages of this automated technology are elimination of the need for dynamic phase separation; on-line pre-extraction chemical conditioning; a substantial reduction in solvent, reagent, and sample usage; and a similar substantial reduction in waste generation.

Abstract: A reference T-sensor system is provided for detecting the presence and/or measuring the concentration of analyte particles in a sample stream. The system includes: a) a laminar flow channel; b) three or more inlets in fluid connection with the laminar flow channel for respectively conducting into the laminar flow channel (1) an indicator stream which may include an indicator substance which indicates the presence of analyte particles by a detectable change in property when contacted with the analyte particles, (2) the sample stream, and (3) a reference stream, which can be a control stream and/or an internal standard stream; c) wherein the laminar flow channel has a depth and/or width sufficiently small to allow laminar flow of the streams and a length sufficient to allow particles of the analyte to diffuse into the indicator stream to form a detection area; and (d) an outlet for conducting the streams out of the laminar flow channel preferably to form a single mixed stream.

Abstract: The present invention provides an apparatus and method for storing a particle-containing liquid. The storage apparatus comprises a microfluidic convoluted flow channel having a plurality of particle capture regions. The storage channel is preferably an isotropic spatially periodic channel. Sedimented particles can be resuspended following storage. This invention further provides a microfluidic analysis cartridge having a convoluted storage channel therein. The sample analysis can use optical, electrical, pressure sensitive, or flow sensitive detection. A plurality of analysis channels can be included in a single cartridge. The analysis channels can be joined to reagent inlets for diluents, indicators or lysing agents. A mixing channel can be positioned between the reagent inlet and the analysis region to allow mixing and reaction of the reagent. The cartridge can include additional valves and pumps for flow management.

Abstract: Methods and apparatuses are provided for determining presence and concentration of analytes by exploiting molecular binding reactions and differential diffusion rates. Analyte particles and binding particles are allowed to diffuse toward each other, and slowing of the diffusion front is detected when they meet. From the position of the diffusion front, presence and concentration of analyte particles can be determined. One embodiment provides a competitive immunoassay in a microfluidic format. This diffusion immunoassay (DIA) relies on measuring the concentration of labeled antigen along one dimension of a microchannel after allowing it to diffuse for a short time into a region containing specific antibodies. A simple microfluidic device, the T-Sensor, was used to implement a DIA to measure the concentration of phenytoin, a small drug molecule. Concentrations of analyte over the range of 50 to 1600 nM can be measured in less than a minute.

Abstract: A method for conducting a broad range of biochemical analyses or manipulations on a series of nano- to subnanoliter reaction volumes and an apparatus for carrying out the same are disclosed. The method and apparatus are implemented on a fluidic microchip to provide high serial throughput. The method and device of the invention also lend themselves to multiple parallel analyses and manipulation to provide greater throughput for the generation of biochemical information. In particular, the disclosed device is a microfabricated channel device that can manipulate nanoliter or subnanoliter biochemical reaction volumes in a controlled manner to produce results at rates of 1 to 10 Hz per channel. The individual reaction volumes are manipulated in serial fashion analogous to a digital shift register.

Abstract: Provided is a sample clean-up apparatus for removing low-molecular weight substances such as salts from high-molecular weight biological samples such as proteins by simple molecular diffusion in a laminar flow channel and enabling solvent exchange for samples to be suitable for mass spectrometry.

Abstract: The liquid sample take-up device comprises two layers of concentric tubing. An outer tube has a fluid take-up end for selective immersion in a liquid to be sampled, and a liquid connection spaced from the fluid take-up end adapted to receive a chemical reagent under pressure, creating a reagent flow toward the take-up end. An inner tube is disposed within the outer tube and has an open end adjacent to the outer tube take-up end. The inner tube is adapted to fluid connect to a negative pressure source, higher than the reagent pressure, to create a fluid flow within the inner tube in a direction away from the open end, whereby sampled liquid and reagent are mixed adjacent the inner tube open end and within the outer tube take-up end. When the outer tube take-up end is not immersed in a liquid to be sampled, air is drawn into the outer tube take-up end and into the inner tube open end, creating a series of air bubbles, each bubble separated by a volume of reagent.

Abstract: A method and apparatus for controlling a stream of liquid and air segments wherein the liquid and air segments are selectively aspirated into a first fluid conduit in a plurality of cycles, each cycle beginning with the aspiration of a first air segment and ending with the aspiration of a final air segment. The liquid and air segments are then transferred from the first fluid conduit to a second fluid conduit. The volume of the final air segment of each cycle is then adjusted after the final air segment has moved into the second fluid conduit. Next, the liquid segments and the air segments of each cycle are transferred from the second fluid conduit to a third fluid conduit. The volume of the first air segment of each cycle is then adjusted after the first air segment has moved into the third fluid conduit.

Abstract: The present invention relates to a system and method for moving samples, such as fluid, within a microfluidic system using a plurality of gas actuators for applying pressure at different locations within the microfluidic. The system includes a substrate which forms a fluid network through which fluid flows, and a plurality of gas actuators integral with the substrate. One such gas actuator is coupled to the network at a first location for providing gas pressure to move a microfluidic sample within the network. Another gas actuator is coupled to the network at a second location for providing gas pressure to further move at least a portion of the microfluidic sample within the network. A valve is coupled to the microfluidic network so that, when the valve is closed, it substantially isolates the second gas actuator from the first gas actuator.