New! View global litigation for patent families

US20040208751A1 - Microchip integrated multi-channel electroosmotic pumping system - Google Patents

Microchip integrated multi-channel electroosmotic pumping system Download PDF

Info

Publication number
US20040208751A1
US20040208751A1 US10478612 US47861203A US2004208751A1 US 20040208751 A1 US20040208751 A1 US 20040208751A1 US 10478612 US10478612 US 10478612 US 47861203 A US47861203 A US 47861203A US 2004208751 A1 US2004208751 A1 US 2004208751A1
Authority
US
Grant status
Application
Patent type
Prior art keywords
flow
microchannels
pumping
pump
electroosmotic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10478612
Inventor
Juliana Lazar
Barry Karger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Northeastern University (China)
Original Assignee
Northeastern University (China)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416Systems
    • G01N27/447Systems using electrophoresis
    • G01N27/44756Apparatus specially adapted therefor
    • G01N27/44791Microapparatus
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00Chemical, physical, or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0093Microreactors, e.g. miniaturised or microfabricated reactors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/50273Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the means or forces applied to move the fluids
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/502738Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by integrated valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B17/00Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B19/00Machines or pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B1/00 - F04B17/00
    • F04B19/006Micropumps
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K99/0001Microvalves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K99/0001Microvalves
    • F16K99/0003Constructional types of microvalves; Details of the cutting-off member
    • F16K99/0017Capillary or surface tension valves, e.g. using electro-wetting or electro-capillarity effects
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K99/0001Microvalves
    • F16K99/0003Constructional types of microvalves; Details of the cutting-off member
    • F16K99/0025Valves using microporous membranes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K99/0001Microvalves
    • F16K99/0034Operating means specially adapted for microvalves
    • F16K99/0042Electric operating means therefor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K99/0001Microvalves
    • F16K99/0034Operating means specially adapted for microvalves
    • F16K99/0042Electric operating means therefor
    • F16K99/0049Electric operating means therefor using an electroactive polymer [EAP]
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416Systems
    • G01N27/447Systems using electrophoresis
    • G01N27/44704Details; Accessories
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00781Aspects relating to microreactors
    • B01J2219/00783Laminate assemblies, i.e. the reactor comprising a stack of plates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00781Aspects relating to microreactors
    • B01J2219/00851Additional features
    • B01J2219/00853Employing electrode arrangements
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00781Aspects relating to microreactors
    • B01J2219/00851Additional features
    • B01J2219/00858Aspects relating to the size of the reactor
    • B01J2219/0086Dimensions of the flow channels
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00781Aspects relating to microreactors
    • B01J2219/00891Feeding or evacuation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00Additional constructional details
    • B01L2300/08Geometry, shape and general structure
    • B01L2300/0809Geometry, shape and general structure rectangular shaped
    • B01L2300/0816Cards, e.g. flat sample carriers usually with flow in two horizontal directions
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00Additional constructional details
    • B01L2300/08Geometry, shape and general structure
    • B01L2300/0861Configuration of multiple channels and/or chambers in a single devices
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00Additional constructional details
    • B01L2300/08Geometry, shape and general structure
    • B01L2300/0861Configuration of multiple channels and/or chambers in a single devices
    • B01L2300/0864Configuration of multiple channels and/or chambers in a single devices comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00Additional constructional details
    • B01L2300/08Geometry, shape and general structure
    • B01L2300/0861Configuration of multiple channels and/or chambers in a single devices
    • B01L2300/0867Multiple inlets and one sample wells, e.g. mixing, dilution
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00Moving or stopping fluids
    • B01L2400/04Moving fluids with specific forces or mechanical means
    • B01L2400/0403Moving fluids with specific forces or mechanical means specific forces
    • B01L2400/0415Moving fluids with specific forces or mechanical means specific forces electrical forces, e.g. electrokinetic
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01LCHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00Moving or stopping fluids
    • B01L2400/04Moving fluids with specific forces or mechanical means
    • B01L2400/0403Moving fluids with specific forces or mechanical means specific forces
    • B01L2400/0415Moving fluids with specific forces or mechanical means specific forces electrical forces, e.g. electrokinetic
    • B01L2400/0418Moving fluids with specific forces or mechanical means specific forces electrical forces, e.g. electrokinetic electro-osmotic flow [EOF]
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K2099/0073Fabrication methods specifically adapted for microvalves
    • F16K2099/0074Fabrication methods specifically adapted for microvalves using photolithography, e.g. etching
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16KVALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K99/00Subject matter not provided for in other groups of this subclass
    • F16K2099/0082Microvalves adapted for a particular use
    • F16K2099/0094Micropumps
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/10Devices for withdrawing samples in the liquid or fluent state
    • G01N1/14Suction devices, e.g. pumps; Ejector devices

Abstract

A microchip integrated microfabricated, microfluidic, multichannel, preferably electroosmotic pump and pumping system is disclosed. The electroosmotic pump of the invention comprises a plurality of microchannels, which begin and end in common compartments, complexed into an array. The microchannels within the pump have substantially identical, optimal dimensions of cross-section and length such that sufficient pressure for optimal flow of fluid (e.g., liquid or gas) and pressure is generated by the pump and flow rates are stable and reproducible. To effectuate efficient flow of fluid without the hindrance of backpressure, an electroosmotic pump of the invention is coupled to a single channel of a larger cross-section. A similar structure is also used in an electroosmotic valve of the invention, where samples are introduced into an analytical device. The microfluidic electroosmotic pumping system of the invention generates sufficient flow and pressures by optimizing the dimensional parameters of cross-section and length to the microchannels.

Description

    CROSS REFERENCE TO RELATED APPLICATIONS
  • [0001]
    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 60/292,780, filed May 22, 2001, entitled MICROCHIP INTEGRATED OPEN-CHANNEL ELECTROOSMOTIC PUMPING SYSTEM, the whole of which is hereby incorporated by reference herein.
  • STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
  • [0002] Part of the work leading to this invention was carried out with United States Government support provided under a grant from the National Institutes of Health, Grant No. GM15847. Therefore, the U.S. Government has certain rights in this invention.
  • BACKGROUND OF THE INVENTION
  • [0003]
    Microfluidics and instrument miniaturization1 have experienced significant growth in activity in recent years in response to the significant increase in use of microchips as bioanalytical tools. A major aspect of microfluidics refers to the manipulation of fluid flows in the microchip channels. For analytical processes, such as fluid valving,2,3 mixing,4 or electrically driven separations,2-5 flow streams are typically generated using electrical forces (electroosmotic flow, or EOF). However, EOF is dependent on the surface charge of the channel walls and consequently is sensitive to the physicochemical properties of the sample (pH, ionic strength, organic content). For example, the EOF can be easily reduced or even suppressed if the channel surface is altered by contact with specific sample types. Alternatively, for some techniques such as micro-liquid chromatography (μLC) or flow injection analysis (FIA), or for some samples, such as those containing cells that require zero electric field conditions for their manipulation, fluid flows on microchips may, or must, be generated by differential pressure.6-8 Typically, this is accomplished by connecting external devices to the microchip, e.g., vacuum, gas pressure generators or syringe pumps. However, the connection of external devices to microchips, while effective, increases the complexity of the system, and integration and multiplexing capabilities may be compromised.
  • [0004]
    A number of micropumps have been described in the art. Mechanical pumps that use a membrane actuated by various forces (e.g., piezoelectric, electromagnetic, pneumatic)9-15 are capable of pumping fluids of various physicochemical properties; however, the flow is pulsed, and the fabrication of the micropump is relatively complex. Non-mechanical pumps, with no moving parts, that operate on the basis of a large variety of principles (e.g., electrokinetic, centrifugal, electrohydrodynamic, etc.)16-29 have been implemented. The flow produced by these pumps is generally pulse free and varies from a few nL/min to hundreds of μL/min. However, the generated pressures are low, up to only a few psi. Fabrication procedures are often complex, as well.
  • [0005]
    The use of electroosmosis for pressurized pumping was advanced almost forty years ago30,31 and demonstrated later in open32 and packed16,17 capillary columns, and for open-channel microchip platforms.18-22 While packed electroosmotic pumps were shown to be capable of generating both flow and pressure, having packed particles or porous materials within the pump structure may, inter alia, impose limitations on the pumping channel size, may necessitate additional steps in pump fabrication and may affect reproducibility from one pump to another. The open-channel configurations were capable of producing flow but not sufficient pressure for the intended applications. Accordingly, it would be useful to have a microchip-integrated pumping device that simultaneously generates both sufficient flow and pressure for most analytical applications on a microchip and that is easy to fabricate, implement and use. Furthermore, an optimum pump design would ensure that a generated EOF is delivered to the analysis system and is not leaked out of the pump itself.
  • BRIEF SUMMARY OF THE INVENTION
  • [0006]
    The invention is directed to a microchip integrated microfabricated, microfluidic, multichannel, preferably electroosmotic pump and pumping system. The electroosmotic pump of the invention comprises a plurality of microchannels, which begin and end in common compartments, completed into an array. The microchannels within the pump have substantially identical, optimal dimensions of cross-section and length such that sufficient pressure for optimal flow of fluid (e.g., liquid or gas) and pressure is generated by the pump and flow rates are. stable and reproducible. In one aspect, the microchannels of the electroosmotic pump of the invention are open channels, i.e., not containing packed or porous materials. To effectuate efficient flow of fluid without the hindrance of backpressure, an electroosmotic pump of the invention is coupled to a single channel of a larger cross-section. A similar structure is also used in an electroosmotic valve of the invention, where samples are introduced into an analytical device. The microfluidic electroosmotic pumping system of the invention generates sufficient flow and pressures by optimizing the dimensional parameters of cross-section and length of the microchannels.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0007]
    Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof and from the claims, taken in conjunction with the accompanying drawings, in which:
  • [0008]
    [0008]FIG. 1 shows a schematic diagram of the microfabricated electroosmotic pumping system in accordance with the invention;
  • [0009]
    [0009]FIG. 2 shows a schematic diagram of a different embodiment of the microfabricated electroosmotic pumping system in accordance with the invention;
  • [0010]
    [0010]FIG. 3A shows representative flow, diameter and length in a schematic representation of a micropump with one pumping channel;
  • [0011]
    [0011]FIG. 3B shows a graph of the flow distribution, or the F/Feof coefficients calculated for a micropump with one microchannel at various d1/d2 ratios;
  • [0012]
    [0012]FIG. 4A shows a schematic representation of a micropump with n pumping channels;
  • [0013]
    [0013]FIG. 4B shows a graph of the flow distribution, or the F/Feof coefficients calculated for a micropump with n microchannels at d1/d2=0.1;
  • [0014]
    [0014]FIG. 5A shows a graph of a total forward flow generated in a pumping system with d1/d2=0.1 and L1/L2=0.1 with varying number of pumping channels;
  • [0015]
    [0015]FIG. 5B shows a graph of a total forward flow generated in a pumping system with d1/d2=0.1 and L1/L2=0.001 with varying number of pumping channels;
  • [0016]
    [0016]FIG. 6A shows a graph of achievable pressure as a function of the micropump channel diameter, for a restriction with d2=30 μm diameter (L1=0.03 m, L2=30 m, U=3000 V);
  • [0017]
    [0017]FIG. 6B shows a graph of achievable pressure as a function of the micropump channel diameter, for a restriction with d2=50 μm diameter (L1=0.03 m, L2=30 m, U=3000 V);
  • [0018]
    [0018]FIG. 7A shows a schematic diagram of an injection of a well delimited sample plug moving through the electroosmotic valve of the invention;
  • [0019]
    [0019]FIG. 7B shows a schematic diagram of a sample plug being transported down the channel in the electroosmotic valve of the invention;
  • [0020]
    [0020]FIG. 8A shows a schematic diagram of an electroosmotic pumping system functioning as an electroosmotic valve;
  • [0021]
    [0021]FIG. 8B shows a schematic diagram of an electroosmotic pumping system functioning as an electroosmotic valve;
  • [0022]
    [0022]FIG. 9 shows an exemplary multiplexed pumping system in accordance with the invention; and
  • [0023]
    [0023]FIG. 10A and FIG. 10B show a cross-sectional view and a plan view, respectively, of a micropump according to the invention having filtering and gating elements.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0024]
    The microfabricated microfluidic pumping system of the invention comprises one or more miniaturized pumping units, which are capable of stable fluid delivery at flow rates and backpressures compatible with common analytical applications carried out on a microchip and sufficiently small to enable multiplexing of individual pumps. A multiple channel micropump based on electroosmotic pumping principles in accordance with the invention comprises a plurality of parallel, small cross-section microchannels (e.g., narrow or shallow) that deliver fluid to a microchannel of larger cross-section. This design allows the simultaneous generation of both flow and pressure and can be implemented in both packed channel and open-channel configuration. In the context of this invention, an open-channel means that no packed particles or porous materials are added to or contained in the microchannels. The pumping system of the invention offers numerous advantages. First, it can easily be integrated on microfluidic platforms and utilized for fluid propulsion on a microchip. Secondly, its fabrication using standard photolithographic and wet chemical etching technologies (or other microelectromechanical systems (MEMS) technologies) ensures high manufacturing and operating reproducibility. Thirdly, the simplicity of the design ensures robustness, reliability and trouble free operation.
  • [0025]
    To illustrate the utility of an electroosmotic pumping system according to the invention, the micropump is designed to fit into an integrated microfluidic analysis scheme for delivery of, e.g., peptide samples for, e.g., electrospray ionization-mass spectrometry (ESI-MS) analysis. In addition, the ability to reproducibly control very low flow rates, at low and high pressure drops, where conventional systems do not perform well, enables the utilization of the micropump for many other micro-total analysis systems (μ-TAS) applications. The principle of μ-TAS is based on integrating all necessary parts and methods for analysis in miniaturized devices. The benefits of miniaturizing an analysis system include, but are not limited to, generation of multiple units at low cost; reduction in sample and reagent consumption and waste production; high throughput assays; small compact design; simple and reliable operation; and integration of several units or with existing systems.
  • [0026]
    Generally, the micropump of the invention can be used to deliver fluid flows in electric field free regions and perform sample transfer, gradient generation, or fraction collection/deposition. A large variety of applications can be envisioned for a micropump according to the invention, including, inter alia, eluent flow and/or pressure generation for condensed phase separation techniques (e.g., micro liquid chromatography in open, packed, monolithic or microfabricated channels, pressure assisted capillary electrochromatography or capillary electrophoresis, isoelectric focusing, affinity chromatography, immunoassays); single, parallel or sequential sample delivery for electrospray ionization-mass spectrometry (ESI-MS), matrix assisted laser desorption ionization (MALDI)-MS, optical detectors, or other detection systems; single, parallel or sequential sample delivery systems to microreactors, mixers, preconcentrators, filters, or other functional elements integrated on the microchip; single, parallel or sequential eluent or sample delivery systems to off-chip applications; solvent gradient generation for on or off-chip applications; solvent and reagent delivery for flow injection analysis; sample or sample fraction generation/dispensing/collection from microfluidic systems; sample or sample fraction deposition on MALDI-MS targets; sample transfer/delivery to, or from, combinatorial libraries; sample delivery for medical applications (external or animal implanted devices); generation of microreactors or sample alteration devices by chemically or physically modifying the surface of the micropuming channel walls, while simultaneously maintaining pumping capabilities; generation of multiplexed devices for high throughput screening by integration of a series of pumps on one single microchip platform; and generation of pressure or vacuum in a liquid or gas phase within a microfluidic device, or an attached additional device.
  • [0027]
    [0027]FIG. 1 illustrates a simplified schematic drawing of an exemplary microfabricated electroosmotic pumping system of the invention. A pumping unit 10 can be incorporated on one microchip device. However, multiple pumping units can also be incorporated, e.g., in parallel as shown in FIG. 2 and FIG. 9. The microchip device may be about a few square millimeters, e.g., 5-50 mm2. A multiplexed device (see, e.g., FIG. 9) that may contain, for example, eight, sixteen, or even 96 individual pumps may require a larger size chip. Pumping channel system 11 of pumping unit 10 comprises a plurality of first shallow microchannels 12 (e.g., 2-10,000 microchannels). All pumping channels 12 have first and second ends, which are in fluid communication with a common inlet 14 and a common outlet compartment or reservoir 16, respectively. Electrodes inserted in reservoirs 14 and 16 are connected to high voltage power supply 30 and are used to apply a voltage drop across the pump. The pumping channels are exposed only to buffer solutions and do not come in contact with any sample that may be added to the microchip. The pump size is quite variable and depends on the application (e.g., 1×10, 2×10, 5×50, 1×50 mm). The length of each microchannel may range from, e.g., about 5-50 mm. The channel depth, width, equivalent diameter or cross-section may range from about less than 1 μm to a few micrometers (e.g., 0.5-10 μm). The number of microchannels in one pump may range from two to more than a thousand (e.g., 2-10,000 channels). The spacing between the microchannels is in the low micrometer range (e.g., 1-50 μm). In one aspect, the pump unit of the invention comprises 4 microchannels, 10 microchannels, 25 microchannels, 100 microchannels or 1000 microchannels.
  • [0028]
    The pumping (or valve) system of the invention is activated by introducing into the channels a buffer or solvent, appropriate for preserving or increasing the surface charge on the pumping channel walls. The microchannels 12 can be filled by capillary action or by action of a pressure differential. Through electrodes placed in the reservoirs 14 and 16, a potential differential is applied across the microchannels 12. Depending on the surface properties of the channel (whether negatively or positively charged), the larger voltage must be applied to the appropriate reservoir, such that the electroosmotic flow will have the desired direction. For example, for a glass micropump having uncoated pumping channel walls, by applying a 2000 V on reservoir 14 and connecting reservoir 16 to ground, electroosmotic flow will be generated from reservoir 14 in the direction of reservoir 16. Electroosmotic flow is created due to the following mechanism. The functional groups on the pumping microchannel walls ionize in the presence of the solvent/fluid that is filling the microchannels and attract a layer of oppositely charged ions. When the potential differential is applied, this layer of oppositely charged ions start to move in the direction of the appropriate electrode (negative electrode for positively charged ions), dragging along bulk fluid flow. If this electroosmotic flow is restricted from evolving freely by the structure of the system or by the rest of the microfluidic channel network on the chip, pressure will be created inside the microfluidic structure, and the electroosmotic flow will be distributed through all the channels of the device through a pressure controlled mechanism. By reversing the polarity on the electrodes in reservoir 14 and 16, the direction of pumping will be reversed, and the pump will draw fluid out from the rest of the channels.
  • [0029]
    The pumping system delivers fluid via a common outlet compartment, connected to reservoir 16, to larger diameter second microchannel 13, which may be connected to a network of channels or to other devices. As shown in FIGS. 1, 7 and 8, second microchannel 13 is connected to network channel 20 for, e.g., sample infusion or separation. Channel 20 comprises electroosmotic valve 17 of the invention, which is used, e.g., for sample introduction. The electroosmotic valve is open to electroosmotic driven flows and essentially closed to pressure driven flows. At the other end of the network channel 20, an electrospray emitter 32, for example, or a detection or a sample collection device using any of the systems described above, can be integrated for analysis of a sample.
  • [0030]
    Sample injection in a microfabricated analysis systems is accomplished electrokinetically2,3 or by pressure gradients,44 and sample manipulations are performed with electrokinetic forces. If sample manipulations are to be performed using pressure driven flows, a fluid valving system, such as described here, is necessary to prevent leakage of the fluid flow into the sample or sample waste reservoirs. According to the invention, electroosmotic valving is accomplished using very narrow channels for the sample injection and waste lines, in a configuration similar to that of the electooosmotic pump. In a pressurized analysis system, narrow injection channels45 can act as efficient valving components. As shown in FIG. 1, 7 and 8, in a valve according to the invention, a sample can be infused electroosmotically from reservoir 22 to reservoir 24 through the sample and sample waste pluralities off channels, 26 and 28, respectively, and a double-T injector 18.46 The double-T injector can be an open or packed channel, e.g., as part of a preconcentration or μLC system. After completion of the injection, the pump can be started. For sample introduction and waste channels with similar dimensions to the pumping microchannels, additional pressure driven fluid loss through these channels could be negligible. Theoretically, if the number of injection and waste channels equals the number of pumping channels, the coefficient F/Feof would be unaffected by the injection/waste channels when d1/d2=0.01, and would drop to only 50% of its original value when d1/d2=0.1 (L1:L2=1:1000 in both cases).
  • [0031]
    In operation of the electroosmotic valve (as shown in FIG. 7A), all the appropriate channels and reservoirs of valve 17 and pump 10 are first filled with an appropriate eluent. Sample is injected into the valve inlet reservoir 22, and a voltage drop is established between reservoirs 22 and 24 to allow for a sample plug to be loaded into microchannel 20. The sample is electroosmotically carried from reservoir 22 in the direction of reservoir 24 by the application of a potential difference, e.g., 2000 V, between reservoir 22 and reservoir 24. A very small voltage drop (e.g., 100 V) between pump reservoir 14 and pump reservoir 16 may be needed on the pump unit 12 as well to help focus the injected plug in the microchannel 20.
  • [0032]
    As depicted in FIG. 7B, for injecting the sample plug down the microchannel 20 for analysis, a large voltage drop, e.g., 2000 V, between reservoir 14 and reservoir 16 is applied to the pumping unit 11. The electrodes in reservoirs 22 and 24 are maintained at the same value as the voltage on reservoir 16, or they are removed from these reservoirs, in order to suppress the electroosmotic flow in the direction of the sample and sample waste reservoirs. The voltage drop across the pump will generate electroosmotic flow in the pump and pressurized flow in the rest of the system. The large hydraulic resistance in the sample inlet and outlet channels will prevent back pressure leakage, or will allow for only a small flow leakage through these channels. Consequently, the sample plug will be transported only down the microchannel 20.
  • [0033]
    As shown in FIG. 8A, an electroosmotic pumping system composed of two parallel pumps can function, alternatively, as an electroosmotic valve, as well. One of the pumps, e.g., pump 10, is used for loading the sample, while the other pump, e.g., pump 100, is used for loading the eluent. Small, well delimited sample plugs, however, cannot be injected with this configuration.
  • [0034]
    In FIG. 8B, for injecting the plug for analysis, a large voltage drop is applied across pump 100, for example, 2000 V between reservoir 104 and reservoir 106. The voltage on reservoirs 14 and 16 is maintained at the same value as the voltage on reservoir 106, or the electrodes are removed from these reservoirs. The voltage drop across the pump 100 will generate electroosmotic flow in this pump, and pressurized flow in the rest of the system. For properly designed pumping channel diameters, the pressurized leakage flow through pump 12 will be minimal.
  • [0035]
    The potential differential for electroosmotic flow (EOF) generation is applied between the inlet and outlet reservoirs and may be provided by a power supply. Depending on the length of the pumping channels and the desired flow rate and pressure, the necessary voltage drop for the operation of the electroosmotic micropump may vary from a few tens to thousands of volts (e.g., 50-2000 V/cm).
  • [0036]
    In some configurations, outlet compartment or reservoir 16 can be common for systems with multiple pumps. Referring now to FIG. 10, a semi-permeable gate 34, that allows for an exchange of ions but not of the bulk eluent flow (liquid or gas), is created at the bottom of the outlet reservoir. The gate prevents EOF leakage in the direction of the exit electrode 35′ placed in the outlet reservoir. For example, a porous glass disc (e.g., 5 mm in diameter, 0.8-1 mm in width, and 40-50 Å pore size, prepared by Chang Associates (Worcester, Mass.)) can be used as the gate, but other materials may be used, e.g., graphite, polymeric organic or inorganic membrane materials. While most reservoirs on a microchip are made of glass, reservoir 16 is fabricated from a PEEK external nut. The porous glass disc is secured (e.g., between two gasket elements) at the bottom of reservoir 16 with a corresponding internal nut. This arrangement provides for robustness and exchangeability of the porous glass disc. Since the pumping microchannels act as a filter, clogging of some of the channels can occur. To reduce this effect, a short filter element 36 (e.g., 100 μm in length), of the same size and density as the collection of pumping channels, can be introduced, preferably at each end of the pump. Filter elements 36 are spaced from the ends of the pumping channels by intermediate compartments 38 and terminate at end compartments 14′ and 16′, respectively. In the embodiment shown, end compartments 14′, 16′ are connected to orifaces 40 in the substrate, which make connection with reservoirs 14 and 16 on the exterior surface of the substrate.
  • [0037]
    The pump can be fabricated in a variety of substrate materials such as, inter alia, glass, quartz, silicon, polysilicon, polymeric materials (organic or inorganic), ceramic, or other materials. The micropumps can be made using microfabrication techniques, for example, photolithography and wet chemical etching, or other microelectromechanical systems (MEMS) technologies (e.g., dry etching, laser ablation, injection molding, embossing, stamping).
  • [0038]
    Microfabricated devices that contain an electroosmotic micropump of the invention can be fabricated from one or two substrates made of any of the materials described above. The microfluidic channels can be made using one of the substrates described above by any of the microfabrication techniques. For example, micropump and sample handling channels defined on a photomask by 2 and 20 μm wide lines (other dimensions are possible) are transferred to the substrate using photolithography. After exposure, substrate etching is conducted to achieve channel depths of 0.5-10 μm for the micropump and 20-100 μm for sample handling. This substrate is placed into contact with the second (or top) substrate such that the surface of the second substrate is covering the channels of the first substrate. The two substrates are then bonded together to seal the enclosed channels. Alternatively, the micropump channels may be fabricated in the bottom substrate, while the rest of the microfluidic network of channels and chambers may be fabricated in the top substrate, made of the same or a different material as the bottom substrate. They come in contact with each other by proper alignment prior to bonding. Alternatively, the micropump may be fabricated in a substrate that is sandwiched between other two substrates.
  • [0039]
    The walls of the pumping channels may be the bare, unmodified surface or the chemically/physically altered surface of the substrate material that is used for the fabrication of the device. In the case of certain substrate materials, chemical treatment with, or physical adsorption of an appropriate surface coating agent on the pumping channel walls, may be necessary in order to provide for sufficient and adequate charged functional groups on these walls.
  • [0040]
    The holes or the apertures necessary to access the pumping channel and the other channels of the microfabricated device are fabricated prior to bonding in one or both of the substrates. These holes (typically of 1-2 mm in diameter) are used for the introduction of fluids and reagents into the chip, and for the placement of electrodes that ensure electrical contact with the network of microfluidic channels. These holes can also function as reservoirs for the solvent and reagents that are to be manipulated on the chip. To increase the volume of solvent or reagents that may be handled by the chip, additional reservoir structures may be attached to the access holes. Cooling or heating devices may be attached to the pump for specific applications.
  • [0041]
    Alternatively, in order to increase the resistance to back flow leakage, the straight microchannels can be replace by a tortuous arrangement, or even a more complicated microfabricated monolithic structure.
  • [0042]
    Alternatively, the electrodes may be embedded in the microfabricated device at appropriate positions. Embedded electrodes are fabricated using MEMS technologies prior to bonding of the two substrates.
  • [0043]
    Alternatively, the inlet and outlet reservoirs may be placed not directly on the pump inlet or outlet, but at the terminus of some larger channels, with small electrical resistance, that come in direct contact with the inlet and outlet of the pumping channels.
  • [0044]
    Alternatively, a structure (porous or multiple channel structure, etc.) with similar properties to the semi-permeable glass disc that is inserted in the outlet reservoir, can be created by MEMS technologies directly in the microchip body, at appropriate positions. This alternate gate structure can be used as fabricated, or it may be filled before utilization with an electrically conductive polymer that is replaceable. It will have the same function, to allow the exchange of ions but prevent transport of bulk flow.
  • [0045]
    Alternatively, in the case of configurations with two pumping units, the walls of the pumping microchannels of one or both pumps may be chemically or physically altered such that their surface is positively charged in the case of one of the pumps and negatively charged in the case of the second pump. Thus, by applying a potential differential between the two inlet reservoirs, 14 and 104, both pumps will generate electroosmotic flow in the same direction, but one will function under a positive voltage gradient, while the other will function under a negative voltage gradient. This configuration eliminates the need for the outlet reservoir 16 and the semi-permeable gate.
  • [0046]
    In another embodiment, the electrospraying or sample deposition capillary 32 may be replaced by a structure fabricated by MEMS technologies.
  • [0047]
    As shown in FIG. 2, to apply an eluent gradient with multiple pumps, e.g., two pumps 10 and 100, microchannels are filled with solvent or buffer. The solvent or buffer (SA) in reservoir 104 is replaced with a different solvent or buffer (SB). A porous glass disc 34 is placed and secured in reservoir 16 and 106. An identical voltage is applied to both reservoir 16 and 106. Voltages are then applied to reservoir 14 and 104 in a ratio that will provide the desired solvent mixture. The ratio of the two voltages is modulated (in steps or continuously) to generate a desired solvent gradient that is delivered to the system. The generated flow or pressure is monitored or measured.
  • [0048]
    In the present invention, a pump with a large number of narrow or shallow open microchannels is designed to produce EOF. Advantageously, the multiple microchannels ensure the generation of sufficient flow rate, while the small dimensions of the microchannels result in the necessary hydraulic resistance to pressurized back flow leakage. In contrast, a single, large diameter open-channel electroosmotic micropump could generate flow only if the backpressure is small, and the flow would be highly dependent on the backpressure.37 Properly designed, multiple channel pump configurations with small diameters according to the invention overcome this shortcoming, being capable of generating sufficient flow that is independent of backpressure. The pumping principles are further explained below.
  • [0049]
    Electroosmotic flow generation in single channels. To illustrate the principle of the open-channel electroosmotic micropump, an ideal system composed of cylindrical capillaries is considered and the conditions that must be met for proper pumping are examined. For this discussion, the contributions of local hydraulic resistances to the total pressure drop will be neglected. The standard equations that describe fluid flow and velocity in pressure driven (FΔp and vΔp) and electroosmotic driven (Feof and Veof) open capillary systems are as follows:38 F Δ p = π 128 η Δ p L d 4 ( 1 ) ν Δ p = 1 32 η Δ p L d 2 ( 2 ) F eof = πɛ o ɛ r ζ 4 η U L d 2 ( 3 ) ν eof = ɛ o ɛ r ζ η U L ( 4 )
    Figure US20040208751A1-20041021-M00001
  • [0050]
    where Δp =the pressure drop across a capillary of diameter d and length L, ρ=the viscosity of the fluid, εo=the electrical permitivity of the vacuum, εr=the relative permitivity of the medium (or dielectric constant), ζ=the zeta potential at the capillary wall, and U=the voltage applied across the capillary of length L. From equations (1) and (3), it can be seen that FΔp (Poisseuille flow) and Feof (electroosmotic flow) are dependent on d4 and on d2, respectively, due to the fact that vΔp is dependent on d2, while veof is independent of d. Therefore, if fluid flow generation and distribution in a microfluidic structure occurs by both Δp and EOF, a net fluid flow to be induced in preferential directions is expected.
  • [0051]
    Consider a system comprised of a single narrow channel (I) with dimensions d1 and L1 connected to a large channel (II) with dimensions d2 and L2 (FIG. 3A). If a potential drop is applied only to the narrow channel to generate flow through an electroosmotic mechanism (i.e., ˜d1 2), the flow in both channels can be redistributed through a pressure-controlled mechanism (i.e., ˜d1 4 and d2 4). Pressure generation is due to the fact that the field free capillary (II) acts as a restrictor for the Feof that is produced in capillary (I) under the influence of the electric field. The Feof will distribute into a forward flow through the large channel (F) and a back flow through the narrow channel (Fb). Pressurized fluid flow will be proportional to d1 4/d2 4 regardless of the method used to produce it. Practically, for a ratio of d1/d2 of only 1:10 (L1 being equal to L2), the flow will be distributed in a ratio F/Fb of 1:10,000, i.e., essentially all the flow will be directed through the large channel.
  • [0052]
    When both pressure and a potential gradient are applied to a capillary, the resulting flow is a sum of the Poiseuille and electroosmotic flows.30 By balancing the electroosmotic input flow (Feof) given by equation (3) with the pressurized output flows (F and Fb) given by equation (1), it can be shown that the pressurized forward flow (F) in the large channel is dependent on the EOF in the narrow channel (Feof), according to the following equation: F = F eof L 1 L 2 L 1 L 2 + ( d 1 d 2 ) 4 ( 5 )
    Figure US20040208751A1-20041021-M00002
  • [0053]
    The F/Feof ratio seems to be dependent on channel dimensions, but independent of pressure or the actual EOF in the system. F/Feof could be defined as an efficiency coefficient for a given pump, since it will determine what fraction of the originally produced EOF is actually pumped forward in the system. F/Feof values can be calculated from equation (5) and represented as a function of d1/d2 and L1/L2 (FIG. 3B). As seen, in this figure, small diameter and long pumping channels (i.e., small d1/d2 and large L1/L2 ratios), result in large F/Feof values and a more efficient electroosmotic pump. For example, for d1/d2=0.1, a relatively effective pump is created, since the F/Feof coefficient decreases from 1 to only 0.9 even when the large channel is very long and imposes a considerable backpressure (L1/L2=0.001).
  • [0054]
    Electroosmotic flow generation in multiple channels. For very small d, values, the actual EOF in a channel and consequently the overall flow in the system will be quite low. For a channel diameter of 1 μm, the EOF will be 0.17 nL/min [calculated from equation (3) for a capillary with L1=0.03 m and U=3000 V, and for parameters given in reference 45: εo=8.85×10−12 C2 N−1 m−2, εr=80, ζ=50×10−3 V, and n=0.001 N s m−2]. In order to compensate for this low EOF, multiple small diameter channels (n) can be connected to one large channel (FIG. 4A). However, in this case, by balancing again the flows, F will be defined by equation (6), and F/Feof will be dependent on n: F = F eof L 1 L 2 L 1 L 2 + n ( d 1 d 2 ) 4 ( 6 )
    Figure US20040208751A1-20041021-M00003
  • [0055]
    The larger n, the greater the total Feof, but F/Feof becomes smaller. F/Feof f values are represented as a function of n and L1/L2 for d1/d2=0.1 in FIG. 4B. For example, for d1/d2=0.1 and L1/L2=0.001, the F/Feof ratio drops from 0.9 to 0.09 when n is increased from 1 to 100.
  • [0056]
    The optimum number (n) and dimensions (d1 and L1) of the micropump channels that can generate the desired flow in the main channel can be calculated. If F/Feof is determined from equation (6) and multiply this value with the total EOF value calculated according to equation (3), diagrams that show the total pressure driven flow for given system characteristics (in this case d1/d2=0.1) can be constructed (FIG. 5). As expected, the total flow rate increases with the increase of d, and n. However, it is important to observe that when the backpressure increases significantly (i.e., L2 becomes much larger than L1), supplementing the pump with additional microchannels does not bring any additional benefit in increasing the flow rate (compare FIG. 5B and FIG. 5A). At high backpressures, the flow cannot be pumped, but rather will leak backwards in proportion to the number of channels n. The beneficial effect of increasing the number of microchannels requires properly chosen dimensions. At progressively smaller d1/d2 ratios, the back flow leakage becomes negligible. For example, as shown in Table 1, the F/Feof coefficients maintain a high and relatively constant value for a large range of pumping microchannels when d1/d2 drops to a value of 0.01. Based on the above considerations, and depending on the specific applications, micropumps with 100 to 1000 pumping channels of 1-3 μm in depth would perform as effective pumping systems on microfluidic platforms.
    TABLE 1
    Variation of F/Feof coefficient with d1/d2 and n (L1/L2 = 0.001)
    d1/d2 n = 1 n = 10 n = 100 n = 1000 n = 10000
    1 0.001 1E−04 1E−5 1E−6 1E−7
    0.1 0.909 0.5  0.091 0.009 0.001
    0.01 0.999 0.999 0.999 0.990 0.910
  • [0057]
    Electroosmotic pressure generation. The pressure that can be created in the system is calculated by balancing the input electroosmotic flow in the n narrow channels with the output pressure flow through all channels: Δ p = 32 n ɛ o ɛ r ζ U d 1 2 L 1 n d 1 4 L 1 + d 2 4 L 2 ( 7 )
    Figure US20040208751A1-20041021-M00004
  • [0058]
    A plot of this pressure as a function of pumping channel diameter, for given system characteristics, is shown in FIG. 6. It is worth noting that the pressure depends on the number and dimensions of the pumping microchannels, the voltage applied to the pump, the zeta potential, and the relative permitivity of the medium. The pressure is, however, not dependent on the fluid viscosity. In a system with enhanced restriction, i.e., d2=30 μm (FIG. 6A), the pressure will be higher than in a system with a lower restriction, i.e., d2=50 μm (FIG. 6B). The condition of maximum pressure: P d 1 = 0 ( 8 )
    Figure US20040208751A1-20041021-M00005
  • [0059]
    is accomplished when: nd 1 4 L 1 = d 2 4 L 2 ( 9 )
    Figure US20040208751A1-20041021-M00006
  • [0060]
    The absolute maximum pressure that can be generated with microchannels of a given dimension can be inferred from conditions of zero flow out from the system [.e., the second term in the denominator of equation (7) is set to zero], and is dependent only on the channel diameter, applied voltage and channel surface properties: Δ p max = 32 ɛ o ɛξU d 1 2 ( 10 )
    Figure US20040208751A1-20041021-M00007
  • [0061]
    For a pump that would be used for a LC separation, once the parameters of the separation column (d2, L2) and the optimum eluent flow rate are determined, the pressure necessary to generate this flow can be calculated, and the appropriate pump configuration (n, d1, and L1) can be chosen from diagrams such as shown in FIGS. 5 or 6. For a packed column, d2 and L2 are the dimensions of an equivalent open tubular LC column that produces the same pressure drop. Alternatively, the d2 4/L2 ratio in the denominator of equation (7) could be replaced by a term that takes into consideration the porosity and the permeability of the column. The microchip implementation of fully integrated micro-LC separations performed on polymeric monolithic stationary phases that are commonly performed under 100 psi39 thus becomes feasible with the integration of such pumping systems. Theoretically, (see equation 10), if pressure generation and not flow were the main purpose of these micropumps, and if microchip material and connecting elements would be capable of withstanding the high pressures, hunrdreds of bars could be produced with sub-micrometer sized channel EOF pumps.
  • [0062]
    Use
  • [0063]
    A stand-alone microfabricated device with an integrated multichannel EOF pump according to the invention has been constructed for producing controllable pressure driven flows within microfluidic channels. If desired, the pump can be constructed as a stand-alone module and can be employed to deliver fluid flow for on-chip or off-chip applications, as well. Micropumps with 4-100 pumping channels were constructed that produced flow rates in the range of 10-400 nL/min and developed pressures up to 80 psi. The flow rate and eluent gradients were adjusted by varying the potential drop over the pump. The experimental results followed closely the trends predicted by the theoretical calculations.
  • [0064]
    The new approach for microfluidic valving according to the invention, e.g., “electroosmotic valving,” in which sample plugs can be injected in pressurized systems, was tested for the investigation of peptide samples by MS analysis. The incorporation of an adsorbing medium for sample preconcentration in the double-T injector could prove useful in avoiding the electrophoretic bias effect, inherently associated with the use of electrokinetic forces for sample mobilization.
  • [0065]
    Two examples of system design to accomplish specific results follow:
  • [0066]
    Consider conducting a liquid chromatography separation in an open tubular capillary where the optimum separation parameters have been determined to be: d2=20 μm,. L2=0.5 m, and F=100 nL/min. The required pump design that can generate this flow rate in a liquid chromatography column can be determined from plots such as shown in FIG. 4A, which was constructed for d1/d2=0.1 and L1/L2=0.1. A pump with d1=2 μm, L1=0.05 m, and n=200, would generate about 110 nL/min.
  • [0067]
    Consider conducting a liquid chromatography separation in a column filled with monolith packing. The optimum separation parameters are: d2=150 μm, L2=0.05 m, F=700 nL/min, and the necessary pressure to generate this flow rate through the monolithic packing is about 3.4 bar. The equivalent column length that would generate a 3.4 bar pressure drop, at 700 nL/min and d2=150 μm, is L2=362 m. The appropriate pump design can be chosen, again from plots such as shown in FIG. 4A, or can be directly calculated. For instance, a pump with d1=2 μm, L1=0.05 m, and n=2000, would generate a total Feof=1320 nL/min. For the selected parameters, one can determine d1/d2=0.013, L1/L2=1.38, and F/Feof =0.70. Consequently, F can be calculated. A flow of F=910 nL/min will be produced, which is enough to drive the separation. Alternatively, a more efficient pump (d1=1-1.5 μm) that would guarantee a larger F/Feof coefficient could be chosen, as well.
  • [0068]
    In other embodiments, the electroosmotic pump according to the invention may be used with any other valving component, and the electroosmotic valve of the invention may be used with any other pump or pressure generating element (in particular, an electroosmotic/electrokinetic pump. The output of a pump and/or valve of the invention may be monitored via connection to a flow or pressure monitoring/controlling sensor and/or controller. A cluster of pumps may be attached to an individual network channel for, e.g., gradient generation or the introduction of a sequence of solvents into the system. A microfluidic device with a multiple channel structure constructed according to the invention allows for material transport driven by any mechanism (electric, magnetic, etc.) other than a pressure driven mechanism. Additionally, a microfluidic pump according to the invention can serve as an actuator for closing/opening of another valving component. The above microfluidic devices and pumps operate with aqueous and/or organic solutions, or other fluids (e.g., any liquid or gas).
  • REFERENCES
  • [0069]
    1. Manz, A.; Graber, N.; Widmer, H. M. Sens. Actuators, 1990, B1, 244-248.
  • [0070]
    2. Harrison D. J.; Manz, A.; Fan, Z.; Lüdi, H.; Widmer, H. M. Anal. Chem. 1992, 64, 1926-1932.
  • [0071]
    3. Jacobson, S. C.; Hergenröder, R.; Koutny, L. B.; Warmack, R. J.; Ramsey, J. M. Anal. Chem. 1994, 66, 1107-1113.
  • [0072]
    4. Jacobson, S. C.; McKnight, T. E.; Ramsey, J. M. Anal. Chem. 1999, 71, 4455-4459.
  • [0073]
    5. Jacobson, S. C.; Hergenroder, R.; Koutny, L. B.; Ramsey, J. M. Anal. Chem. 1994, 66, 2369-2373.
  • [0074]
    6. McEnery, M.; Tan, A.; Alderman, J.; Patterson, J.; O'Mathuna, S. C.; Glennon, J. D. Analyst 2000, 125, 25-27.
  • [0075]
    7. Huang, Y.; Rubinsky, B. Biomedical Microdevices 1999, 2(2), 145-150.
  • [0076]
    8. Liu, H.; Felten, C.; Xue, Q; Zhang, B.; Jedrzjewski, P.;
  • [0077]
    Karger, B. L.; Foret, F. Anal. Chem. 2000, 72, 3303-3310.
  • [0078]
    9. Francais, O.; Dufour, I. J. Micromech. Microeng. 2000, 10, 282-286.
  • [0079]
    10. Gong, Q.; Zhou, Z.; Yang, Y.; Wang, X. Sens. Actuators A 2000, 83, 200-207:
  • [0080]
    11. Accoto, D.; Carozza, M. C.; Dario, P. J. Micromech. Microeng. 2000, 10, 277-281.
  • [0081]
    12. Laurell, T.; Waliman, L.; Nilsson, J. J. Micromech. Microeng. 1999, 9, 369-376.
  • [0082]
    13. Kar, S.; McWhorter, S.; Ford, S. M.; Soper, S. A. Analyst 1998, 123, 1435-1441.
  • [0083]
    14. Jeong, O. C.; Yang, S. S. Sens. Actuators A 2000, 83, 249-255.
  • [0084]
    15. Handique, K.; Burke, D. T.; Mastrangelo, C. H.; Burns, M. A. Anal. Chem. 2001, 73 (8), 1831-1838.
  • [0085]
    16. Paul, P. H.; Arnold, D. W.; Rakestraw, D. J. Proceedings of the Micro Total Analysis Systems '98 Workshop, p. 49-52. Banff, Canada, 13-16 Oct., 1998.
  • [0086]
    17. Paul, P. H.; Arnold, D. W.; Neyer, D. W.; Smith, K. B. Proceedings of the Micro Total Analysis Systems 2000 Symposium, p. 583-590. Enschede, Netherlands, 14-18 May, 2000.
  • [0087]
    18. Lazar, I. M.; Ramsey, R. S.; Jacobson, S. C.; Foote, R. S.; Ramsey, J. M. J. Chromatogr. A 2000, 892, 195-201.
  • [0088]
    19. McKnight, T. E.; Culbertson, C. T.; Jacobson, S. C.; Ramsey, J. M. Anal. Chem. 2001, 73(16), 4045-4049.
  • [0089]
    20. Zeng, S.; Chen, C.-H.; Mikkelsen, J. C., Jr.; Santiago, J. C. Sensors and Actuators B, 2001, 79, 107-114.
  • [0090]
    21. Morf, W. E.; Guenat, O. T.; de Rooij, N. F. Sensors and Actuators B, 2001, 72, 266-272.
  • [0091]
    22. Guenat, O. T.; Ghiglione, D.; Morf, W. E.; de Rooij, N. F. Sensors and Actuators B, 2001, 72, 273-282.
  • [0092]
    23. McBride, S. E.; Moroney, R. M.; Chiang, W. Proceedings of the Micro Total Analysis Systems '98 Workshop, p. 45-48. Banff, Canada, 13-16 Oct., 1998.
  • [0093]
    24. Jang, J.; Lee, S. S. Sensors and Actuators A 2000, 80, 84-89.
  • [0094]
    25. Lemoff, A. V.; Lee, A. P. Sensors and Actuators B 2000, 63, 178-185.
  • [0095]
    26. Sammarco, T. S.; Burns, M. A. J. Micromech. Microeng. 2000, 10, 42-55.
  • [0096]
    27. Prins, M. W. J.; Welters, W. J. J.; Weekamp, J. W. Science, 2001, 291(12), 277-280.
  • [0097]
    28. Rife, J. C.; Bell, M. I.; Horwitz, J. S.; Kabler, M. N.; Auyeung, R. C. Y.; Kim, W. J. Sens. Actuators A 2000, 86, 135-140.
  • [0098]
    29. Duffy, D. C.; Gillis, H. L.; Lin, J.; Sheppard, N. F., Jr.;
  • [0099]
    Kellogg, G. J. Anal. Chem. 1999, 71(20), 4669-4678.
  • [0100]
    30. Rice, C. L.; Whitehead, R. J. Phys. Chem. 1965, 69(11), 4017-4024.
  • [0101]
    31. Pretorius, V.; Hopkins, B. J.; Schieke, J. D. J. Chromatogr. 1974, 99, 23-30.
  • [0102]
    32. Dasgupta, P. K.; Liu, S. Anal. Chem. 1994, 66, 1792-1798.
  • [0103]
    33. Wallingford, R. A.; Ewing, A. G. Anal. Chem. 1987, 59, 1762-1766.
  • [0104]
    34. O'Shea, T. J.; Greenhagen, R. D.; Lunte, S. M.; Lunte, C. E.; Smyth, M. R.; Radzik, D. M.; Watanabe, N. J. Chromatogr. 1992, 593, 305-312.
  • [0105]
    35. Hu, S.; Wang, Z.-L.; Li, P.-B.; Cheng, J.-K. Anal. Chem. 1997, 69, 264-267.
  • [0106]
    36. Lazar, I. M.; Ramsey, R. S., Ramsey, J. M. Anal. Chem. 2001, 73, 1733-1739.
  • [0107]
    37. Parce, J. W., U.S. Pat. No. 6012902, 2000.
  • [0108]
    38. Knox, J. H.; Grant, I. H. Chromatographia, 1987, 24, 135-143.
  • [0109]
    39. Moore, R. E.; Licklider L.; Schumann, D.; Lee, T. D. Anal. Chem. 1998, 70, 4879-4884.
  • [0110]
    40. Stevens, T. S.; Cortes, H. J. Anal. Chem. 1983, 55, 1365-1370.
  • [0111]
    41. Kutter, J. P.; Jacobson, S. C.; Ramsey, J. M. Anal. Chem. 1997, 69, 5165-5171.
  • [0112]
    42. Jakeway, S. C.; de Mello, A. J.; Russell, E. L. Fresenius J. Anal. Chem. 2000, 366, 525-539.
  • [0113]
    43. He, B.; Burke, B. J.; Zhang, X.; Zhang, R.; Regnier, F. E. Anal. Chem. 2001, 73, 1942-1947.
  • [0114]
    44. Zhang, B.; Foret, F.; Karger, B. L. Anal. Chem. 2001, 73, 2675-2681.
  • [0115]
    45. Zhang, C.-X.; Manz, A. Anal. Chem. 2001, 73, 2656-2662.
  • [0116]
    46. Effenhauser, C. S.; Manz, A.; Widmer, H. M. Anal. Chem. 1993, 65, 2637-2642.
  • [0117]
    While the present invention has been described in conjunction with a preferred embodiment, one of ordinary skill, after reading the foregoing specification, will be able to effect various changes, substitutions of equivalents, and other alterations to the compositions and methods set forth herein. It is therefore intended that the protection granted by Letters Patent hereon be limited only by the definitions contained in the appended claims and equivalents thereof.

Claims (20)

    What is claimed is:
  1. 1. A microfluidic pump or valve device comprising:
    a substrate, said substrate comprising:
    a plurality of first microchannels, each of said first microchannels having a first and a second end, wherein said first ends of said first microchannels originate at a common inlet compartment and wherein said second ends of said first microchannels terminate at a common outlet compartment.
  2. 2. The microfluidic device of claim 1, wherein said first microchannels are open-channeled.
  3. 3. The microfluidic device of claim 1, wherein said plurality of first microchannels comprises at least 5 microchannels.
  4. 4. The microfluidic device of claim 1, wherein said plurality of first microchannels comprises at least 50 microchannels.
  5. 5. The microfluidic device of claim 1, wherein said plurality of first microchannels comprises at least 100 microchannels.
  6. 6. The microfluidic device of claim 1, wherein said plurality of first microchannels comprises at least 1,000 microchannels.
  7. 7. The microfluidic device of claim 1, wherein said plurality of first microchannels comprises at least 10,000 microchannels.
  8. 8. The microfluidic device of claim 1, wherein said plurality of first microchannels are in a substantially parallel configuration.
  9. 9. The microfluidic device of claim 1, wherein said plurality of first microchannels are in a tortuous configuration.
  10. 10. The microfluidic device of claim 1, said device further comprising an electrode embedded in said common outlet compartment.
  11. 11. The microfluidic device of claim 1, said device further comprising an electrode embedded in said common inlet compartment.
  12. 12. The microfluidic device of claim 1, said device further comprising an oriface connecting said inlet compartment to a surface of said substrate.
  13. 13. The microfluidic device of claim 1, said device further comprising an oriface connecting said outlet compartment to a surface of said substrate.
  14. 14. The microfluidic device of claim 1, said device further comprising a second microchannel coupled to said outlet compartment, wherein said second microchannel is larger in cross-section than an individual said first microchannel.
  15. 15. A microfluidic system configured in a substrate, said system comprising:
    (a) an electroosmotic pump comprising:
    (i) a plurality of first microchannels fabricated in said substrate, each of said first microchannels having a first and a second end, wherein said first ends of said first microchannels originate at a common inlet compartment and wherein said second ends of said first microchannels terminate at a common outlet compartment; and
    (ii) a voltage source coupled to said inlet and outlet compartments for said first microchannels;
    (b) a second microchannel, said second microchannel having a larger cross-section than each of said plurality of first microchannels, said second microchannel having first and second ends, wherein said common outlet compartment of said first microchannels is in fluid communication with said first end of said second microchannel; and
    (c) an electroosmotic valve comprising:
    (i) two sets of a plurality of third microchannels fabricated on said substrate, said third microchannels each having a smaller cross-section than said said second channel, each of said third microchannels having a first and a second end, wherein said first ends of said first set of a plurality of third microchannels originate at a common inlet compartment, wherein said second ends of said first set of a plurality of third microchannels is in fluid communication with said second microchannel, wherein said second ends of said second set of a plurality of third microchannels is also in fluid communication with said second microchannel and wherein said first ends of said second set of a plurality of third microchannels terminate at a common outlet compartment; and
    (vi) a voltage source coupled to said inlet and outlet compartments.
  16. 16. The microfluidic system system of claim 15, wherein the ratio of the diameter of a said first microchannel to the diameter of said second microchannel is 1:1.25-1:1000.
  17. 17. The microfluidic system system of claim 15, wherein said substrate material is selected from the group consisting of glass, quartz, silicon, polysilicon, polymeric materials (organic or inorganic) and ceramic.
  18. 18. The microfluidic system system of claim 15, wherein said outlet compartment associated with said plurality of firsts microchannels comprises a semi-permeable gate.
  19. 19. The microfluidic system system of claim 15, wherein said semi-permeable gate is selected from the group consisting of a porous glass, graphite, and polymeric organic or inorganic material.
  20. 20. A method of transporting a material for analysis through a microchannel in a microchip, said method comprising the steps of:
    providing in said microchip a plurality of first microchannels and a second microchannel, wherein said second microchannel has a first and a second end, wherein the cross-section of each of said first microchannels is smaller than the cross-section of said second microchannel, wherein said first end of said second microchannel is in fluid communication with said plurality of first microchannels at one end of each and wherein said second end of said second microchannel is in communication with a detection system for analysis of a sample;
    introducing a sample into said second microchannel; and
    applying a potential difference across a length of said plurality of microchannels to electroosmotically move said sample in said second microchannel.
US10478612 2001-05-22 2002-05-22 Microchip integrated multi-channel electroosmotic pumping system Abandoned US20040208751A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US29278001 true 2001-05-22 2001-05-22
US10478612 US20040208751A1 (en) 2001-05-22 2002-05-22 Microchip integrated multi-channel electroosmotic pumping system
PCT/US2002/016207 WO2002094440A3 (en) 2001-05-22 2002-05-22 Microchip integrated multichannel electroosmotic pumping system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10478612 US20040208751A1 (en) 2001-05-22 2002-05-22 Microchip integrated multi-channel electroosmotic pumping system

Publications (1)

Publication Number Publication Date
US20040208751A1 true true US20040208751A1 (en) 2004-10-21

Family

ID=23126156

Family Applications (1)

Application Number Title Priority Date Filing Date
US10478612 Abandoned US20040208751A1 (en) 2001-05-22 2002-05-22 Microchip integrated multi-channel electroosmotic pumping system

Country Status (2)

Country Link
US (1) US20040208751A1 (en)
WO (1) WO2002094440A3 (en)

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004002878A2 (en) * 2002-06-26 2004-01-08 California Institute Of Technology Microfluidic devices and methods with electrochemically actuated sample processing
US20040241004A1 (en) * 2003-05-30 2004-12-02 Goodson Kenneth E. Electroosmotic micropump with planar features
US20050220681A1 (en) * 2004-03-19 2005-10-06 State of Oregon acting by and through the State Board of Higher Education on behalf of Microchemical nanofactories
US20060193748A1 (en) * 2002-06-26 2006-08-31 Yu-Chong Tai Integrated LC-ESI on a chip
US20060254913A1 (en) * 2005-05-10 2006-11-16 Myers Alan M Orientation independent electroosmotic pump
WO2007034267A1 (en) * 2005-07-07 2007-03-29 Obshchestvo S Ogranichennoj Otvetstvennostyu 'institut Rentgenovskoj Optiki' Electrokinetic micropump
US20070184576A1 (en) * 2005-11-29 2007-08-09 Oregon State University Solution deposition of inorganic materials and electronic devices made comprising the inorganic materials
WO2008033021A1 (en) * 2006-09-15 2008-03-20 Stichting Voor De Technische Wetenschappen Moving field capillary electrophoresis with sample plug dispersion compensation
US20080073506A1 (en) * 2006-08-24 2008-03-27 Lazar Iuliana M Microfluidic devices and methods facilitating high-throughput, on-chip detection and separation techniques
US20080102119A1 (en) * 2006-11-01 2008-05-01 Medtronic, Inc. Osmotic pump apparatus and associated methods
US20080108122A1 (en) * 2006-09-01 2008-05-08 State of Oregon acting by and through the State Board of Higher Education on behalf of Oregon Microchemical nanofactories
US20080152509A1 (en) * 2006-02-24 2008-06-26 Hsueh-Chia Chang Integrated micro-pump and electro-spray
US20100120260A1 (en) * 2008-11-12 2010-05-13 Jiou-Kang Lee Multi-Step Process for Forming High-Aspect-Ratio Holes for MEMS Devices
US20100168457A1 (en) * 2006-11-07 2010-07-01 Waters Technologies Corporation Monolithic electrokinetic pump fabrication
US20110005605A1 (en) * 2008-04-09 2011-01-13 Arkray, Inc. Liquid delivery control method and liquid delivery control system
US20110023728A1 (en) * 2009-07-29 2011-02-03 Searete Llc, A Limited Liability Corporation Of The State Of Delaware Pasteurization system and method
US8137554B2 (en) 2004-10-06 2012-03-20 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Microfluidic devices, particularly filtration devices comprising polymeric membranes, and method for their manufacture and use
US8236599B2 (en) 2009-04-09 2012-08-07 State of Oregon acting by and through the State Board of Higher Education Solution-based process for making inorganic materials
CN103041879A (en) * 2012-12-31 2013-04-17 苏州汶颢芯片科技有限公司 Micro-fluidic chip for micro/nano liter quota-sampling and preparation method thereof
CN103071554A (en) * 2012-12-31 2013-05-01 苏州汶颢芯片科技有限公司 Microfluidic chip for circularly driving solution and preparation method thereof
US8501009B2 (en) 2010-06-07 2013-08-06 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Fluid purification system
US8580161B2 (en) 2010-05-04 2013-11-12 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Fluidic devices comprising photocontrollable units
US8603834B2 (en) 2011-12-15 2013-12-10 General Electric Company Actuation of valves using electroosmotic pump
US8801922B2 (en) 2009-06-24 2014-08-12 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Dialysis system
US9328969B2 (en) 2011-10-07 2016-05-03 Outset Medical, Inc. Heat exchange fluid purification for dialysis system
US9402945B2 (en) 2014-04-29 2016-08-02 Outset Medical, Inc. Dialysis system and methods
WO2016053936A3 (en) * 2014-09-29 2016-09-22 The University Of Florida Research Foundation, Inc. Electro-fluid transducers
US9545469B2 (en) 2009-12-05 2017-01-17 Outset Medical, Inc. Dialysis system with ultrafiltration control
US9599407B2 (en) 2009-07-29 2017-03-21 Tokitae Llc System and structure for heating or sterilizing a liquid stream
US9930898B2 (en) * 2009-07-29 2018-04-03 Tokitae Llc Pasteurization system and method

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2382538C (en) 2001-09-20 2008-12-12 Univ Hull Device having a liquid flowpath
DE60312990T2 (en) * 2002-08-02 2007-12-13 GE Healthcare (SV) Corp., Sunnyvale An integrated microchip design
NL1023404C2 (en) * 2003-05-13 2004-11-16 Berkin Bv Device for controlling the mass flow rate of a fluid flow in a fluid channel.
FR2857099B1 (en) * 2003-07-04 2005-10-07 Jean Marie Billiotte Method and chemical or biological analysis device by a sensor chamber monolithic multi-tubular micro-jet and lateral measurement transducer integrale
US7722817B2 (en) 2003-08-28 2010-05-25 Epocal Inc. Lateral flow diagnostic devices with instrument controlled fluidics
US7084495B2 (en) * 2003-10-16 2006-08-01 Intel Corporation Electroosmotic pumps using porous frits for cooling integrated circuit stacks
US6992381B2 (en) 2003-10-31 2006-01-31 Intel Corporation Using external radiators with electroosmotic pumps for cooling integrated circuits
KR20060132434A (en) 2003-11-06 2006-12-21 라이프스캔, 인코포레이티드 Drug delivery pen with event notification means
EP2579977A4 (en) * 2010-06-09 2017-09-13 Empire Technology Dev Llc Adjustable pressure microreactor

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4908112A (en) * 1988-06-16 1990-03-13 E. I. Du Pont De Nemours & Co. Silicon semiconductor wafer for analyzing micronic biological samples
US5296375A (en) * 1992-05-01 1994-03-22 Trustees Of The University Of Pennsylvania Mesoscale sperm handling devices
US5632876A (en) * 1995-06-06 1997-05-27 David Sarnoff Research Center, Inc. Apparatus and methods for controlling fluid flow in microchannels
US6062261A (en) * 1998-12-16 2000-05-16 Lockheed Martin Energy Research Corporation MicrofluIdic circuit designs for performing electrokinetic manipulations that reduce the number of voltage sources and fluid reservoirs
US6319469B1 (en) * 1995-12-18 2001-11-20 Silicon Valley Bank Devices and methods for using centripetal acceleration to drive fluid movement in a microfluidics system
US6440645B1 (en) * 1997-07-18 2002-08-27 Cambridge Sensors Limited Production of microstructures for use in assays
US6766817B2 (en) * 2001-07-25 2004-07-27 Tubarc Technologies, Llc Fluid conduction utilizing a reversible unsaturated siphon with tubarc porosity action

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4908112A (en) * 1988-06-16 1990-03-13 E. I. Du Pont De Nemours & Co. Silicon semiconductor wafer for analyzing micronic biological samples
US5296375A (en) * 1992-05-01 1994-03-22 Trustees Of The University Of Pennsylvania Mesoscale sperm handling devices
US5632876A (en) * 1995-06-06 1997-05-27 David Sarnoff Research Center, Inc. Apparatus and methods for controlling fluid flow in microchannels
US6319469B1 (en) * 1995-12-18 2001-11-20 Silicon Valley Bank Devices and methods for using centripetal acceleration to drive fluid movement in a microfluidics system
US6440645B1 (en) * 1997-07-18 2002-08-27 Cambridge Sensors Limited Production of microstructures for use in assays
US6062261A (en) * 1998-12-16 2000-05-16 Lockheed Martin Energy Research Corporation MicrofluIdic circuit designs for performing electrokinetic manipulations that reduce the number of voltage sources and fluid reservoirs
US6766817B2 (en) * 2001-07-25 2004-07-27 Tubarc Technologies, Llc Fluid conduction utilizing a reversible unsaturated siphon with tubarc porosity action

Cited By (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004002878A3 (en) * 2002-06-26 2007-04-26 California Inst Of Techn Microfluidic devices and methods with electrochemically actuated sample processing
US20040124085A1 (en) * 2002-06-26 2004-07-01 California Institute Of Technology Microfluidic devices and methods with electrochemically actuated sample processing
US20060193748A1 (en) * 2002-06-26 2006-08-31 Yu-Chong Tai Integrated LC-ESI on a chip
US7976779B2 (en) * 2002-06-26 2011-07-12 California Institute Of Technology Integrated LC-ESI on a chip
WO2004002878A2 (en) * 2002-06-26 2004-01-08 California Institute Of Technology Microfluidic devices and methods with electrochemically actuated sample processing
US20040241004A1 (en) * 2003-05-30 2004-12-02 Goodson Kenneth E. Electroosmotic micropump with planar features
US7316543B2 (en) * 2003-05-30 2008-01-08 The Board Of Trustees Of The Leland Stanford Junior University Electroosmotic micropump with planar features
US7507380B2 (en) * 2004-03-19 2009-03-24 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Microchemical nanofactories
US20050220681A1 (en) * 2004-03-19 2005-10-06 State of Oregon acting by and through the State Board of Higher Education on behalf of Microchemical nanofactories
US8137554B2 (en) 2004-10-06 2012-03-20 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Microfluidic devices, particularly filtration devices comprising polymeric membranes, and method for their manufacture and use
US8273245B2 (en) 2004-10-06 2012-09-25 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Microfluidic devices, particularly filtration devices comprising polymeric membranes, and methods for their manufacture and use
US20060254913A1 (en) * 2005-05-10 2006-11-16 Myers Alan M Orientation independent electroosmotic pump
US7645368B2 (en) 2005-05-10 2010-01-12 Intel Corporation Orientation independent electroosmotic pump
WO2007034267A1 (en) * 2005-07-07 2007-03-29 Obshchestvo S Ogranichennoj Otvetstvennostyu 'institut Rentgenovskoj Optiki' Electrokinetic micropump
US20070184576A1 (en) * 2005-11-29 2007-08-09 Oregon State University Solution deposition of inorganic materials and electronic devices made comprising the inorganic materials
US8679587B2 (en) 2005-11-29 2014-03-25 State of Oregon acting by and through the State Board of Higher Education action on Behalf of Oregon State University Solution deposition of inorganic materials and electronic devices made comprising the inorganic materials
US20080152509A1 (en) * 2006-02-24 2008-06-26 Hsueh-Chia Chang Integrated micro-pump and electro-spray
US20080073506A1 (en) * 2006-08-24 2008-03-27 Lazar Iuliana M Microfluidic devices and methods facilitating high-throughput, on-chip detection and separation techniques
US7744762B2 (en) * 2006-08-24 2010-06-29 Virginia Tech Intellectual Properties, Inc. Microfluidic devices and methods facilitating high-throughput, on-chip detection and separation techniques
US20080108122A1 (en) * 2006-09-01 2008-05-08 State of Oregon acting by and through the State Board of Higher Education on behalf of Oregon Microchemical nanofactories
WO2008033021A1 (en) * 2006-09-15 2008-03-20 Stichting Voor De Technische Wetenschappen Moving field capillary electrophoresis with sample plug dispersion compensation
US20080102119A1 (en) * 2006-11-01 2008-05-01 Medtronic, Inc. Osmotic pump apparatus and associated methods
US20110184389A1 (en) * 2006-11-01 2011-07-28 Medtronic, Inc. Osmotic pump apparatus and associated methods
US8680311B2 (en) 2006-11-07 2014-03-25 Waters Technologies Corporation Monolithic electrokinetic pump fabrication
US20100168457A1 (en) * 2006-11-07 2010-07-01 Waters Technologies Corporation Monolithic electrokinetic pump fabrication
US20110005605A1 (en) * 2008-04-09 2011-01-13 Arkray, Inc. Liquid delivery control method and liquid delivery control system
US20100120260A1 (en) * 2008-11-12 2010-05-13 Jiou-Kang Lee Multi-Step Process for Forming High-Aspect-Ratio Holes for MEMS Devices
US7923379B2 (en) 2008-11-12 2011-04-12 Taiwan Semiconductor Manufacturing Company, Ltd. Multi-step process for forming high-aspect-ratio holes for MEMS devices
US8236599B2 (en) 2009-04-09 2012-08-07 State of Oregon acting by and through the State Board of Higher Education Solution-based process for making inorganic materials
US8801922B2 (en) 2009-06-24 2014-08-12 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Dialysis system
US9599407B2 (en) 2009-07-29 2017-03-21 Tokitae Llc System and structure for heating or sterilizing a liquid stream
US20110023728A1 (en) * 2009-07-29 2011-02-03 Searete Llc, A Limited Liability Corporation Of The State Of Delaware Pasteurization system and method
US9930898B2 (en) * 2009-07-29 2018-04-03 Tokitae Llc Pasteurization system and method
US9545469B2 (en) 2009-12-05 2017-01-17 Outset Medical, Inc. Dialysis system with ultrafiltration control
US8580161B2 (en) 2010-05-04 2013-11-12 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Fluidic devices comprising photocontrollable units
US8524086B2 (en) 2010-06-07 2013-09-03 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Fluid purification system
US8501009B2 (en) 2010-06-07 2013-08-06 State Of Oregon Acting By And Through The State Board Of Higher Education On Behalf Of Oregon State University Fluid purification system
US9895480B2 (en) 2010-06-07 2018-02-20 Oregon State University Dialysis system
US9138687B2 (en) 2010-06-07 2015-09-22 Oregon State University Fluid purification system
US9328969B2 (en) 2011-10-07 2016-05-03 Outset Medical, Inc. Heat exchange fluid purification for dialysis system
US9188113B2 (en) 2011-12-15 2015-11-17 General Electric Company Actuation of valves using electroosmotic pump
US8603834B2 (en) 2011-12-15 2013-12-10 General Electric Company Actuation of valves using electroosmotic pump
CN103041879A (en) * 2012-12-31 2013-04-17 苏州汶颢芯片科技有限公司 Micro-fluidic chip for micro/nano liter quota-sampling and preparation method thereof
CN103071554A (en) * 2012-12-31 2013-05-01 苏州汶颢芯片科技有限公司 Microfluidic chip for circularly driving solution and preparation method thereof
US9402945B2 (en) 2014-04-29 2016-08-02 Outset Medical, Inc. Dialysis system and methods
US9579440B2 (en) 2014-04-29 2017-02-28 Outset Medical, Inc. Dialysis system and methods
US9504777B2 (en) 2014-04-29 2016-11-29 Outset Medical, Inc. Dialysis system and methods
WO2016053936A3 (en) * 2014-09-29 2016-09-22 The University Of Florida Research Foundation, Inc. Electro-fluid transducers

Also Published As

Publication number Publication date Type
WO2002094440A2 (en) 2002-11-28 application
WO2002094440A3 (en) 2003-03-13 application

Similar Documents

Publication Publication Date Title
US6870185B2 (en) Integrated microchip design
Wheeler et al. Digital microfluidics with in-line sample purification for proteomics analyses with MALDI-MS
US6536477B1 (en) Fluidic couplers and modular microfluidic systems
US6602791B2 (en) Manufacture of integrated fluidic devices
Lichtenberg et al. Sample pretreatment on microfabricated devices
US7192559B2 (en) Methods and devices for high throughput fluid delivery
US6001229A (en) Apparatus and method for performing microfluidic manipulations for chemical analysis
Sia et al. Microfluidic devices fabricated in poly (dimethylsiloxane) for biological studies
Broyles et al. Sample filtration, concentration, and separation integrated on microfluidic devices
US5571410A (en) Fully integrated miniaturized planar liquid sample handling and analysis device
US5958203A (en) Electropipettor and compensation means for electrophoretic bias
Khandurina et al. Bioanalysis in microfluidic devices
US7863035B2 (en) Fluidics devices
Huikko et al. Introduction to micro-analytical systems: bioanalytical and pharmaceutical applications
US8075754B2 (en) Electrowetting pumping device and use for measuring electrical activity
Kim et al. Self-sealed vertical polymeric nanoporous-junctions for high-throughput nanofluidic applications
Haswell Development and operating characteristics of micro flow injection based on electroosmotic flow
US6981522B2 (en) Microfluidic devices with distributing inputs
US6866762B2 (en) Dielectric gate and methods for fluid injection and control
US20050205816A1 (en) Pneumatic valve interface for use in microfluidic structures
van den Berg et al. Micro total analysis systems: microfluidic aspects, integration concept and applications
US5872010A (en) Microscale fluid handling system
US6899137B2 (en) Microfabricated elastomeric valve and pump systems
US20020164816A1 (en) Microfluidic sample separation device
Ceriotti et al. An integrated fritless column for on-chip capillary electrochromatography with conventional stationary phases

Legal Events

Date Code Title Description
AS Assignment

Owner name: NORTHEASTERN UNIVERSITY, MASSACHUSETTS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LAZAR, IULIANA;KARGER, BARRY L.;REEL/FRAME:016297/0657;SIGNING DATES FROM 20040113 TO 20040115

AS Assignment

Owner name: NATIONAL INSTITUTES OF HEALTH (NIH), U.S. DEPT. OF

Free format text: CONFIRMATORY LICENSE;ASSIGNOR:NORTHEASTERN UNIVERSITY;REEL/FRAME:026833/0723

Effective date: 20110818