US20030203504A1 - Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species - Google Patents

Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species Download PDF

Info

Publication number
US20030203504A1
US20030203504A1 US10/064,392 US6439202A US2003203504A1 US 20030203504 A1 US20030203504 A1 US 20030203504A1 US 6439202 A US6439202 A US 6439202A US 2003203504 A1 US2003203504 A1 US 2003203504A1
Authority
US
United States
Prior art keywords
diffusion
constituent
chemical species
bio
diffusion channel
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
US10/064,392
Other languages
English (en)
Inventor
John Hefti
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.)
Individual
Original Assignee
Individual
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
Application filed by Individual filed Critical Individual
Priority to US10/064,392 priority Critical patent/US20030203504A1/en
Priority to PCT/US2003/013181 priority patent/WO2003091732A2/fr
Priority to AU2003234271A priority patent/AU2003234271A1/en
Publication of US20030203504A1 publication Critical patent/US20030203504A1/en
Priority to US10/799,000 priority patent/US7713477B2/en
Priority to US12/777,273 priority patent/US20100296973A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5025—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures for parallel transport of multiple samples
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
    • G01N7/10—Analysing materials by measuring the pressure or volume of a gas or vapour by allowing diffusion of components through a porous wall and measuring a pressure or volume difference
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
    • B01L2200/06—Fluid handling related problems
    • B01L2200/0647—Handling flowable solids, e.g. microscopic beads, cells, particles
    • B01L2200/0668—Trapping microscopic beads
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/06—Auxiliary integrated devices, integrated components
    • B01L2300/0627—Sensor or part of a sensor is integrated
    • B01L2300/0645—Electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/06—Auxiliary integrated devices, integrated components
    • B01L2300/0627—Sensor or part of a sensor is integrated
    • B01L2300/0654—Lenses; Optical fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0861—Configuration of multiple channels and/or chambers in a single devices
    • B01L2300/087—Multiple sequential chambers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2400/00—Moving or stopping fluids
    • B01L2400/04—Moving fluids with specific forces or mechanical means
    • B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
    • B01L2400/0472—Diffusion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers 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
    • B01L3/502761—Containers 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 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N2035/00178—Special arrangements of analysers
    • G01N2035/00207—Handling bulk quantities of analyte
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N35/0098—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T436/00—Chemistry: analytical and immunological testing
    • Y10T436/25—Chemistry: analytical and immunological testing including sample preparation
    • Y10T436/2575—Volumetric liquid transfer

Definitions

  • Biologic systems and complex chemical processes such as biochemical pathways, cellular activities, synthetic organic processes, and molecular interactions, (collectively referred to as biologic or chemical activity herein) pose considerable challenges to scientists interested in directly monitoring activities.
  • Such systems usually are rather complex, existing in environments where a number of differing activities are occurring simultaneously, and are thus noisy.
  • Currently, there are a number of general techniques routinely used for detecting biochemical phenomena [David Freifelder, Physical Biochemistry, 1982, second edition, W. H.
  • FIG. 1A illustrates a conventional containment structure for detecting and monitoring biologic or chemical activity.
  • a reservoir 110 e.g., a microtiter well
  • the reservoir 110 may contain, for example, a milliliter or so of a sodium chloride buffer, and at the bottom of the reservoir 110 , a population of cells 113 grow, typically in the range of 50,000 cells or so in total.
  • One milliliter is 10 12 cubic microns, and for a typical cell of radius 20 uM, a population of 50,000 cells gives a total volume of ⁇ 4 ⁇ 10 8 cubic microns.
  • the ratio of volume in the cells to volume in the reservoir is 4 ⁇ 10 8 :10 12 , so that the cells occupy about four-ten-thousandths (4/10,000) of the total volume.
  • FIG. 1B illustrates a common physiological event in the human nervous system: the transmission of electrical impulses along neurons via the modulation of sodium ion channels in the cell membrane.
  • the usual resting state of a cell is to have characteristically low concentrations of sodium internal to the cell, but residing in a buffer with relatively high concentrations of sodium (typically ⁇ 150 millimolar).
  • sodium ion channels on the cell membrane transiently open, and allow passage of the extra-cellular sodium across the membrane, and into the cytosolic fluid (the fluid inside the cell).
  • the present invention now provides systems and methods for detecting and monitoring activity of cellular or molecular species at extremely low quantities using the diffusion processes of, or driven by, the biologic or chemical species.
  • These methods and systems are preferably fabricated in micro-scale systems such as microfluidic and/or photolithograhphically fabricated devices, which can be measurably interrogated in highly parallel fashion.
  • a diffusion-based method for detecting activity of a biologic or chemical species includes supplying the biologic or chemical species to a finite volume diffusion channel having a transport axis.
  • the method further includes supplying a reactive constituent in fluid communication with the biologic or chemical species, whereby the reactive constituent is known or suspected of being reactive to the biologic or chemical species.
  • the method further includes detecting the presence or absence of a diffusion gradient occurring between the biologic or chemical species and the reactive constituent. The presence or absence of the diffusion gradient can then be correlated to the presence or absence of activity of the biologic or chemical species.
  • FIG. 1A illustrates a conventional containment structure for detecting and monitoring biologic or chemical activity.
  • FIG. 1B illustrates the transmission of electrical impulses along neurons via the modulation of sodium ion channels in the cell membrane.
  • FIG. 2 illustrates a first embodiment of the detection/monitoring system in accordance with the present invention.
  • FIG. 3 illustrates one embodiment of a finite volume diffusion channel in accordance with the present invention.
  • FIG. 4 illustrates a process for computing the net amount of biochemical species X between transported between two measurement points in accordance with one embodiment of the present invention.
  • FIG. 5 illustrates an exemplary Na + diffusion response as measured within the detection system of FIG. 2.
  • FIGS. 6 A- 6 D illustrate in succession an exemplary Na + diffusion response propagating along the diffusion channel of the detection system of FIG. 2.
  • FIG. 7 illustrates a process for characterizing fast events in a biologic or chemical system in accordance with one embodiment of the present invention.
  • FIG. 8 illustrates a second embodiment of the detection/monitoring system in accordance the present invention.
  • FIG. 9A illustrates a massively parallel detection/monitoring system in accordance with the present invention.
  • FIG. 9B illustrates one embodiment of a fluidic/measurement cell 950 shown in FIG. 9A.
  • FIG. 10A illustrates a diffusion channel in accordance with one embodiment of the present invention.
  • FIG. 10B illustrates a diffusion response of the diffusion channel shown in FIG. 10A.
  • FIG. 11A illustrates a funnel-shaped diffusion channel in accordance with one embodiment of the present invention.
  • FIG. 11B illustrates a diffusion response obtained using the diffusion channel geometry of FIG. 1A in accordance with one embodiment of the present invention.
  • FIG. 12 illustrates a multiple bead and measurement stage diffusion channel in accordance with one embodiment of the present invention.
  • FIG. 13A illustrates a method for detecting activity of a bio/chemical species in accordance with one embodiment of the present invention.
  • FIG. 13B illustrates a method for monitoring activity of a bio/chemical species in accordance with one embodiment of the present invention.
  • FIG. 14 illustrates a map for correlating changes in measured conductivity to cellular activity in accordance with the present invention.
  • biological or chemical species refers to structure whose biologic or chemical activity is primarily sought.
  • the bio/chemical species refers to any chemical or biologic structure, including, but not limited to: small molecules such as organic and inorganic chemical compounds, proteins and peptides, lipids, nucleic acids, polysaccharides, ionic species, cofactors, synthetic compounds of molecular weight less the 500D intended for therapeutic purposes, other endogenous structures such as hormones, signaling peptides, neurotransmitters; larger biologic structures such as proteins, lipids, polysaccharides, antigens and antibodies, protein receptors and signaling structures, nucleic acids, larger proteins and protein complexes such as ion channels, other membranous protein structures, cell membranes, intracellular structures such as endoplasmic reticulum and organelles, prokaryotic and eukaryotic cells, yeast and fungi, ordered and random populations of cells, tissues comprised of cells obtained from living and
  • the term “reactive constituent” refers to a biologic or chemical structure which is known, or suspected of being reactive with the bio/chemical species, defined above.
  • the reactive constituent may comprise a molecule which is known or suspect of having a binding affinity thereto.
  • the reactive constituent may comprise a small molecule which binds to the cell, or another constituent which is metabolized or otherwise alters the cells function.
  • Examples of the forgoing include, but are not limited to: ionic species, molecules within the cell which are involved with metabolic activities, such as nutrient catabolic or anabolic processes; intermediate molecular constituents in a biochemical pathway, including regulatory molecules and signaling molecules; signaling molecules, such as neurotransmitters and hormones, as well as other peptidic and non-peptidic organic compounds; small molecules intended for therapeutic purposes, such as drugs and other molecules known or suspected of being biochemically active in a given cell population, and the like.
  • metabolic activities such as nutrient catabolic or anabolic processes
  • intermediate molecular constituents in a biochemical pathway including regulatory molecules and signaling molecules
  • signaling molecules such as neurotransmitters and hormones, as well as other peptidic and non-peptidic organic compounds
  • small molecules intended for therapeutic purposes such as drugs and other molecules known or suspected of being biochemically active in a given cell population, and the like.
  • the term “source constituent” refers to the mobile biologic or chemical structure which diffuses toward a “sink constituent”, the term “sink constituent” referring to a biologic or chemical structure which takes up, metabolizes, absorbs, or otherwise reacts with the source constituent.
  • the bio/chemical species or the reactive constituent may each function as the source constituent in different embodiments under the present invention.
  • the bio/chemical species being studied consists of a small molecule (source constituent) which diffuses toward a protein receptor (the reactive constituent and sink constituent).
  • the bio/chemical species studied is a cell operating as a sink constituent, the cell taking up sodium ions from a supply of sodium chloride which functions as the source constituent and the reactive constituent.
  • the terms “finite volume diffusion channel” or “diffusion channel” refer to an enclosed or unenclosed structure configured to contain a fluid volume which ranges between 1/100,000 th to 2,000 times the aggregate displaced volume of the sink constituent.
  • the sensitivity in the measured diffusion rate will be inversely proportional to volumetric ratio of the diffusion channel/sink constituent.
  • the diffusion channel will contain a volume within the following ranges expressed in terms of the aggregate displaced volume of the sink constituent: between 1/100,000 th to 1/10,000 th ; 1/10,000 th to 1/1,000 th ; 1/1,000 th to 1; 1 to 10; 10 to 100; 100 to 1000; and 1000 to 2000.
  • the term “activity” refers to biologic, chemical, or biochemical activity of the aforementioned bio/chemical species, some non-exhaustive examples being the pairwise binding of two biologic or chemical species such as occur in the binding of a small molecule to a protein receptor; the binding or interaction of three or more biologic or chemical species, such as occur in the binding of protein complexes; more complex serial or parallel interactions of any number of biologic or chemical species, such as occur in biochemical pathways for the metabolic and signaling activities in biologic systems; chemical binding and reactions, such as enzymatic catalysis, oxidation-reduction reactions, chemical signaling though hormones or chemokines, and other types of chemical reactions; other types of biologic activities, such as neuronal signaling via membranous ion channel opening and closing; anabolic activities such as protein synthesis and expression, nucleic acid synthesis and expression; assembly and fabrication of more complex biologic structures such as the cytoskeleton, membrane-resident protein association and transport, cellular and organelle replication; and morphologic activities,
  • the term “diffusion” refers to the process by which the source constituent moves from one location to another, usually via some prescribed thermodynamic properties such as temperature, concentration, chemical potential and gradients therein, as well as geometric properties such as length and cross-sectional area.
  • a difference in concentration of the source constituent is introduced between at least two points within the diffusion channel, and the diffusion of the source constituent between these two points is detected and/or measured.
  • a source constituent and a sink constituent are provided in fluid communication with the diffusion channel, and the diffusion of the source constituent within or through the diffusion channel is detected and/or monitored.
  • the present invention is not limited to detecting/monitoring concentration gradients as a means to monitor activity of bio/chemical species.
  • gradients in other quantities such as temperature, pressure, pH, chemical potential, charge, viscosity, density, color, absorption or emission spectra, polarization, biochemical, radiometric quantities, enzymatic activity, nucleic acid hybridization, molecular binding rates or affinities, and the like may be alternatively used as a means to monitor activity of the bio/chemical species under study.
  • the term “transport axis” refers to the axis of the finite volume diffusion channel along which the source constituent migrates or is transported. In one embodiment, the transport axis consists of the major axis of the finite volume diffusion channel. In another embodiment, the term “transport axis” notwithstanding its singular spelling, comprises two or more axes, along which the source constituent diffuses.
  • the term “electrical signal(s)” or electrical measurement(s)” refers to a time-varying (ac) or time-invariant (dc) signal, the former operating over at any useful and measurable frequency.
  • a time-varying electrical signal extends over the Low frequency (LF) to millimeter-wave frequency range (1 KHz-100 GHz).
  • the time varying electrical signal extends into the conventional optical spectrum, e.g., in the range of 7000 to 4000 Angstroms . Time varying electrical signals occurring at both higher and lower frequencies may be used in additional embodiments of this invention, including x-ray frequencies.
  • signal coupled refers to the condition in which the described elements permit an electrical signal to be communicated therebetween.
  • signal coupling may occur between directly contiguous structures, as well as non-contiguous structures having one or more intervening elements.
  • signal coupling may occur either through the direct contact of the described elements, or between elements not in physical contact through electrostatic, magnetostatic, or electromagnetic coupling.
  • the electronic embodiments of these structures are capable of addressing and conveying signals to very small spatial regions, as well as to create topologically complex circuits of very high density.
  • Application of micro-fabrication techniques has enabled the capture and management of very small fluid samples in microfluidic structures, in which both dissolved and non-dissolved biologic and chemical constituents may be manipulated.
  • active transport and passive diffusion collectively referred to as diffusion
  • diffusion active transport and passive diffusion
  • the aforementioned capabilities can be used to provide platforms in which complex biologic and chemical systems can be simulated, prepared, managed, detected, and monitored, all in a highly parallel manner.
  • the result is a collective ability to carry out very complex experiments on biologic and chemical systems, monitor the progress and conditions of the experiment, and to measure useful data on a variety of experimental parameters.
  • Diffusion refers to a process by which some quantity either matter or energy moves from one location to another, usually via some prescribed thermodynamic properties such as temperature and concentration, as well as geometric properties such as length and cross-sectional area.
  • thermodynamic properties such as temperature and concentration
  • geometric properties such as length and cross-sectional area.
  • j is a vector describing the flux density of the quantity which is diffusing (such as heat or molecules)
  • f is a function describing the physical property responsible for driving the diffusion process (such as gradients in temperature or concentration of molecules)
  • D is the constant of proportionality, called the diffusion coefficient, or diffusivity.
  • the first of these equations may be used.
  • the second of these equations is used.
  • boundary conditions refer to the values of the function f at specific points or regions within the system being modeled.
  • a particular geometry such as a rectangular box, or a cylinder
  • Initial conditions refer to the state of the system at some pre-defined starting point. In many cases, one does this by specifying the value of f at every point in the system at some initial time t.
  • Important special cases include the situation in which there is no time-dependence, the so-called steady state where the function f does not depend explicitly on time. In this case, one is usually interested in modeling the transport of some particular quantity in the system form one region to another.
  • a second special case is where one is interested in modeling the approach to equilibrium. In this case, initial conditions are specified (along with diffusion constants and geometry), and the system is allowed to evolve until the steady state is reached.
  • Diffusive processes such as heat flux, or the transport of chemical species down a concentration gradient, is driven by many factors, such as concentration, temperature, viscosity, characteristic dimensions and shapes of the system, as well as sources (elements which add a particular quantity to the system) and sinks (elements which subtract a particular quantity from the system). In the latter case, one has to modify the diffusion equation to include source and sink terms.
  • the presence and/or rate of diffusion which indicates biologic or chemical activity, is measured through the use of electrical signals.
  • the parameter of conductivity may be used to electrically sense the presence and rate of diffusion.
  • Electrical conductivity refers to the capability of a given material to carry an electrical current, either in the form of a direct current (DC), or an alternating current (AC). Conductivity is described by the following equations:
  • the first of these equations is a form of the diffusion equation, in which the quantity being transported is electrical charge, and the driving function is the gradient of the electrical potential, or voltage.
  • j is the current density
  • E is the electric field
  • ⁇ is the conductivity (which is essentially the diffusion constant for this special case.)
  • the conductivity is the sum over all charge carriers with respect to their concentrations n, absolute value of the net charge q, and mobility ⁇ .
  • the mobility is defined to be the average velocity of a charge or charge carrier, divided by the average electric field acting on the charge or charge carrier.
  • conductivity is used as an indication of concentration in several exemplary embodiments described herein, the reader will appreciate that other electrical parameters such as resistivity or resistance, voltage, current, phase, impedance, inductance, capacitance, permittivity, permeability and the like may also be used as an electrical measurement parameter to detect changes in concentration, and accordingly, the presence or rate of activity of the bio/chemical species under investigation.
  • biochemical process refers to a variety of biological behavior at the chemical level, including, but not limited to: enzymatic catalysis of reactions involving metabolic reactants and products, the transport of specific chemical species from one region in the cell to another (such as across the cell membrane), signaling processes such as occur in hormonal responses, or the transport of neurotransmitters across the synaptic cleft causing the initiation of signal propagation along neurons.
  • biochemical pathway refers to two or more individual reactions in series, resulting in a sort of chain-reaction or cascade of biochemically-mediated events.
  • Pathways in biologic systems often consist of a very long series of biochemical processes, with a host of regulatory components, branch points (where derivative pathways bifurcate), all functioning in a manner which may be highly non-linear.
  • a property of biochemical events is that they usually occur in a spatially distributed manner. For example, an increase of a particular constituent in a system at one place requires (for purposes of satisfying conservation laws) that the constituent be depleted at some other region.
  • a good example is ion flux across a cell membrane: extra-cellular stores of a particular ion are depleted and intra-cellular stored are enhanced, in the event that there is a net flux of the ion into the cell.
  • the behavior is made use of in the present invention to detection monitoring activity of biologic or chemical species as will be illustrated below.
  • the monitoring system of the present invention utilizes a diffusion channel of limited volume in which measurement signals of various modalities are used to monitor the presence and/or rate at which a diffusion gradient is established between at least two points along the diffusion channel.
  • the particular measurement modality electrical, photonic, radiometric, enzymatic, fluorescent, calorimetric, etc.
  • the parameter monitored can be varied, the only requirement being that the measurement probe used is configured to support the propagation and/or receipt of the particular signal being implemented.
  • Diffusion occurs between a source constituent and a sink constituent which are in fluid communication with each other.
  • the source constituent moves toward the sink constituent through the finite volume diffusion channel, producing a concentration gradient which can be detected and/or measured.
  • the activity of the source constitute can be ascertained.
  • knowledge of the biologic or chemical makeup of the source constituent and the aforementioned presence (or absence) and source constituent's rate of diffusion, conclusions as to the activity of the sink constituent can be made.
  • the bio/chemical species whose activity is the subject of investigation may function as the source constituent or the sink constituent.
  • the subject bio/chemical species may function as both a source constituent and a sink constituent during different phases of an experiment.
  • a subject cell operating as a sink constituent is activated upon receiving a reactive constituent, the cell's activity detected and monitored by the diffusion of the reactive constituent through the diffusion channel.
  • the cell upon activation, emits a structure which becomes a source constituent during the second phase of the experiment, the source constituent diffusing toward and binding to or otherwise reacting with another structure (fixed or mobile) within the diffusion channel.
  • the cell operates as a sink constituent
  • the second phase of the operation the cell operates as the emitter of a source constituent.
  • the presence and degree of a diffusion gradient can be detected between the two or more measurement points using electrical, photonic, radiometric measurement system as well as other modalities (essentially, any measurement which established that something is moving form one region to another).
  • electrical, photonic, radiometric measurement system as well as other modalities (essentially, any measurement which established that something is moving form one region to another).
  • one measurement modality may exhibit superior detection and measurement sensitivity over others. For instance, when attempting to measure a concentration gradient created through the movement of charged or ionized particles, the use of electrical signals may be preferable.
  • physiologic behavior such as molecular interactions and metabolic cellular responses, either to intended stimulation or inhibition, or responses to stimuli that were not a priori known to have effects, are measurable through the effect they have on the extra-cellular medium in which they reside.
  • response of cells or molecules can be directly monitored through the effect that a given sample volume has on the propagation of a signal.
  • a photonic measurement apparatus will be preferred to determine concentration gradients.
  • concentration gradients are not limited to the use of any one measurement modality and that others may be used in alternative embodiments of the present invention.
  • properties other than concentration e.g., temperature, pH, etc.
  • FIG. 2 illustrates a first embodiment of the detection/monitoring system 200 in accordance with the present invention.
  • the system 200 includes a source reservoir 220 , a sink reservoir 230 , and a diffusion channel 240 connected between the sink and source reservoirs 220 and 230 .
  • the system 200 is constructed as a microfluidic structure using fabrication techniques known in that art.
  • a passive transport system is used in which the source constituent 222 migrates toward the sink constituent 232 resident in the sink reservoir 230 .
  • the source reservoir 220 is configured to contain a source constituent 222 , which in this exemplary embodiment comprises sodium ions.
  • the sink reservoir 230 is operable to contain the sink constituent 232 , which also consists of sodium ions, the sink reservoir having a lower concentration thereof.
  • other source and sink constituents may be used to detect activity in other bio/chemical species in alternative embodiments within the present invention.
  • the finite volume diffusion channel 240 operates as a gradient bridge between the source and sink reservoirs 220 and 230 and includes a transport axis 242 , along which the source constituent 232 diffuses.
  • the diffusion channel 240 has one major axis (length) which defines the transport axis 242 .
  • the diffusion channel 240 includes at least one additional major (or near major) axis (width and/or height) which permits diffusion therealong.
  • measurement probes are located to measure diffusion along these additional major axes.
  • the diffusion channel 240 further includes a plurality of (i.e., two or more) measurement probes 244 disposed along the transport axis 242 .
  • the measurement probes 244 are operable to detect the diffusion rate of the source constituent as it migrates along the transport axis 242 .
  • a change in the diffusing quantity's concentration is measured, although other properties such as temperature, pressure, pH, etc. may be used in alternative embodiments within the present invention.
  • one or more measurement probes 244 are positioned to measure concentrations within the source and/or sink reservoirs 220 and/or 230 .
  • the measurement probes 244 may be either in direct contact with the solution flowing along the transport axis 242 , or the probes 244 may be designed to electromagnetically coupled a signal to/from the solution as it flows along the transport axis 242 . In such cases, the measurement probe need not be in direct contact with the solution.
  • the present invention is not limited to electrical/electronic means of interrogation.
  • Other measurement modalities such as photonic, radiometric, or biochemical (e.g., in the form of immunoassays) may be used to detect and/or monitor the diffusion process occurring along the transport axis 242 .
  • the sink and source constituents 222 and 232 may be one of any known components.
  • the sink constituent 232 may contain the same component (sodium) as present in the source constituent 222 , except in lower concentration.
  • the sink constituent may consist of cells which metabolize or otherwise consume the sodium, thereby causing sodium to diffuse toward the sink reservoir 230 along the transport axis 242 . Consequently, a sodium diffusion gradient is set up along the transport axis 242 , the presence of which can be detected and monitored using measurement probes 244 .
  • the measurement probes use electrical signals (ac or dc) to measure electrical parameters, such as conductance, at two or more lateral positions.
  • Differences in the measured conductance along the transport axis will indicate that diffusion is occurring and that the cell population in the sink reservoir is actively taking up the Sodium.
  • Other electrical parameters such as resistance, voltage, current, capacitance, inductance and the like may be used alternatively.
  • Other measurement modalities such as optical, radiometric, or biochemical measurement techniques may be used alternatively or in addition to interrogate the measurement probes to provide detection and monitoring information.
  • the time evolution of the system favors a tendency toward equilibrium, in which the concentration of sodium in the sink reservoir 230 is equal to the concentration of sodium source reservoir 220 .
  • concentration of sodium in the sink reservoir 230 is equal to the concentration of sodium source reservoir 220 .
  • the rate of this transport is given by solving the diffusion equation under the initial conditions of concentration as a function of position, and the geometry of the diffusion channel 240 .
  • the latter dependence is characterized by the cross-sectional area and length of the diffusion channel 240 connecting the source and sink reservoirs 220 and 230 .
  • l is the length between the measurement probes, and A is the cross-sectional area.
  • the constant of proportionality C is determined empirically, using solutions of known concentrations or conductivities.
  • the flux of sodium ions down the transport axis 242 can be monitored via monitoring the conductivity.
  • the multiple measurement probes 244 enable one to determine the gradient of the concentration, by simply determining the concentration at each of the points of detection, and knowing the distance between them. From this data, and the use of the diffusion equation already described, the net flux from one reservoir to another can be determined as a function of time.
  • FIG. 3 illustrates one embodiment of the finite volume diffusion channel 240 having length L in accordance with the present invention.
  • the length L is much greater than the width or height.
  • the diffusion process becomes one-dimensional and can be modeled easily using the aforementioned diffusion equation.
  • one of the other dimensions is enlarged to approach or equal the structure's length.
  • diffusion occurs across a two-dimensional plane, and the aforementioned diffusion equation can be solved in two dimensions, leading to a richer understanding of the biologic or chemical activity occurring.
  • the boundary conditions at the two measurement points, along with the regular geometry of the diffusion channel 240 between measurement points (here assumed to be a rectangular box with uniform cross-sectional area A) and the diffusion constant D, provides the current density j throughout the system.
  • the net transport Q of the bio/chemical species X between boundary points is determined.
  • more complex geometries may be used, and time variation on the boundary condition can also be accounted for, using straight-forward extensions of the techniques used in this simple example.
  • FIG. 4 illustrates one embodiment of the aforementioned process for computing the total amount of bio/chemical species transported between two measurement points.
  • a diffusion channel is provided in which at least two measurement points z 1 and z 2 are provided, the measurement points z 1 and z 2 being separated by a dimension L.
  • the change in relative concentration of the bio/chemical species X between measurement points z 1 and z 2 is determined, a process by which can be performed using the systems and methods described herein.
  • the change in relative concentration of X between measurement points z 1 and z 2 can be obtained by using the described system to measure a change in the species” conductivity, and subsequently correlating that change to a change in concentration.
  • different measurement modalities may also be used to detect/measure a change in the species” concentration.
  • the channel's cross-sectional area A between measurement points z 1 and z 2 is determined.
  • This quantity may either be known from the fabrication specifications of the channel or measured (for example, though the use of a solution with known diffusion properties and concentrations, applied to the system described) if the dimensions are not known. In an alternative embodiment, either of the other three variables may be determined if the remaining variables are known.
  • the diffusion coefficient D of the particular bio/chemical species is determined.
  • this quantity is determined by measuring the diffusion rate of the bio/chemical species in an apparatus in which the geometry well-known and the concentrations are accurately measured. Such measurements may be made before, during, or after the process being described herein.
  • activities of interest such as molecular binding or other biologic or chemical responses
  • the isolated diffusion properties may be evaluated by providing well-specified geometries of the fluidic system, and accurate concentrations of the biologic or chemical species, then measuring the diffusion rate of the species in the system.
  • the result of such an experiment would be the determination of the diffusion constant, which would subsequently allow for the quantitation of the total transport of the species in the previous experiment. Of course, one could do the same procedure before an experiment as well.
  • the total amount of species transported is determined by calculating the quantity: DA ⁇ [ [ X 2 ] - [ X 1 ] L ]
  • the concentration gradient is a function of the difference in the two measured concentrations , as well as the linear distance L therebetween.
  • the distance L can be shortened (still assuming fixed boundary conditions), and/or the concentration difference at the two boundaries can be increased.
  • the above diffusion equation can be accurately approximated by a one-dimensional model, with relatively simple boundary conditions. Using this model, one can then calculate the value for the difference in the concentrations between the boundaries, given a measured value for the gradient; or if the concentrations at one of the two endpoints is known (for example, by direct measurement, or by being prepared in some known way), then given the measured gradient, we can measure the absolute value of the quantity at the other boundary. In addition, these relationships can be used to calculate the total transport of material or energy from one region to another.
  • systems like these can, among other purposes, serve as a calibration standard. For example, suppose one seeks to monitor the overall metabolic activity of a given set of samples, and use this as a reference by which other activities can be standardized. In this case, one simply places an excess of an essential nutrient in the test reservoir, excess meaning that there is far more of this nutrient than the sample population of cells can utilize in the course of the experiment and measures the gradient across the diffusion channel to determine the net flux of this nutrient from the reservoir to the cell population. As an extreme example, it is clear that a population of dead cells would not use any of the nutrient, and thus the gradient would be less steep (or even flat, at equilibrium) than a population of live, healthy cells.
  • “slowly varying” means that the concentration gradient in the diffusion channel has sufficient time to adjust to changes in the boundary conditions that it remains near equilibrium; the gradient is constant at any time during the experiment, but may change slope throughout the experiment. In this case, the problem may be reduced to solving the equilibrium situation, as described in case 1, for different values of the boundary conditions at different times (a so-called “piece-wise linear” situation).
  • the time variance behaves as a simple exponential function, whose time constant may be made arbitrarily large by the appropriate choices of the cross-sectional area A and the length L . Both of these properties can be used to normalize data, as well as to separate simple diffusion-driven transport processes from true sources and sinks.
  • a filter for events on different time scales can be generated. For example, suppose the ion channel activities in the range of 100 msec are of interest only, excluding the slower drift or diffusion events in the cell. A system can be constructed, by choosing the cross-sectional area and length such that the diffusion process being studied occurs on a timescale consistent with a desired temporal window of observation. Thus, with the appropriate geometries, slow events (such as simple diffusion out of the test reservoir and into the sample reservoir) yield piecewise-equilibrium type behavior, but faster events do not.
  • Case 3 f( x,t) at the boundaries is a rapidly varying function of time.
  • “rapidly varying” means that the concentrations and gradients therein do not have time to reach a new equilibrium on the time scale of the fluctuations in f at the boundaries.
  • the full spatial and temporal dependence of the concentration is preferably taken into account between measurement points along the diffusion channel.
  • FIG. 5 illustrates an exemplary Na + diffusion response as measured within the detection system of FIG. 2.
  • a small population of cells is immersed in a standard buffer solution with ⁇ 150 millimolar sodium chloride.
  • FIG. 7 illustrates one embodiment of the aforementioned process for computing a diffusion response profile.
  • a diffusion channel is provided in which at least two measurement points z 1 and z 2 are provided, the measurement points z 1 and z 2 being separated by a dimension L.
  • a first diffusion response profile is obtained, the first profile representing the change in relative concentration of the bio/chemical species X between measurement points z 1 and z 2 is determined at time t 1 .
  • This process can be performed using the systems and methods described herein.
  • the change in relative concentration of X between measurement points z 1 and z 2 can be obtained by using the described system to measure a change in the concentration's conductivity, and subsequently correlating that change to a change in concentration.
  • different measurement modalities may also be used to detect/measure a change in the species concentration.
  • a second diffusion response profile is obtained, the first profile representing the change in relative concentration of the bio/chemical species X between measurement points z1 and z2 is determined at time t2.
  • a complete diffusion profile is assembled by combining the first and second diffusion profiles.
  • additional diffusion profiles in which the differential concentration change is made at times t 3 -t n may be made and combined to provide the complete diffusion response.
  • the combined diffusion response can be stored and retrieved to compare to a later diffusion process in order to identify it.
  • FIG. 8 illustrates a second embodiment of the detection/monitoring system 800 in accordance the present invention.
  • the system 800 includes a voltage source 802 , resistors 804 , and a voltmeter 806 in addition to the previously described diffusion channel 240 and measurement probes 244 a and 244 b .
  • probes 244 a and 244 b each include a high side probe ( 244 a 1 and 244 b 1 ) and a low side/ground probe ( 244 a 2 and 244 b 2 ).
  • the sink constituent in the instant system 800 is deposited within an interaction region 820 , preferably located between measurement probes 244 a and 244 b .
  • the invention is not limited to the use of two-member probes, and “single” probe conductors such as wire, optical fiber, or waveguides, may be used in alternative embodiments within the present invention.
  • the voltage source 802 and resistors 804 are removed and voltmeter 806 is replaced by an ohm meter to passively measure the differential resistance occurring between measurement probes 244 a and 244 b.
  • the monitoring/detection system 800 is designed to detect/monitor the diffusion rate through sensing a difference in the measured conductance of probes 244 a and 244 b .
  • a first voltage 802 to each high side probe member 244 a 1 and 244 b 1 through resistors 804 source constituent flow is assumed left to right.
  • the probes and resistors are photolithograhphically formed, and accordingly exhibit little or no difference in resistance.
  • the first and second measurement probes 244 a and 244 b will measure the source constituent's concentrations before and after the sink constituent, respectively, a difference indicating that a reaction, e.g., the sink's uptake of the source, has occurred.
  • the probe having the comparatively highest local conductance between its high and low side elements will sink the larger amount of current compared to the probe having a lower conductance . Accordingly, a voltage difference between the two probes will be developed, the magnitude and direction of the voltage difference (monitored by voltmeter 806 ) being indicative of the magnitude and direction of the diffusion process occurring.
  • additional measurement probes 244 may be positioned along the transport axis to detect or monitor smaller changes in the diffusion rate.
  • the fluidics and signal measurement systems may be integrated together on the same platform.
  • the diffusion rate may be detected or monitored by applying and monitoring a time-varying voltage taken at each of the probe positions 244 .
  • probes 244 would consist of connectors (or waveguides, depending the operating frequency) operable to support the propagation of the desired ac signal (low side measurement probes 244 a 2 and 244 b 2 would be connected to an ac ground, which may not be dc ground).
  • Voltage source 802 would consist of an ac signal source operating at the desired frequency and amplitude
  • resistors 804 would be resistors or attenuators (depending upon the operating frequency)
  • voltmeter 806 would consist of an ac voltmeter.
  • the voltage source 802 and resistors 804 are removed deleted and voltmeter 806 is replaced by an ohm meter to passively measure the differential resistance occurring between measurement probes 244 a and 244 b .
  • Electrical parameters other than conductance and resistance e.g., voltage, current, inductance, capacitance, etc. may be used in alternative embodiments within the present invention.
  • the aforementioned measurement system could be fabricated as part of a micro-miniature, massive parallel system using know processes such as hybrid integrated circuit processes, monolithic integrated circuit processes, micro-electromechanical systems (MEMS).
  • the fluidics of such a system may consists of a microfluidic system which is combined (e.g., monolithically integrated, or separately fabricated and attached) with the measurement system.
  • the aforementioned system may also be implemented in an optically-based measurement system.
  • the diffusion rate of the source constituent which contains, or is itself optically opaque may be detected by monitoring the optical intensity of a reflected signal at each of the probe positions 244 a and 244 b , a lower intensity (or different wavelength) being indicative of a higher concentration at that particular measurement probe.
  • measurement probes 244 are fiber pigtails or other optically transparent probes configured to support the propagation of an optical signal at the desired wavelength.
  • the volt source 802 would be an optical source
  • resistors 804 would be optical attenuators of substantially the same value
  • voltmeter 806 would consist of an optical intensity meter.
  • the aforementioned optical source and attenuators may be deleted and the optical intensity meter may be replaced with an optical wavelength meter to measure the difference in wavelength emitted at the two measurement probes.
  • Optical parameters other than intensity and wavelength e.g., solution transparency
  • the fluidics of such a system consists of a microfluidic system which is combined (e.g., monolithically integrated, or separately fabricated and attached) with the measurement system.
  • Microfluidic systems such as those formed from the multi-layer soft photolithography process employed by the Fluidigm Corporation of South San Francisco, Calif., etched glass processes as employed by Caliper Technologies, Inc. of Mountain View Calif., and polymer plastic processes as employed by Aclara Biosciences, Inc. of Mountain View, Calif. may be used in embodiments of the present invention.
  • FIG. 9A illustrates a massively parallel detection/monitoring system 900 in accordance with the present invention.
  • the detection/monitoring system 900 includes N vertical fluid channels and M horizontal channels, each channel intersection forming a fluidic/measurement cell 950 .
  • the system 900 may consist of any parallel-arranged combined fluidic/measurement system, not excluding the aforementioned microfluidic, hybrid, monolithic, or MEMS systems, described herein.
  • FIG. 9B illustrates one embodiment of a fluidic/measurement cell 950 in accordance with the present invention.
  • each cell 950 includes a horizontal flow channel 952 , a vertical flow channel 954 , and a cavity 956 operable to capture beads 959 introduced into the cell through vertical channel 954 .
  • Beads 959 operate as the sink constituent and contain either the bio/chemical species under study or the reactive constituent which is known or suspected of being reactive to the bio/chemical species under study.
  • the bio/chemical species or reactive constituent are deposited on beads using conventional means know in the art of biology and chemistry, and the beads 959 may be composed of paramagnetic or non-ferrous material as known in that art.
  • the horizontal axis of cell 950 defines the transport axis, along which measurement probes 244 a and 244 b are disposed.
  • the source constituent is provided through the input 952 a , across the first measurement probe 244 a , across one or more of the beads, across the second measurement probe 244 b and to the channel output 952 b .
  • measurement probes 244 are connected to resistors, a voltmeter, and a voltage source as shown in FIG. 8.
  • each cell is singularly addressable to provide a voltage signal thereto and to receive a voltmeter reading therefrom.
  • the beads 959 are supplied to cell 950 via vertical channels 954 , one or more beads 959 collecting in the cavity 956 .
  • the source constituent is supplied to the horizontal channel input 952 a .
  • the source constituent has a baseline, i.e. “unaffected” concentration as it passes across the first measurement probe 244 a .
  • the concentration may change if it reacts with the material (bio/chemical species or reactive constituent) attached to the surface of the bead 959 .
  • the solution passes across the second measurement probe 244 b having a different concentration, the difference in concentration present between the first and second probes 244 a and 244 b being sensed and indicating the presence (or absence) and/or rate of activity in the bio/chemical species.
  • the vertical fluidic channel 954 connects to each of the M vertically oriented cells, allowing beads 959 to be supplied to each of those cells.
  • a parallel measurement process may be performed in which M different source constituents may be supplied to each M input.
  • each cell may be addressed and interrogated to determine whether, and/or to what degree an interaction between the bead material and the particular source constituent is occurring.
  • each of the horizontal fluidic channels 952 connects to each of the N horizontally oriented cells, allowing the supplied source constituent to travel through each of these cells.
  • each of the N vertically oriented fluidic channels 954 are supplied with beads having different attached material. Accordingly, activity of each of the M source constituent can be analyzed with respect to N different bead-based materials as each source constituent horizontally flows through each of the N cells. As described above, each of the cells may be individually addressed and interrogated in order to detect/monitor activity within them.
  • the finite volume diffusion channel of the present invention may be constructed of various cross-sectional areas in order to provide further detection and/or monitoring benefits.
  • FIGS. 10 - 12 illustrate some of these embodiments.
  • FIG. 10A illustrates a portion of the diffusion channel 240 located between measurement probes 1030 (not shown), the diffusion channel portion having beads 959 and a bead flow restrictor 1010 in accordance with one embodiment of the present invention.
  • the number of beads 950 , flow rate, and dimensions of the diffusion channel can be selected such that desired diffusion response is obtained. Specifically, the source constituent flow rate, the length of the bead region 1020 , and distance to the measurement region 1030 , along with the total quantity of the target molecule within the bead region 1020 binding region and relative affinities, will determine when saturation occurs, and thus the binding kinetics as discussed below.
  • the bead flow restrictors 1010 may be any permanent or temporarily means to confined/restrict the flow of bead therethrough, including the application of a magnetic field to temporarily restrict the flow of paramagnetic beads.
  • Flow restriction may be accomplished through electrophoretic or dielectrophoretic separation techniques, as are well-known in the art.
  • Chemical preparation of the bead surfaces may include any of the well-known techniques (such as Au-thiol chemistries, or silane chemistries) for derivatizing surfaces with specific linker and attachment chemistries, for the purposes of attracting and retaining molecules, molecular structures and complexes, as well as cellular extracts, cells and tissues.
  • FIG. 10B illustrates a first diffusion response of the diffusion channel 240 shown in FIG. 10A. This response indicates the difference of Q when the solution passes through the bead region 1020 , as a function of time. In the absence of any interaction or binding, or for any equilibrium process, this difference is necessarily zero.
  • FIG. 11A illustrates a funnel-shaped diffusion channel 240 having beads 950 and a bead flow restrictor 1010 in accordance with one embodiment of the present invention. This embodiment facilitates the measurement of a fast diffusion response occurring within the interaction region 820 .
  • the width of the diffusion channel 240 By constricting the width of the diffusion channel 240 , it is extended in length (by an amount roughly equal to the inverse fraction of the diminution of width), so that diffusion to equilibrium takes much longer (due to the increased diffusion length), and the spatial extent of the solution with altered values of Q is extended, facilitating the measurement process.
  • FIG. 11B illustrates an optimal diffusion response obtained using the diffusion channel geometry of FIG. 11A.
  • the response includes a falling edge 1132 and a rising edge 1134 which are within the time scale of the graph.
  • other geometries may be used to capture the particular diffusion response sought.
  • unwanted diffusion responses which are either faster (having a relative fast fall and rise time) or slower (having a longer fall and rise times), may be filtered out from the detection/monitoring process by means designing the physical dimensions of the diffusion channel accordingly.
  • FIG. 12 illustrates a multiple bead and measurement stage diffusion channel 1240 in accordance with one embodiment of the present invention.
  • the diffusion channel 1240 includes multiple stages of interaction regions 820 consisting of beads 959 and bead blockers 1010 , each region 820 followed by a measurement probe 244 . This configuration is useful for making serial analyses of a single source constituent with multiple sink constituents.
  • the detection/monitoring system of the present invention includes a fluidic system and measurement system which may be integrally formed or separately fabricated and attached.
  • the fluidic system includes all of the structural and mechanistic apparati operable to isolate and transport samples of fluid, along with non-fluid constituents residing therein, in the invention described herein. This structure may be fabricated using any of the well-known techniques in the art.
  • Examples include, but are not limited to: hard or soft lithographic methods employing single or multiple layer materials (glass, plastics, polymers such as PDMS, synthetic and natural rubber, and other terpene-based matrices); mechanical methods of fabrication, such as micromachining of rigid and supple materials, using for example well-known micro-electrical mechanical systems (MEMS); the use of capillaries and other such conduits well-known in the art, as well as arrays of such structures when used in a multiplex fashion. Structures designed for fluid containment and transport may also be imbedded in larger systems, such as microtiter plates and wells, as are commonly used in wet lab applications.
  • MEMS micro-electrical mechanical systems
  • the measurement system preferably includes all of the apparati operable to detect/monitor a signal originating from the interaction of the source and sink constituents.
  • the measurement system additionally includes apparati (such as signal sources and connecting circuitry) to provide an incident signal to the source constituent flowing through the diffusion channel, and in other embodiments the measurement process is passive and does not require transmitting a signal to the measurement probes.
  • the measurement system may be fabricated using MEMS techniques, semiconductor or photolithographic processing techniques, or other fabrication techniques known in the measurement modalities disclosed herein.
  • FIGS. 13A and 13B illustrate, respectively, methods for detecting and monitoring activity of a bio/chemical species in accordance with one embodiment of the present invention.
  • the activity detected includes biologic, chemical, or biochemical activity as defined herein.
  • each method includes several processes, the sequence of which may vary in alternate embodiments within the present invention.
  • the subject bio/chemical species under study is supplied in fluid communication with a finite volume diffusion channel as described herein.
  • the bio/chemical species may be located within the diffusion channel, or outside of the channel within a reservoir that is fluidly connected to the diffusion channel. In the latter case, one or more fluid conduits constructed in a microfluidic or other micro-miniature structure referred to herein may be used.
  • a reactive constituent which is known or suspect of being reactive with the subject bio/chemical species, is supplied in fluid communication with the finite volume diffusion channel. As discussed herein, either the subject bio/chemical species or the reactive constituent may operate as the mobile source constituent.
  • a diffusion response occurring between the bio/chemical species and the reactive constituent is detected along the transport axis of the diffusion channel. This process is preferably accomplished by detecting a differential source constituent concentration occurring between two or more measurement probe positions, as described above.
  • the diffusion response may be made at set time t 1 , over a continuous time period t 1 -t 2 , or at discrete times t 1 , t 2, . . . t n .
  • the detected diffusion response is correlated to the presence or absence of activity of the bio/chemical species.
  • the diffusion response detected in 1306 is compared against a baseline diffusion response in which the source constituent normally diffuses in the absence of the sink constituent.
  • the baseline response may be obtained using the same fluidic and detection system, but which lacks a sink constituent.
  • the baseline diffusion processes in this structure can be detected and stored, for later comparison with one or more experiments which include a sink constituent.
  • the difference in the measured diffusion properties reflects the effects of the sink constituent.
  • the measured and baseline responses may be obtained substantially concurrently using a parallel measurement system, such as that described in FIGS. 9A and 9B above.
  • FIG. 13B illustrates a method the monitoring of activity of a bio/chemical species in accordance with one embodiment of the present invention.
  • the subject bio/chemical species under study is supplied to a finite volume diffusion channel as described herein. As described above, this process may be performed by the use of fluid conduits constructed in a microfluidic or other micro-miniature structure referred to herein.
  • a reactive constituent which is known or suspect of being reactive with the subject bio/chemical species, is supplied to the finite volume diffusion channel.
  • a diffusion response occurring between the bio/chemical species and the reactive constituent is measured along the transport axis of the diffusion channel. This process is preferably accomplished by measuring the differential source constituent concentration occurring between the two or more measurement probe positions, as described above.
  • the diffusion response may be made at a set time t 1 over a continuous time period t 1 -t 2 , or at discrete times t 1 , t 2, . . . t n .
  • the measured diffusion response is correlated to activity in the bio/chemical species.
  • the diffusion rate measured in 1326 is compared to a baseline source constituent diffusion rate, in which it is know that a particular activity of the subject bio/chemical species is not occurring.
  • the systems and processes discussed with regard to FIG. 13A by which a baseline response is obtained, either at a later time or concurrently with the measured response may also be used.
  • the method of FIG. 4 may be used to determine other quantities of the diffusion equation as described herein.
  • the cross-sectional area A of the diffusion channel (of length L) may be solved for using the equation of FIG. 4 if all of the other variables are known. This could be accomplished, for instance, by measuring the diffusion of a known solution having a well-defined diffusion coefficient D, and computing the total amount transported from the measurement interval.
  • the diffusion coefficient D may be computed if the other variables are known or can solved for independently.
  • reaction vessel meets the previously-described criteria of a finite volume diffusion channel, i.e., the volume of the reaction vessel is not greater than 10,000 times the aggregate displaced volume of the source constituent to be supplied to the vessel.
  • the reaction vessel also includes two or more measurement probes configured to detect/measure the diffusion of the source constituent, through the measurement of electrical means, such as conductivity.
  • a cell population having a known, particular pathway is selected for study.
  • cell populations having particular sodium ion channel behavior is selected.
  • a viable and active population of the desired cells is established within the vessel, perhaps using buffers which are known to support the viability and functionality of the cell population.
  • the conductivity of the system (cells+buffer) is then measured before stimulation, thereby establishing a baseline value.
  • the cell population is stimulated by replacing the existing buffer with an identical buffer with a reactive constituent known to stimulate the pathway.
  • changes in the system's conductivity is monitored while adding the new buffer and a predefined time thereafter. A change in the monitored conductivity values can then be correlated to the cell's activity.
  • FIG. 14 illustrates a map for correlating changes in measured conductivity to cellular activity.
  • Four experiments are made: a first experiment 1401 in which sodium is added to the vessel and the cell's reaction is observed using an other measurement means (e.g., fluorescence); a second experiment 1402 in which the same amount of sodium is added and no change in activity is monitored; a third experiment in which no sodium is added and a change is cellular activity is monitored 1403 ; and a fourth experiment 1404 in which no sodium is added and no change in cellular activity is observed.
  • the results of these experiments can be arranged in a matrix form, the first experiment indicating a positive response of the added sodium. Accordingly, the measured changes in conductivity can then be correlated to the cell's observed activity in later experiments..
  • a system such as that shown in FIG. 10A in which a population of beads is retained within a bead region, each of the beads coated with a specific protein to which small molecules are known or suspected to bin.
  • the beads are isolated to a specific region of the diffusion channel such that the source constituent may emerge downstream.
  • the diffusion channel includes measurement probes situated before and after the bead region.
  • a solution containing the source constituent, a species of molecules or molecular structures which bind target proteins immobilized to the beads When a solution containing the source constituent is introduced to diffusion channel, it will contain a certain concentration of the binding molecules. This concentration is measured before the interaction with the bead-immobilized target, then allowed to pass through the bead region at some determinable rate, and analyzed in the outflow section for the concentration of the molecular species of interest. The result of this measurement, combined with a knowledge of relative concentrations of target and molecule (or total amount of each) as well as the speed at which the solution moves through the bead region (or binding region), will yield the kinetic properties of the system directly.
  • the diffusion response (an embodiment of which is illustrated in FIG. 10B) exhibits a sharp decrease in concentration where the initial quantity of X is removed from solution, a plateau region where the source constituent is being consumed, and a gradual return to the equilibrium value which of necessity is the same value as the solution in the in-flow region, since there is no net loss of the source constituent in the diffusion channel after saturation has occurred.
  • the response exhibits a much more step return to equilibrium as saturation occurs more quickly over this time period.
  • the bead surface represents the sink constituent in one embodiment of the present invention and may include any class of molecular structures, either bound to beads or other surfaces in the binding region, including derivatized and/or functionalized surfaces, polymer matrices or scaffolds, or molecules which reside in membranes such as are found in cellular systems or artificial membranes designed to mimic physiologic membranes; complexes of molecular structures, such as multi-protein complexes, or polymer-attached biomolecules of interest; or cell and/or tissue samples which contain one or more molecular targets of interest, which may bind other molecular structures in the solution; and the like.
  • any class of molecular structures either bound to beads or other surfaces in the binding region, including derivatized and/or functionalized surfaces, polymer matrices or scaffolds, or molecules which reside in membranes such as are found in cellular systems or artificial membranes designed to mimic physiologic membranes; complexes of molecular structures, such as multi-protein complexes, or polymer-attached biomolecule
  • the data obtained from such measurements may be applied in a variety of ways, and used for various purposes. For example, using data to generate gradient and transport properties of source constituents in the experiment which are known or are suspected, of being active, may result in an understanding of biologic activity or activities of the source or sink constituents. In the case of binding of a particular small molecule to a biologic target, as described above, the point in the system where this occurs will result in a local gradient.
  • analyses and uses include, but are not limited to: the transport of metabolically active molecules to specific cells or cell populations, which also will create local gradients, and indicate highly specific types of biologic or biochemical activities; the transport of signaling molecules, such as proteins and peptides, neurotransmitters and hormones, between cells or cell populations, resulting in local gradient changes whose measurement, along with the knowledge of initial conditions of the system will yield knowledge on activity or activities of the molecules; the use of gradients and other measurable changes in system properties (such as conductance or conductivity) as a means to monitor processes in the system, such as flow or tracking of samples within the system, and in addition, the use of this information to supply feedback data to system controllers (such as pumps and measurement devices, and components of the system designed to coordinate these functions).
  • system controllers such as pumps and measurement devices, and components of the system designed to coordinate these functions.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Hematology (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Dispersion Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Apparatus Associated With Microorganisms And Enzymes (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Investigating Or Analysing Biological Materials (AREA)
US10/064,392 2002-04-26 2002-07-09 Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species Abandoned US20030203504A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US10/064,392 US20030203504A1 (en) 2002-04-26 2002-07-09 Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species
PCT/US2003/013181 WO2003091732A2 (fr) 2002-04-26 2003-04-25 Procede base sur la diffusion et systeme pour detecter et surveiller l'activite d'especes biologiques et chimiques
AU2003234271A AU2003234271A1 (en) 2002-04-26 2003-04-25 Diffusion-based method and system for detecting and monitoring activity of biologic and chemical species
US10/799,000 US7713477B2 (en) 2002-04-26 2004-03-11 Systems and methods for monitoring chemical and biological activities using differential measurements
US12/777,273 US20100296973A1 (en) 2002-04-26 2010-05-11 Systems and Methods for Monitoring Chemical and Biological Activity using Differential Measurements

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37566802P 2002-04-26 2002-04-26
US10/064,392 US20030203504A1 (en) 2002-04-26 2002-07-09 Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/799,000 Continuation-In-Part US7713477B2 (en) 2002-04-26 2004-03-11 Systems and methods for monitoring chemical and biological activities using differential measurements

Publications (1)

Publication Number Publication Date
US20030203504A1 true US20030203504A1 (en) 2003-10-30

Family

ID=29253871

Family Applications (3)

Application Number Title Priority Date Filing Date
US10/064,392 Abandoned US20030203504A1 (en) 2002-04-26 2002-07-09 Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species
US10/799,000 Expired - Fee Related US7713477B2 (en) 2002-04-26 2004-03-11 Systems and methods for monitoring chemical and biological activities using differential measurements
US12/777,273 Abandoned US20100296973A1 (en) 2002-04-26 2010-05-11 Systems and Methods for Monitoring Chemical and Biological Activity using Differential Measurements

Family Applications After (2)

Application Number Title Priority Date Filing Date
US10/799,000 Expired - Fee Related US7713477B2 (en) 2002-04-26 2004-03-11 Systems and methods for monitoring chemical and biological activities using differential measurements
US12/777,273 Abandoned US20100296973A1 (en) 2002-04-26 2010-05-11 Systems and Methods for Monitoring Chemical and Biological Activity using Differential Measurements

Country Status (3)

Country Link
US (3) US20030203504A1 (fr)
AU (1) AU2003234271A1 (fr)
WO (1) WO2003091732A2 (fr)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040115830A1 (en) * 2002-09-25 2004-06-17 Igor Touzov Components for nano-scale Reactor
US20060065532A1 (en) * 2004-09-30 2006-03-30 Matthias Stiene Microfluidic analytical system with accessible electrically conductive contact pads
US20060074143A1 (en) * 2004-09-30 2006-04-06 Rodgers James I Fusible conductive ink for use in manufacturing microfluidic analytical systems
US20070244258A1 (en) * 2006-03-29 2007-10-18 Shanti Swarup Clear coating compositions with improved scratch resistance
US20080257071A1 (en) * 2005-11-25 2008-10-23 Koninklijke Philips Electronics, N.V. Microfluidic Device with Porous Membrane and an Unbranched Channel
US8945914B1 (en) 2010-07-08 2015-02-03 Sandia Corporation Devices, systems, and methods for conducting sandwich assays using sedimentation
US8962346B2 (en) 2010-07-08 2015-02-24 Sandia Corporation Devices, systems, and methods for conducting assays with improved sensitivity using sedimentation
US8988881B2 (en) 2007-12-18 2015-03-24 Sandia Corporation Heat exchanger device and method for heat removal or transfer
US9005417B1 (en) 2008-10-01 2015-04-14 Sandia Corporation Devices, systems, and methods for microscale isoelectric fractionation
EP2764373A4 (fr) * 2011-10-04 2015-07-01 Aseptia Inc Mesure de conductivité de fluides
US20150184224A1 (en) * 2012-07-13 2015-07-02 Biomerieux Automated system for the lysis of microorganisms present in a sample, for extraction and for purification of the nucleic acids of said microorganisms for purposes of analysis
US9244065B1 (en) 2012-03-16 2016-01-26 Sandia Corporation Systems, devices, and methods for agglutination assays using sedimentation
US9261100B2 (en) 2010-08-13 2016-02-16 Sandia Corporation Axial flow heat exchanger devices and methods for heat transfer using axial flow devices
US9702871B1 (en) 2014-11-18 2017-07-11 National Technology & Engineering Solutions Of Sandia, Llc System and method for detecting components of a mixture including a valving scheme for competition assays
US9795961B1 (en) 2010-07-08 2017-10-24 National Technology & Engineering Solutions Of Sandia, Llc Devices, systems, and methods for detecting nucleic acids using sedimentation
US10254298B1 (en) 2015-03-25 2019-04-09 National Technology & Engineering Solutions Of Sandia, Llc Detection of metabolites for controlled substances
US10406528B1 (en) 2016-08-04 2019-09-10 National Technology & Engineering Solutions Of Sandia, Llc Non-contact temperature control system for microfluidic devices
WO2020009897A1 (fr) * 2018-07-06 2020-01-09 Qorvo Us, Inc. Canaux fluidiques comprenant un capteur de conductivité et leurs procédés d'utilisation
US10590477B2 (en) 2013-11-26 2020-03-17 National Technology & Engineering Solutions Of Sandia, Llc Method and apparatus for purifying nucleic acids and performing polymerase chain reaction assays using an immiscible fluid
US10786811B1 (en) 2016-10-24 2020-09-29 National Technology & Engineering Solutions Of Sandia, Llc Detection of active and latent infections with microfluidic devices and systems thereof
US10981174B1 (en) 2016-08-04 2021-04-20 National Technology & Engineering Solutions Of Sandia, Llc Protein and nucleic acid detection for microfluidic devices
US11674873B2 (en) * 2015-07-08 2023-06-13 Wyatt Technology Corporation Differential viscometer with solvent compressibility correction

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE49221E1 (en) 2002-06-14 2022-09-27 Parker Intangibles, Llc Single-use manifolds for automated, aseptic handling of solutions in bioprocessing applications
US7857506B2 (en) * 2005-12-05 2010-12-28 Sencal Llc Disposable, pre-calibrated, pre-validated sensors for use in bio-processing applications
US7922976B2 (en) * 2006-10-23 2011-04-12 Banpil Photonics, Inc. High sensitivity sensor device and manufacturing thereof
FR2942041B1 (fr) * 2009-02-06 2011-02-25 Commissariat Energie Atomique Dispositif embarque d'analyse d'un fluide corporel.
CN102645673B (zh) * 2011-02-22 2017-05-31 洛克威尔自动控制技术股份有限公司 感应邻近传感器
CA2833897C (fr) 2011-05-09 2020-05-19 Advanced Liquid Logic, Inc. Retroaction microfluidique utilisant une detection d'impedance
GB201216163D0 (en) * 2012-09-11 2012-10-24 Exacsys Ltd Devices and methods for measurement of sample properties
US9476824B2 (en) * 2012-10-12 2016-10-25 Purdue Research Foundation Optical chemical classification
US20140368443A1 (en) * 2013-06-14 2014-12-18 Agilent Technologies, Inc. System for Automating Laboratory Experiments
US10196678B2 (en) 2014-10-06 2019-02-05 ALVEO Technologies Inc. System and method for detection of nucleic acids
US9921182B2 (en) 2014-10-06 2018-03-20 ALVEO Technologies Inc. System and method for detection of mercury
US9506908B2 (en) * 2014-10-06 2016-11-29 Alveo Technologies, Inc. System for detection of analytes
US10627358B2 (en) 2014-10-06 2020-04-21 Alveo Technologies, Inc. Method for detection of analytes
US10352899B2 (en) 2014-10-06 2019-07-16 ALVEO Technologies Inc. System and method for detection of silver
US20230183779A1 (en) * 2014-11-07 2023-06-15 Alveo Technologies, Inc. System and method for detection of nucleic acids
CA3037494A1 (fr) 2016-09-23 2018-03-29 Alveo Technologies, Inc. Methodes et compositions de detection d'analytes
US10502707B1 (en) * 2018-05-31 2019-12-10 Taiwan Semiconductor Manufacturing Co., Ltd. Differential sensing with bioFET sensors

Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3941563A (en) * 1974-04-23 1976-03-02 E. I. Du Pont De Nemours & Company Method and apparatus for detecting hexavalent chromium
US3999047A (en) * 1972-09-05 1976-12-21 Green James E Method and apparatus utilizing color algebra for analyzing scene regions
US5192507A (en) * 1987-06-05 1993-03-09 Arthur D. Little, Inc. Receptor-based biosensors
US5212988A (en) * 1988-02-29 1993-05-25 The Reagents Of The University Of California Plate-mode ultrasonic structure including a gel
US5267985A (en) * 1993-02-11 1993-12-07 Trancell, Inc. Drug delivery by multiple frequency phonophoresis
US5554339A (en) * 1988-11-14 1996-09-10 I-Stat Corporation Process for the manufacture of wholly microfabricated biosensors
US5716852A (en) * 1996-03-29 1998-02-10 University Of Washington Microfabricated diffusion-based chemical sensor
US5837115A (en) * 1993-06-08 1998-11-17 British Technology Group Usa Inc. Microlithographic array for macromolecule and cell fractionation
US5837200A (en) * 1995-06-02 1998-11-17 Bayer Aktiengesellschaft Sorting device for biological cells or viruses
US5907016A (en) * 1993-03-29 1999-05-25 Virginia Tech Intellectual Properties,Inc. Method of coupling ligands onto supports and products produced therefrom
US5910286A (en) * 1995-02-21 1999-06-08 Thomson-Csf Highly selective chemical sensor
US5932100A (en) * 1995-06-16 1999-08-03 University Of Washington Microfabricated differential extraction device and method
US5948684A (en) * 1997-03-31 1999-09-07 University Of Washington Simultaneous analyte determination and reference balancing in reference T-sensor devices
US5952173A (en) * 1994-09-30 1999-09-14 Abbott Laboratories Devices and methods utilizing arrays of structures for analyte capture
US5955028A (en) * 1996-08-02 1999-09-21 Caliper Technologies Corp. Analytical system and method
US5965410A (en) * 1997-09-02 1999-10-12 Caliper Technologies Corp. Electrical current for controlling fluid parameters in microchannels
US5971158A (en) * 1996-06-14 1999-10-26 University Of Washington Absorption-enhanced differential extraction device
US6007775A (en) * 1997-09-26 1999-12-28 University Of Washington Multiple analyte diffusion based chemical sensor
US6143574A (en) * 1995-11-14 2000-11-07 Biacore Ab Method of determining affinity or kinetic properties in solution
US6241950B1 (en) * 1998-02-13 2001-06-05 Airxpert Systems, Inc. Fluid sampling system
US6274089B1 (en) * 1998-06-08 2001-08-14 Caliper Technologies Corp. Microfluidic devices, systems and methods for performing integrated reactions and separations
US6275089B1 (en) * 2000-01-13 2001-08-14 Chartered Semiconductor Manufacturing Ltd. Low voltage controllable transient trigger network for ESD protection

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3592043A (en) 1969-01-27 1971-07-13 Varian Associates Micro-adsorption detector and method of using same
SE407115B (sv) * 1975-10-06 1979-03-12 Kabi Ab Forfarande och metelektroder for studium av enzymatiska och andra biokemiska reaktioner
JPS5646450A (en) 1979-09-21 1981-04-27 Terumo Corp Detector for hematic emulsion in blood specimen
US4690152A (en) 1985-10-23 1987-09-01 American Mediscan, Inc. Apparatus for epithelial tissue impedance measurements
US5004583A (en) * 1987-01-29 1991-04-02 Medtest Systems, Inc. Universal sensor cartridge for use with a universal analyzer for sensing components in a multicomponent fluid
US5597534A (en) * 1994-07-05 1997-01-28 Texas Instruments Deutschland Gmbh Apparatus for wireless chemical sensing
US20020090644A1 (en) * 1999-05-21 2002-07-11 Weigl Bernhard H. Microscale diffusion immunoassay
GB9822242D0 (en) * 1998-10-13 1998-12-09 Zeneca Ltd Device
US6455000B1 (en) 1999-07-12 2002-09-24 Fantom Technologies Inc. Method and apparatus for measuring the concentration of a gas
US6534012B1 (en) 2000-08-02 2003-03-18 Sensys Medical, Inc. Apparatus and method for reproducibly modifying localized absorption and scattering coefficients at a tissue measurement site during optical sampling
JP2004509335A (ja) * 2000-09-18 2004-03-25 ユニバーシティ　オブ　ワシントン 複数のフローストリーム間の流体界面の回転操作のための微小流体デバイス
US6818109B2 (en) 2000-09-29 2004-11-16 Kabushiki Kaisha Toshiba Nucleic acid detections sensor
US6825655B2 (en) 2001-08-31 2004-11-30 Imego Ab Method and arrangement for detecting changes of a magnetic response in magnetic particles

Patent Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3999047A (en) * 1972-09-05 1976-12-21 Green James E Method and apparatus utilizing color algebra for analyzing scene regions
US3941563A (en) * 1974-04-23 1976-03-02 E. I. Du Pont De Nemours & Company Method and apparatus for detecting hexavalent chromium
US5192507A (en) * 1987-06-05 1993-03-09 Arthur D. Little, Inc. Receptor-based biosensors
US5212988A (en) * 1988-02-29 1993-05-25 The Reagents Of The University Of California Plate-mode ultrasonic structure including a gel
US5554339A (en) * 1988-11-14 1996-09-10 I-Stat Corporation Process for the manufacture of wholly microfabricated biosensors
US5267985A (en) * 1993-02-11 1993-12-07 Trancell, Inc. Drug delivery by multiple frequency phonophoresis
US5907016A (en) * 1993-03-29 1999-05-25 Virginia Tech Intellectual Properties,Inc. Method of coupling ligands onto supports and products produced therefrom
US5837115A (en) * 1993-06-08 1998-11-17 British Technology Group Usa Inc. Microlithographic array for macromolecule and cell fractionation
US5952173A (en) * 1994-09-30 1999-09-14 Abbott Laboratories Devices and methods utilizing arrays of structures for analyte capture
US5910286A (en) * 1995-02-21 1999-06-08 Thomson-Csf Highly selective chemical sensor
US5837200A (en) * 1995-06-02 1998-11-17 Bayer Aktiengesellschaft Sorting device for biological cells or viruses
US5932100A (en) * 1995-06-16 1999-08-03 University Of Washington Microfabricated differential extraction device and method
US6143574A (en) * 1995-11-14 2000-11-07 Biacore Ab Method of determining affinity or kinetic properties in solution
US5716852A (en) * 1996-03-29 1998-02-10 University Of Washington Microfabricated diffusion-based chemical sensor
US6171865B1 (en) * 1996-03-29 2001-01-09 University Of Washington Simultaneous analyte determination and reference balancing in reference T-sensor devices
US5972710A (en) * 1996-03-29 1999-10-26 University Of Washington Microfabricated diffusion-based chemical sensor
US5971158A (en) * 1996-06-14 1999-10-26 University Of Washington Absorption-enhanced differential extraction device
US5955028A (en) * 1996-08-02 1999-09-21 Caliper Technologies Corp. Analytical system and method
US5948684A (en) * 1997-03-31 1999-09-07 University Of Washington Simultaneous analyte determination and reference balancing in reference T-sensor devices
US5965410A (en) * 1997-09-02 1999-10-12 Caliper Technologies Corp. Electrical current for controlling fluid parameters in microchannels
US6007775A (en) * 1997-09-26 1999-12-28 University Of Washington Multiple analyte diffusion based chemical sensor
US6241950B1 (en) * 1998-02-13 2001-06-05 Airxpert Systems, Inc. Fluid sampling system
US6274089B1 (en) * 1998-06-08 2001-08-14 Caliper Technologies Corp. Microfluidic devices, systems and methods for performing integrated reactions and separations
US6275089B1 (en) * 2000-01-13 2001-08-14 Chartered Semiconductor Manufacturing Ltd. Low voltage controllable transient trigger network for ESD protection

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040115830A1 (en) * 2002-09-25 2004-06-17 Igor Touzov Components for nano-scale Reactor
US20060065532A1 (en) * 2004-09-30 2006-03-30 Matthias Stiene Microfluidic analytical system with accessible electrically conductive contact pads
US20060074143A1 (en) * 2004-09-30 2006-04-06 Rodgers James I Fusible conductive ink for use in manufacturing microfluidic analytical systems
US7402616B2 (en) 2004-09-30 2008-07-22 Lifescan, Inc. Fusible conductive ink for use in manufacturing microfluidic analytical systems
US20080257071A1 (en) * 2005-11-25 2008-10-23 Koninklijke Philips Electronics, N.V. Microfluidic Device with Porous Membrane and an Unbranched Channel
US20070244258A1 (en) * 2006-03-29 2007-10-18 Shanti Swarup Clear coating compositions with improved scratch resistance
US8988881B2 (en) 2007-12-18 2015-03-24 Sandia Corporation Heat exchanger device and method for heat removal or transfer
US9005417B1 (en) 2008-10-01 2015-04-14 Sandia Corporation Devices, systems, and methods for microscale isoelectric fractionation
US8962346B2 (en) 2010-07-08 2015-02-24 Sandia Corporation Devices, systems, and methods for conducting assays with improved sensitivity using sedimentation
US10384202B2 (en) 2010-07-08 2019-08-20 National Technology & Engineering Solutions Of Sandia, Llc Devices, systems, and methods for detecting nucleic acids using sedimentation
US9795961B1 (en) 2010-07-08 2017-10-24 National Technology & Engineering Solutions Of Sandia, Llc Devices, systems, and methods for detecting nucleic acids using sedimentation
US8945914B1 (en) 2010-07-08 2015-02-03 Sandia Corporation Devices, systems, and methods for conducting sandwich assays using sedimentation
US9261100B2 (en) 2010-08-13 2016-02-16 Sandia Corporation Axial flow heat exchanger devices and methods for heat transfer using axial flow devices
US9404952B2 (en) 2011-10-04 2016-08-02 Aseptia, Inc. Conductivity measurement of fluids
EP2764373A4 (fr) * 2011-10-04 2015-07-01 Aseptia Inc Mesure de conductivité de fluides
US9244065B1 (en) 2012-03-16 2016-01-26 Sandia Corporation Systems, devices, and methods for agglutination assays using sedimentation
US10619185B2 (en) * 2012-07-13 2020-04-14 Biomerieux Automated system for the lysis of microorganisms present in a sample, for extraction and for purification of the nucleic acids of said microorganisms for purposes of analysis
US20150184224A1 (en) * 2012-07-13 2015-07-02 Biomerieux Automated system for the lysis of microorganisms present in a sample, for extraction and for purification of the nucleic acids of said microorganisms for purposes of analysis
US11427854B2 (en) 2012-07-13 2022-08-30 Biomerieux Automated system for the lysis of microorganisms present in a sample, for extraction and for purification of the nucleic acids of said microorganisms for purposes of analysis
US10590477B2 (en) 2013-11-26 2020-03-17 National Technology & Engineering Solutions Of Sandia, Llc Method and apparatus for purifying nucleic acids and performing polymerase chain reaction assays using an immiscible fluid
US9766230B1 (en) 2014-11-18 2017-09-19 National Technology & Engineering Solutions Of Sandia, Llc System and method for detecting components of a mixture including a valving scheme for competition assays
US9702871B1 (en) 2014-11-18 2017-07-11 National Technology & Engineering Solutions Of Sandia, Llc System and method for detecting components of a mixture including a valving scheme for competition assays
US10254298B1 (en) 2015-03-25 2019-04-09 National Technology & Engineering Solutions Of Sandia, Llc Detection of metabolites for controlled substances
US10969398B2 (en) 2015-03-25 2021-04-06 National Technology & Engineering Solutions Of Sandia, Llc Detection of metabolites for controlled substances
US11674873B2 (en) * 2015-07-08 2023-06-13 Wyatt Technology Corporation Differential viscometer with solvent compressibility correction
US10406528B1 (en) 2016-08-04 2019-09-10 National Technology & Engineering Solutions Of Sandia, Llc Non-contact temperature control system for microfluidic devices
US10981174B1 (en) 2016-08-04 2021-04-20 National Technology & Engineering Solutions Of Sandia, Llc Protein and nucleic acid detection for microfluidic devices
US10786811B1 (en) 2016-10-24 2020-09-29 National Technology & Engineering Solutions Of Sandia, Llc Detection of active and latent infections with microfluidic devices and systems thereof
WO2020009897A1 (fr) * 2018-07-06 2020-01-09 Qorvo Us, Inc. Canaux fluidiques comprenant un capteur de conductivité et leurs procédés d'utilisation

Also Published As

Publication number Publication date
WO2003091732A2 (fr) 2003-11-06
US7713477B2 (en) 2010-05-11
WO2003091732A3 (fr) 2004-03-25
US20100296973A1 (en) 2010-11-25
AU2003234271A1 (en) 2003-11-10
US20040170530A1 (en) 2004-09-02

Similar Documents

Publication Publication Date Title
US20030203504A1 (en) Diffusion-based system and method for detecting and monitoring activity of biologic and chemical species
Adamo et al. Microfluidics-based assessment of cell deformability
Han et al. Microfluidic lysis of human blood for leukocyte analysis using single cell impedance cytometry
US6007775A (en) Multiple analyte diffusion based chemical sensor
US9110010B2 (en) Electrical detection using confined fluids
US20030032000A1 (en) Method for analyzing cellular events
US7968305B2 (en) Biochips including ion transport detecting structures and methods of use
Gifford et al. Parallel microchannel-based measurements of individual erythrocyte areas and volumes
US20190187148A1 (en) Biomolecular interaction detection devices and methods
US20070231783A1 (en) Synthetic microfluidic microvasculature network
Gu et al. Cellular electrical impedance spectroscopy: an emerging technology of microscale biosensors
EP3495811A1 (fr) Onde acoustique de surface de recirculation portable et son procédé de fonctionnement
CN108593910A (zh) 基于微球载体的粒子检测系统及方法
CN108700499A (zh) 流体中悬浮粒子的无标记表征
Selmi et al. Numerical study of the electrothermal effect on the kinetic reaction of immunoassays for a microfluidic biosensor
Khajvand et al. Interfacing droplet microfluidics with antibody barcodes for multiplexed single-cell protein secretion profiling
Špačková et al. Nanoplasmonic–nanofluidic single-molecule biosensors for ultrasmall sample volumes
CN208140539U (zh) 基于微球载体的粒子检测系统
Huang et al. Concurrent detection of cellular and molecular cancer markers using an immunomagnetic flow system
Huang et al. Multiplexed spectral signature detection for microfluidic color-coded bioparticle flow
Chapman et al. Label-free resistive-pulse cytometry
EP2751556B1 (fr) Dispositif et procédé de détection et de quantification de protéines immunologiques, agents et cellules pathogènes et microbiens
Moore et al. Single cell functional analysis of multiple myeloma cell populations correlates with diffusion profiles in static microfluidic coculture systems
Jacquat et al. Single-Molecule Sizing through Nanocavity Confinement
CN207991930U (zh) 微纳粒子检测系统

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION