WO2007143541A2 - DÉtecteur thermique pour agents chimiques ou biologiques - Google Patents

DÉtecteur thermique pour agents chimiques ou biologiques Download PDF

Info

Publication number
WO2007143541A2
WO2007143541A2 PCT/US2007/070208 US2007070208W WO2007143541A2 WO 2007143541 A2 WO2007143541 A2 WO 2007143541A2 US 2007070208 W US2007070208 W US 2007070208W WO 2007143541 A2 WO2007143541 A2 WO 2007143541A2
Authority
WO
WIPO (PCT)
Prior art keywords
airborne
interest
reactive
detector
agent
Prior art date
Application number
PCT/US2007/070208
Other languages
English (en)
Other versions
WO2007143541A3 (fr
Inventor
David J. Lawrence
W. Gene Tucker
Thomas C. Devore
George L. Coffman
Ronald W. Raab
Gerald R. Taylor
Original Assignee
James Madison University
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 James Madison University filed Critical James Madison University
Publication of WO2007143541A2 publication Critical patent/WO2007143541A2/fr
Publication of WO2007143541A3 publication Critical patent/WO2007143541A3/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
    • G01N25/4806—Details not adapted to a particular type of sample
    • G01N25/4813—Details not adapted to a particular type of sample concerning the measuring means
    • G01N25/482—Details not adapted to a particular type of sample concerning the measuring means concerning the temperature responsive elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
    • G01N25/4873—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation for a flowing, e.g. gas sample

Definitions

  • the present application relates to detecting chemical or biological agents of interest, for example chemical or biological agents in the air or in liquids.
  • a detector comprises a thermoelectric sensor and a reactive layer.
  • the thermoelectric sensor is configured to sense heat and to provide an electrical signal based on the sensed heat.
  • the reactive layer is coupled to the thermoelectric sensor and is reactive with an airborne chemical or airborne biological agent of interest.
  • the reaction is exothermic or endothermic.
  • the airborne agent of interest reacts with the coating, the reaction is detected by the thermoelectric sensor which produces an electrical signal.
  • the electrical signal provides an indication of the reaction.
  • a method comprises sensing heat on a material having an exothermic or endothermic reaction with an airborne chemical or airborne biological agent of interest. The method further comprises converting the sensed heat to an electrical signal indicative of the amount of heat sensed.
  • thermoelectric alarm system comprises a plurality of detectors as described above.
  • Each of the detectors comprises a reactive layer reactive with the same or different airborne chemical or airborne biological agent of interest.
  • a control system is configured to receive the electrical signals, to determine when an alarm condition exists, and to provide an alarm output signal based on the determination.
  • FIGs. 1A-1B are top and cross-sectional views, respectively, of a thermoelectric sensor, according to an exemplary embodiment
  • FIGs. 2A-2B are top and bottom views, respectively, of a thermoelectric sensor, according to an alternative embodiment
  • FIG. 3 is a cross-sectional view of a thermoelectric sensor, according to another alternative embodiment
  • FIG. 4 is a schematic diagram of a thermoelectric sensor, according to another exemplary embodiment
  • FIG. 5 is a top view of an array of thermoelectric sensors, one of which has a reactive layer, according to an exemplary embodiment
  • FIG. 6 is a graph of sensor output voltage from a thermoelectric sensor illustrating a hexane droplet test, according to an exemplary embodiment
  • FIG. 7 is a perspective view of a flow tube apparatus used in some experiments, according to an exemplary embodiment
  • FIG. 8 is a graph of sensor output voltage in response to injection of approximately
  • FIG. 9 is a graph of integrated sensor output as a function of energy required to vaporize hexane droplets applied to a thermoelectric sensor, according to an exemplary embodiment
  • FIG. 10 is a graph of sensor output over time of a copper oxalate-coated sensor to short-term exposures of approximately 0.9 and approximately 20 ppm of ammonia vapor, according to an exemplary embodiment
  • FIG. 11 is a graph of integrated sensor output as a function of the logarithm of the ammonia concentration, according to an exemplary embodiment
  • FIG. 12 is a graph of changes in the infrared spectrum observed when ammonia reacts with copper oxalate, according to an exemplary embodiment
  • FIG. 13 is a graph of sensor output voltage in response to injection of approximately 70 ppm ammonia into the flow tube test apparatus of FIG. 7, according to an exemplary embodiment
  • FIG. 14 is a schematic diagram of a detector for biological agents of interest, according to an exemplary embodiment
  • FIG. 15 is a schematic diagram of a detector for the anthrax spore protein BcIA, according to an exemplary embodiment
  • FIG. 16 is a schematic diagram of a detection and alarm system, according to an exemplary embodiment.
  • FIG. 17 is a flowchart illustrating a method of detecting an airborne chemical or biological agent of interest, according to an exemplary embodiment.
  • Described herein is a system and method for detecting airborne or liquid chemical or biological agents of interest or substances of concern. Also described is a system and method for detecting airborne or liquid chemical or biological agents of interest which is inexpensive to mass produce. Also described is a system that will detect several types of chemical and biological agents. Further described is a system and method to alert persons or operating systems of the presence of an agent of interest to, for example, allow them to initiate emergency procedures such as changing operation of the building ventilation system or advising occupants to take protective action (e.g., to don masks, go to a designated place in the building, exit the building, etc.). [0027] The teachings herein extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the above- mentioned objectives.
  • a detector comprising (i) a thermoelectric sensor configured to sense heat and to provide an electrical signal based on the sensed heat and (ii) a reactive layer coupled to the thermoelectric sensor which is reactive with an airborne chemical or airborne biological agent of interest, the reaction being exothermic or endothermic.
  • a thermoelectric sensor configured to sense heat and to provide an electrical signal based on the sensed heat
  • a reactive layer coupled to the thermoelectric sensor which is reactive with an airborne chemical or airborne biological agent of interest, the reaction being exothermic or endothermic.
  • the thermoelectric sensor may be any thermoelectric sensor that can be configured to sense heat and to provide an electrical signal based on the sensed heat.
  • the reactive layer may be any reactive layer that is reactive in an exothermic or endothermic reaction with an airborne chemical or airborne biological agent of interest.
  • the airborne chemical or airborne biological agent of interest may be any such agent of interest, including but not limited to agents that pose a threat to animal, human or public health or safety. Methods using such detectors to detect agents of interest also are provided.
  • a method comprising sensing heat on a material having an exothermic or endothermic reaction with an airborne chemical or airborne biological agent of interest. In some embodiments, the method further comprises converting the sensed heat to an electrical signal indicative of the amount of heat sensed.
  • thermoelectric alarm system comprising a plurality of detectors as described above.
  • Each of the detectors comprises a reactive layer reactive with the same or different airborne chemical or airborne biological agent of interest.
  • the system may further comprise a control system configured to receive the electrical signals, to determine when an alarm condition exists (e.g., when at least a threshold amount of an agent of interest is detected), and/or to provide an alarm output signal based on the determination.
  • Suitable control systems for carrying out one or more of these functions in response to an electrical signal are known and can be designed and implemented by the skilled practitioner.
  • Detector 10 comprises a thermoelectric sensor 12 configured to sense heat and to provide an electrical signal based on the sensed heat.
  • Sensor 12 may serve as a platform to detect temperature or heat differences.
  • Sensor 12 may comprise a thermocouple 13 and may further comprise a thermopile.
  • a thermopile comprises a plurality of series-connected thermocouples and provides a larger output voltage, and therefore a higher sensitivity, than a single thermocouple junction.
  • Sensor 12 may alternatively comprise other thermoelectric sensing components, such as bolometers, calorimeters, etc.
  • Sensor 12 may have a sensitivity, and may have a sensitivity greater than about 4 V-s/J (Volt-seconds per Joule), or between about 1 V-s/J and 100 V-s/J. Sensor 12 may have a sensitivity to detect temperature changes at low temperatures, such as at or below about 1x10 5 degrees Celsius. Sensor 12 may be configured with sufficient sensitivity to distinguish air temperature changes from temperature changes created by substance reactions with a reactive layer, as will be described below. The sensitivity of sensor 12 may be increased, for example, by increasing the number of thermopile junctions to increase the output voltage.
  • the sensitivity may be increased by increasing the thermal isolation between the sensing junctions and the reference junctions, for example, by thinning a membrane between a center and a perimeter of the device (e.g., via plasma etching).
  • Thermal modeling may be used to determine the benefits of changes in geometry of materials of the sensor design, or of the geometry of the coatings, for detecting both gaseous and particulate substances, and suitable geometries may be selected for optimal detection of the agents of interest.
  • Sensor 12 comprises one or more sensing junctions 14 and one or more (typically an equal number of) reference junctions 16.
  • thirty-six sensing junctions 14 are disposed in a cluster near a center 18 of sensor 12 and thirty- six reference junctions 16 are disposed on or near an outer perimeter 20 of sensor 12.
  • any number of thermocouples may be used, such as twenty- four, or preferably between about 1 and about 200 thermocouples, each having a sensing junction and a reference junction.
  • each thermocouple comprises an antimony conductor coupled to a bismuth conductor, though other conductive or semiconductive materials may be used, such as, nickel, chromium, aluminum, alloys, or doped silicon.
  • Sensor 12 may comprise a membrane 22 (e.g., polyimide, polyethylene terephthalate, or other material, which may be a "drumhead” membrane) supported by a plate 24 (e.g., aluminum, a semiconductor, or other material), the membrane 22 supporting a plurality of thermocouples comprising reference junctions thermally grounded to plate 24.
  • a membrane 22 e.g., polyimide, polyethylene terephthalate, or other material, which may be a "drumhead” membrane
  • a plate 24 e.g., aluminum, a semiconductor, or other material
  • Membrane 22 is shown in white in FIG. IA.
  • a first conductive material 25 is shown in light gray and includes signal output terminals 26, 28 and 30.
  • Terminal 30 is configured to provide a signal representing heat sensed on half of sensor 12, the half selected based on which of terminals 26 and 28 are used as the reference to terminal 30.
  • a second conductive material 32 is shown in black and comprises a material having a different voltage response to heat than first conductive material 25 to create the thermoelectric effect.
  • Plate 24 is shown in dark gray and supports or is coupled to membrane 22. Plate 24 also may comprise a thermally conductive material, such as a metal, to maintain a thermal ground for reference junctions 16.
  • Sensor 12 may be a variety of shapes and sizes, including square, rectangle, circle, oval, and other shapes. Junctions 14 and 16 may be laid out in a variety of configurations. In the illustrated embodiment, thermocouples 13 are in a "+" or “T” configuration, with reference junctions 16 arranged linearly and sensing junctions 14 arranged in a "V" shape, with each "V" shape from four different sets of thermocouples meeting at center 18. Outer perimeter 20 may have an outside edge 34 sized 9 mm by 9 mm, though other sizes are contemplated, such as between about 0.1 mm by 0.1 mm and 20 mm by 20 mm. [0038] Sensor 12 may be fabricated using any suitable techniques.
  • sensor 12 may be micro fabricated using techniques for depositing and patterning materials 25 and 32 on membrane 22 and/or plate 24.
  • the techniques may comprise one or more of thin film deposition, photolithography, etc., to form the thermocouple junctions between materials 25 and 32.
  • Thermocouples 13 may be protected with a protective layer 23, such as a spin- coated polystyrene film, silicon dioxide, or other material, disposed or between a reactive layer 50 and thermocouples 13, or coating thermocouples 13.
  • Layer 50 may be applied to protective layer 23.
  • Layer 50 may be applied to thermocouples 13 either with or without an intervening protective layer 23.
  • sensor 12 may be fabricated on plate 24 having an aperture 38 smaller than perimeter 20, wherein sensing junctions 14 are disposed on membrane 22 (over aperture 38) and reference junctions 16 are disposed over plate 24.
  • reference junctions 16 are "thermally grounded” in the sense that they are less responsive to rapid changes in ambient temperature.
  • Aperture 38 and membrane 22 define a drumhead area 51.
  • FIG. 2A and 2B an alternative embodiment of the detector is illustrated as detector 10'.
  • sensing and reference junctions 14', 16' are both disposed on membrane 22' so that the sensing and reference junctions will respond similarly to changes in ambient temperature.
  • Micrographs of sensor 12' are shown in FIGs. 2 A (top view) and 2B (bottom view).
  • the plate comprises a semiconductive material, such as silicon, and the thermocouples may be fabricated thereon using silicon (doped with boron) and aluminum as the conductive materials.
  • Sensor 100 comprises a semiconductive plate 102 of n-type material.
  • Sensor 100 comprises an etched well 104 which functions to increase the sensitivity of sensor 100 and speed up the response to detected temperature variations.
  • Thermocouples are fabricated on substrate 102 and comprise a first conductive material 106 (e.g., aluminum) and a second conductive material 108 (e.g., p-type silicon).
  • An insulative layer 110 such as silicon dioxide, is formed over a top surface 112 of plate 102, which insulates the major portions of corresponding first and second conductive materials in the plurality of thermocouples comprising the thermopile.
  • Sensor 100 may measure about 10 mm by 10 mm in the illustrated embodiment, though other sizes are contemplated.
  • thermoelectric sensor 12 is shown according to another exemplary embodiment.
  • sensor 12 comprises twenty- four sensing junctions 14" and twenty- four reference junctions 16" around a perimeter 20".
  • Each of thermocouples 13" comprises two materials, each material having a line width of approximately 80 micrometers.
  • Perimeter 20" measures approximately 10 mm by 10 mm. Every other strip 25 ' ' comprises a first conductive or semiconductive material and alternative strips 32" comprise a second conductive or semiconductive material.
  • detector 10 is shown comprising thermoelectric sensor 12 (which may be any of the alternative sensor embodiments referenced above or other sensor embodiments) and a reactive layer 50 coupled to sensor 12.
  • Reactive layer 50 is also shown in FIG. IB.
  • layer 50 is directly over the sensing junctions in order to enhance heat transfer from layer 50 to the sensing junctions.
  • Reactive layer 50 comprises a material (e.g., a chemical or biological material) which is reactive with an airborne chemical or airborne biological agent of interest, the reaction being exothermic or endothermic.
  • thermoelectric sensor 12 provides an electrical signal which may provide an indication based on the reaction.
  • a temperature change (e.g., heat released or absorbed) on layer 50 as a result of the reaction is detected by sensor 12.
  • the electrical signal output by sensor 12 may be a voltage, current or other signal, and may be indicative of a temperature, a change in temperature, a thermal event, or other indication indicating the presence or quantity of the agent of interest.
  • the electrical signal output by sensor 12 may be integrated.
  • the integrated output signal may be related to the concentration of the agent of interest, as will be described in exemplary form with reference to FIG. 11 below.
  • the relationship may alternatively be linear, curvilinear, such as logarithmic, or have some other relationship.
  • the agent of interest is not limited in any respect.
  • the agent of interest may be chemical, biological, or other, and may be a noxious pollutant, or other threat to animal , human or public health or safety.
  • the agent of interest may be in vapor or gas-phase, aerosol, liquid, or other form.
  • reactive layer 50 comprises a material (e.g., a chemical and/or biological material) which is reactive with an airborne chemical or airborne biological agent of interest, the reaction being exothermic or endothermic.
  • the material may be any chemical material (including mixtures of two or more materials) reactive in an exothermic or endothermic reaction with an airborne chemical or airborne biological agent of interest, and/or any biological material (including mixtures of two or more materials) reactive in an exothermic or endothermic reaction with an airborne chemical or airborne biological agent. Examples of materials and corresponding agents of interest are exemplified below.
  • Layer 50 may by applied as a coating to cover and make contact with at least a portion of thermoelectric sensor 12 and, more specifically, to make contact with sensing junctions 14 of sensor 12.
  • Layer 50 and sensor 12 may comprise an integrated device with layer 50 integral to sensor 12.
  • Layer 50 may be of any shape or size, and is shown in a circular shape in the illustrated embodiment, though square, oval, rectangular, oblong shapes, etc. are contemplated.
  • layer 50 is selective, i.e., it reacts with one or a limited number of chemical or biological agents of interest, or with one or a limited number of classes of chemical or biological agents of interest.
  • the reactive material will react with a sufficient selectivity to a baseline substance within the agent of interest, such that the reactive material will discriminate between normal indoor air substances and substances of concern.
  • the material reacts rapidly with the target agent at ambient temperatures to give a rapid response time, such as within a few seconds or a few minutes.
  • layer 50 is compatible with the materials used to fabricate sensor 12.
  • the material is a solid, or is applied as a solution or suspension that dries to solid or solid form.
  • the material adheres to the sensor and support (e.g., the polyimide membrane used to support the sensor).
  • Exemplary layers 50 and corresponding target agents of interest are illustrated in the table below.
  • agents of interest that may include cyanide, nerve agents such as sarin gas and mustard gases, and industrial chemicals, such as chlorine, sulfuric acid, nitrous acid, and other carcinogenic or organic chemicals, can be detected with appropriate combinations of metal complexes, metal hydroxides, and catalytic oxidation sensors.
  • Pathogenic bacteria, fungi (e.g., sporulating), and viruses that could be aerosolized within a building may also be detected.
  • the material is chosen to be reactive in an acid-base chemical reaction with the target agent .
  • the chemistry of acid-base reactions has been investigated in detail and is well-known and well-understood. Acid-base reactions occur rapidly at room temperature, particularly in solution, and often produce large heat changes. In addition, many solid acids and bases are known.
  • Gaseous acids like HCl or HCN and bases such as NH 3 are environmental hazards and there is considerable interest in sensors for these types of materials. B. Timmer, W.
  • An exemplary method for testing for chemical reactivity between a solid and vapor molecules comprises placing a plastic weighing boat containing a carefully weighed amount of the solid compound into a capped 2000 ml beaker containing vapor in equilibrium with a solution of the test molecule. Color change, mass change, and infrared (IR) spectroscopy may be used to determine if a reaction has occurred and to estimate the rate of reaction.
  • IR infrared
  • a prototype base may be ammonia and a prototype acid may be acetic acid.
  • Salts of nickel, copper, and zinc have been found to react with ammonia vapor and reactions between the oxalate salts of these metals and ammonia were selected for use because these salts are inexpensive, readily available, do not dissolve in water and adhere to the polyimide film.
  • the rate of heat released (q) during a chemical reaction can be calculated if the rate of reaction and the enthalpy change ( ⁇ H) are known:
  • the rate of reaction can be measured by determining the mass change that occurs when the coating compound (e.g., reactive material) is placed in the headspace of a covered
  • the enthalpy change can be determined using differential scanning calorimetry
  • DSC ammonia vapor reaction
  • Nickel, copper, and zinc oxalate reacted rapidly with ammonia. Since the copper compound does not have waters of hydration, it was anticipated that it would have the largest ⁇ H. New bands at -3300 cm “1 , -1400 cm “1 , and -950 cm “1 that can readily be assigned as the N-H stretch, the H-N-H bend and the umbrella modes of the complexed ammonia respectively were observed in the IR spectrum when copper oxalate was exposed to NH3 vapor. This confirmed that a rapid reaction had occurred. See FIG. 12, in which changes in the IR spectrum were observed when ammonia reacted with copper oxalate.
  • a flow tube apparatus 90 shown in FIG. 7 may be used for exposing the sensors to air streams containing various pulsed concentrations of, for example, ammonia. Air is drawn through an inlet 92 at a top portion 94, passes down a flow tube 96, and floods a surface 98 of the array, shown mounted (sensor leads are not shown in this figure). Air flow is drawn by a sampling pump through a bottom outlet 100. Injections of ammonia vapor into the inlet air stream create pulses of ammonia at known concentrations. As illustrated, the arrays have one sensor coated with a reactive material and two uncoated sensors. Air temperature variability is sensed by all three sensors; the ammonia pulse is detected by the difference in signals from the coated and uncoated sensors. A similar apparatus and procedure may be implemented for testing bioaerosols and other agents.
  • thermoelectric sensor suitable for detecting agents of interest.
  • the calculations below indicate that the energy flux to a sensor from an air concentration of 1000 ppm of a gaseous substance would be roughly 2 x 10 "4 J/s to 5 x 10 "4 J/s.
  • the mass flux to the sensor surface would be proportional to the mass diffusivity of the substance in air and the concentration difference between the air concentration in the room and the concentration at the surface of the coating.
  • the mass flux would be inversely proportional to the thickness of the "film” above the sensor surface (i.e., the distance over which the concentration gradient exists).
  • F D ⁇ C/ ⁇ x.
  • the coated area of the sensor is 10 mm x 10 mm, or 10 "4 m 2 , the mass rate to an individual sensor would be roughly 2 x 10 "9 mole/s.
  • Multiplying #6 times #7 gives an energy flow rate to a sensor of roughly 10 "2 J/s. [0065] A more typical heat of reaction would be about 50 kcal/mole (1000 kcal/mole assumption above was based on a typical heat of combustion). Using this value leads to an energy flow rate of roughly 5 x 10 "4 J/s.
  • M mass on sink surface, mg/m 2
  • n "a constant that accounts for nonlinearities in the desorption process”
  • k a adsorption rate coefficient, m/h
  • C g VOC concentration in air, mg/m .
  • the biological reactive agent is a member of a binding pair
  • the complementary member of the binding pair is associated with the agent of interest.
  • binding pair refers to two molecules which interact with each other through any of a variety of molecular forces including, for example, ionic, covalent, hydrophobic, van der Waals, and hydrogen bonding, so that the pair have the property of binding specifically to each other.
  • Specific binding means that the binding pair members exhibit binding to each other under conditions where they do not bind to another molecule.
  • binding pairs are biotin-avidin, hormone -receptor, receptor-ligand, enzyme- substrate, lgG-protein A, antigen-antibody, and the like.
  • layer 50 may comprise at least one biological reactive agent 60, such as an antibody (e.g., monoclonal, polyclonal, single chain, recombinant, etc.) or receptor or ligand protein reactive with a biological airborne agent of interest 62.
  • biological reactive agent 60 such as an antibody (e.g., monoclonal, polyclonal, single chain, recombinant, etc.) or receptor or ligand protein reactive with a biological airborne agent of interest 62.
  • an antibody e.g., monoclonal, polyclonal, single chain, recombinant, etc.
  • receptor or ligand protein reactive with a biological airborne agent of interest 62 e.g., antigens associated with a number of biological agents of interest are known, and methods of making antibodies for other antigens are well known. For example, antibodies against viruses, bacteria, pathogenic organisms, infectious agents, toxins and chemicals are known and others can be made using routine methods. Additionally or alternatively, the material may comprise a lig
  • layer 50 may comprise a protein, such as avidin, which can be used when the ligand biotin is used for system characterization. Biotin binding to the protein avidin produces moderate releases of heat energy. Swamy, M. J., "Thermodynamic analysis of biotin binding to avidin- a high-sensitivity titration calorimetric study," Biochemistery and Molecular Biology International 36(1), (1995), 219-225. Moy, V. T., EX. Florin, H.E. Gaub, "Intermolecular forces and energies between ligands and receptors," Science 266, (1994), 257-259.
  • avidin a protein, such as avidin
  • Bio agents which may be detected include and which are candidates for bioterrorism include bacterial pathogens, such as Yersinia pestis (plague), Burkholderia mallei (glanders), Burkholderia pseudomallei (melioidosis), Francisella tularensis (tularemia), and Bacillus anthracis (anthrax), and viruses, such as Smallpox, Ebola, and Marburg (hemorrhagic fever). See also Linda J. Utrup and Allan H.
  • detectors may have use in monitoring for 'sick building' conditions, for example, testing for the types of molds that grow on walls, under carpets, etc., i.e., molds that produce airborne spores which lead to allergic reactions in some people.
  • the biological reactive agent 60 (e.g., antibody, receptor protein, etc.) is disposed on membrane 22.
  • Biological reactive agent 60 may comprise an Fc fragment coupled to a surface 61 of membrane 22 and a Fab fragment coupled to the Fc fragment and configured to bind the antigen associated with the agent of interest. Additionally or alternatively, biological reactive agent 60 may comprise a protein (e.g., one produced by recombinant biotechnology) configured to bind to its partner ("binding protein") or ligand, respectively.
  • Conductor/sensing junction layer 64 represents various thermoelectric sensor elements described in greater detail with reference to FIGs. 1-4 above. In the illustrated embodiment, layer 50 is configured to detect bio-aerosols comprising antigen associated with an agent of interest. The antibodies disposed on the detector surface are chosen to specifically recognize and bind the antigen.
  • layer 50 comprises an anti-BclA antibody.
  • BcIA is an antigen associated with anthrax spores.
  • Conductor/sensing junction layer 64 represents various thermoelectric sensor elements described in greater detail with reference to FIGs. 1- 4 above.
  • the BcIA antigen in the form of a 'mock' spore
  • the antibody recognizes and binds the antigen in an exothermic reaction.
  • this detector may be used to detect bioaerosols, such as anthrax spores.
  • the 'mock' spore refers to the microsphere system described in the paragraph below, except that the protein
  • BcIA would be bound to the microsphere (instead of biotin).
  • Model systems to demonstrate the detection of biological agents of interest were designed.
  • One system uses commercially available microspheres to which are bound molecules of biotin. Such microspheres can be exposed to an airflow within a chamber containing a thermopile detector to which the protein avidin is bound, as described above.
  • Biotin/avidin binding may be determined by detection of transient temperature increases.
  • Another system uses actual bacterial spores, obtained from non-pathogenic bacteria genetically similar to Bacillus anthracis (anthrax), which may be generated by readily available sporulation culture materials and techniques. These spores, and/or purified outer spore surfaces, may be used to raise antibodies that specifically recognize and bind to the spores. These antibodies may be disposed on a sensor, such as via binding to polyimide membrane to which a thermopile is mounted, as described above. Spores, dried and/or aerosolized, can be introduced into an airflow and spore-antibody binding can be detected by transient temperature increases detected by the thermopile.
  • the polyimide (PI) membrane material (25 ⁇ m thick) was applied to the top surface of the aluminum plate and attached with a silicone adhesive.
  • a polyethylene terephthalate (PET) membrane material can be used, and an epoxy adhesive can be used rather than silicone adhesive.
  • photoresist was coated on the polyimide and it was photolithographically patterned in preparation for standard "liftoff processing. This left photoresist on all areas of the polyimide surface where no bismuth was wanted, with open windows in the photoresist where the bismuth was wanted, e.g., where the bismuth metal stripes were to be formed.
  • Bismuth was deposited on the patterned side of the sample by thermal evaporation.
  • the bismuth thickness was approximately 350 nm.
  • Photoresist was again coated on the sample surface and it was again photolithographically patterned in preparation for standard "liftoff processing. This time photoresist was left on all areas of the surface where no antimony was wanted, with open windows in the photoresist where the antimony was wanted, e.g., where the antimony metal stripes were to be formed.
  • Antimony was deposited on the patterned side of the sample by thermal evaporation.
  • the antimony thickness was approximately 350 nm.
  • the sample was placed in acetone baths which were gently agitated with ultrasonic energy in order to dissolve the photoresist, in the process lifting off all the unwanted antimony. Antimony was left behind only in the desired areas, specifically where there were open windows in the photoresist pattern.
  • the patterns are designed so that the antimony is deposited on top of bismuth in all locations where sensing and reference junctions are desired.
  • the bismuth and antimony stripe widths are approximately 60 ⁇ m.
  • Sensor 52 was coated with copper oxalate in a circular pattern having a diameter of approximately 2 mm to impart chemical sensitivity, in this case sensitivity to ammonia.
  • the flow tube test apparatus of FIG. 7 was used.
  • FIG. 8 illustrates a measurable, detectable increase in output voltage at point 58. The rise in the response begins about 6 seconds after introduction of the ammonia.
  • thermopile was fabricated having a sensitivity of > 4 V-s/J, as determined by solvent evaporation and acid-base reactions. This thermopile was fabricated using the same process described above in steps 1-12. In this case, in step 2 the square holes were 6.0mm x 6.0mm so that when completed, the reference junctions were disposed on the membrane material directly over aluminum, so that they are "thermally grounded". The device structure is shown in FIGS. IA and IB. In order to measure the sensitivity of the thermopiles, measured volumes of a solvent (e.g., hexane) were applied to the sensing junctions and the sensor output voltage was monitored as a function of time. Droplets ranging from 0.4 to 4 micro-liters were used.
  • a solvent e.g., hexane
  • Graphing the integrals of the voltage -time curves versus the energy required to vaporize the solvent gives the result shown in Fig. 9.
  • the slope for small solvent volumes yields a device sensitivity of > 4 V-s/J.
  • FIG. 11 also illustrates that sub-ppm concentrations of ammonia can be detected.
  • thermopile was fabricated having sensitivities ranging between 3 V/W and 6
  • thermopile was fabricated using the same process as described above with reference to steps 1-12. In this case, in step 2 the square holes were 6.0mm x 6.0mm so that when completed, the reference junctions were disposed on the membrane material directly over aluminum, so that they are "thermally grounded.” The device structure is shown in
  • FIGs. IA and IB are identical to FIGs. IA and IB.
  • FIG. 13 illustrates sensor output voltage for a thermoelectric sensor having a copper oxalate coating when exposed to ammonia vapor at about 70 parts per million.
  • Lewis acid-base approach can be used in accordance with the present description to detect gas-phase airborne contaminants. The results indicate that these reactions occur rapidly and that the enthalpy of reaction will limit the sensitivity. Increasing the enthalpy, and thus sensitivity, can be accomplished by a) changing the metal in the coating (e.g., zinc, nickel and cobalt oxalate), and b) modifying the ligand to produce more acidity at the metal, such as using acetate derivates such as trifluoroacetates.
  • the metal in the coating e.g., zinc, nickel and cobalt oxalate
  • modifying the ligand to produce more acidity at the metal, such as using acetate derivates such as trifluoroacetates.
  • a detection and alarm system 70 may comprise a plurality of detector modules 74 disposed throughout a building (e.g., in a ventilation duct, room, etc.). Each module 74 may comprise a plurality of detectors 10 that detect heat released or absorbed when airborne agents of interest react with specific surfaces. Each of detectors 10 may comprise a reactive layer reactive with the same or different airborne chemical or airborne biological agent of interest. Detectors 10 may comprise at least three detectors, or any number of detectors.
  • a control system 72 is coupled to detector modules 74 and is configured to receive the electrical signals, to determine when an alarm condition exists, and/or to provide an alarm output signal based on the determination.
  • control system 72 may be configured to provide the alarm output signal when the electrical signals indicate the presence of an agent of interest, an agent of interest in a concentration exceeding a predetermined level, or a sudden increase in concentration of the agent (e.g., in excess of a predetermine rate of increase).
  • the alarm may be audible, visual, an e-mail, a control signal to control a building system (such as a heating ventilation and air conditioning (HVAC) system, alarm system, evacuation alarm, etc), etc.
  • HVAC heating ventilation and air conditioning
  • detectors 10 may further be combined with and complement detectors using other sensing mechanisms (e.g., mass, resistance, or optical changes, etc.) in a single module 74 or multiple modules as part of detection and alarm system 70.
  • control system 72 may further comprise a data logger 76 and a computer 78, which may be separate components or combined into one computer (e.g., a server and client arrangement, a laptop, desktop, handheld computer, etc.).
  • Computer 78 may be configured to store sensor measurements from detectors 10.
  • Computer 78 may be configured to compare sensor measurements against a database of predetermined data for the agents of interest (e.g., thresholds) and optionally may provide or trigger the alarm output signal based on the comparison (e.g., sensor measurements exceeding a predetermined threshold, sensor measurements indicating a rapid rise in the concentration of the agent of interest, etc.).
  • computer 78 may further be configured to provide the alarm output signal based at least in part on a baseline level of the agent of interest (e.g., a baseline subtraction) to reduce or eliminate background noise in the data (e.g., trace amounts of the agents of interest, or noise within the system).
  • computer 78 may further be configured to provide a graphical user interface of current conditions throughout the building, such as, the current levels of agents of interest and whether computer 78 has identified any alert conditions.
  • computer 78 there may be a database within computer 78 and coupled to computer 78 that is configured to store the identity of typical air pollutants in buildings, their physical and chemical properties, and mathematical representations of "normal" variability in air concentrations.
  • computer 78 may be configured to compare sensor measurements to this database to prevent false positive alarms.
  • computer 78 may be configured to operate any software, code, or algorithms, such as neural networks, knowledge-based systems, etc.
  • thermoelectric sensor such as a thermocouple or thermopile.
  • the generated heat is converted to an electrical signal indicate of the amount of generated heat.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)

Abstract

L'invention concerne un détecteur comportant un capteur thermoélectrique et une couche réactive. Le capteur thermoélectrique est configuré pour détecter la chaleur et fournit un signal électrique basé sur la chaleur détectée. La couche réactive est couplée au capteur thermoélectrique et réagit avec un agent chimique ou biologique d'intérêt en suspension dans l'air. La réaction est exothermique ou endothermique. Quand l'agent d'intérêt en suspension dans l'air réagit avec le revêtement, la réaction est détectée par le capteur thermoélectrique. Le signal électrique fournit une indication sur la base de la réaction.
PCT/US2007/070208 2006-06-02 2007-06-01 DÉtecteur thermique pour agents chimiques ou biologiques WO2007143541A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US81068206P 2006-06-02 2006-06-02
US60/810,682 2006-06-02

Publications (2)

Publication Number Publication Date
WO2007143541A2 true WO2007143541A2 (fr) 2007-12-13
WO2007143541A3 WO2007143541A3 (fr) 2008-04-24

Family

ID=38694854

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2007/070208 WO2007143541A2 (fr) 2006-06-02 2007-06-01 DÉtecteur thermique pour agents chimiques ou biologiques

Country Status (1)

Country Link
WO (1) WO2007143541A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016050364A1 (fr) * 2014-09-30 2016-04-07 Sicpa Holding Sa Détection d'un marqueur dans un liquide

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004097373A2 (fr) * 2003-04-28 2004-11-11 Univ Arizona Biodetecteur thermoelectrique pour analytes dans un gaz

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004097373A2 (fr) * 2003-04-28 2004-11-11 Univ Arizona Biodetecteur thermoelectrique pour analytes dans un gaz

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HALL E A H: "Biosensoren" 1995, SPRINGER , XP002459818 ISBN: 3-540-57478-6 pages 388-409, paragraph 11.1 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016050364A1 (fr) * 2014-09-30 2016-04-07 Sicpa Holding Sa Détection d'un marqueur dans un liquide
EA026355B1 (ru) * 2014-09-30 2017-03-31 Сикпа Холдинг Са Обнаружение маркера в жидкости
US20170269056A1 (en) * 2014-09-30 2017-09-21 Sicpa Holding Sa Detecting a marker in a liquid
US10761080B2 (en) 2014-09-30 2020-09-01 Sicpa Holding Sa Detecting a marker in a liquid

Also Published As

Publication number Publication date
WO2007143541A3 (fr) 2008-04-24

Similar Documents

Publication Publication Date Title
US20080273572A1 (en) Thermal detector for chemical or biological agents
US6996478B2 (en) Multiple sensing system and device
Semancik et al. Kinetically controlled chemical sensing using micromachined structures
US6238085B1 (en) Differential thermal analysis sensor
EP1151272B1 (fr) Determination simultanee des proprietes cinetiques et d'equilibre
Comini et al. Solid state gas sensing
Penza et al. Application of principal component analysis and artificial neural networks to recognize the individual VOCs of methanol/2-propanol in a binary mixture by SAW multi-sensor array
US20020152037A1 (en) Multiple sensing system and device
US7034677B2 (en) Non-specific sensor array detectors
US6436346B1 (en) Micro-machined calorimetric biosensors
US20150268208A1 (en) Hybrid sensor array
US20050191757A1 (en) Method and apparatus for detecting humans and human remains
Espinosa et al. Drop-coated sensing layers on ultra low power hotplates for an RFID flexible tag microlab
WO2007143541A2 (fr) DÉtecteur thermique pour agents chimiques ou biologiques
Spannhake et al. Micro-fabrication of gas sensors
Kwon et al. MEMS-based condensation particle growth chip for optically measuring the airborne nanoparticle concentration
Meier et al. Detecting chemical hazards with temperature-programmed microsensors: overcoming complex analytical problems with multidimensional databases
WO1999040423A1 (fr) Reseau de capteurs pour le dedoublement des enantiomeres
Eklöv et al. Distributed chemical sensing
EP3265793B1 (fr) Système et procédé de détection de composés explosifs sur la base d'une déflagration rapide et d'une microcalorimétrie différentielle
Çimen et al. Sensors for the detection of food contaminants
Husni et al. Metal Oxides Semiconductor Sensors for Odor Classification
Singh et al. Modeling and Simulation of Micro/Nano Based Integrated Gas Sensor
Lawrence et al. Thermopile Sensors for the Detection of Airborne Pollutants
Batog et al. Chemical scanner for mobile robot navigation

Legal Events

Date Code Title Description
NENP Non-entry into the national phase in:

Ref country code: RU

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07798004

Country of ref document: EP

Kind code of ref document: A2