WO1996021521A1 - Procedes de revetement par gravure - Google Patents

Procedes de revetement par gravure Download PDF

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Publication number
WO1996021521A1
WO1996021521A1 PCT/US1996/000308 US9600308W WO9621521A1 WO 1996021521 A1 WO1996021521 A1 WO 1996021521A1 US 9600308 W US9600308 W US 9600308W WO 9621521 A1 WO9621521 A1 WO 9621521A1
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WIPO (PCT)
Prior art keywords
magnetic
substrate
pole
analyte
solution
Prior art date
Application number
PCT/US1996/000308
Other languages
English (en)
Inventor
Michael D. Cabelli
Suzanne S. Wiedman
Jerome L. Schwartz
Thomas L. Fare
John C. Silvia
Original Assignee
Ohmicron Technology, Inc.
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
Priority claimed from US08/488,133 external-priority patent/US5814376A/en
Application filed by Ohmicron Technology, Inc. filed Critical Ohmicron Technology, Inc.
Publication of WO1996021521A1 publication Critical patent/WO1996021521A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/28—Processes for applying liquids or other fluent materials performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/12—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a coating with specific electrical properties
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
    • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/001—Enzyme electrodes
    • C12Q1/002—Electrode membranes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/543—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals
    • G01N33/54366—Apparatus specially adapted for solid-phase testing
    • G01N33/54373—Apparatus specially adapted for solid-phase testing involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings
    • G01N33/5438—Electrodes

Definitions

  • the field of the invention is that of gravure processes for creating films of electroconductive polymers on solid surfaces. Additionally, the invention relates to the use of analyte-specific magnetic complexes and an electrode measurement system to detect an analyte.
  • Thin uniform films of electroconductive polymers on flexible substrates are an important component of certain types of electronic sensors that detect and measure the concentration of chemical and biochemical compounds.
  • Such sensors can be made by using electroconductive polymer films whose conductivity or capacitance changes when they are exposed to certain molecules, mechanical stress, or other factors. The response of a fil to the molecule, stress, or other factor, depends in part on the
  • test samples and standard amounts of test compounds Therefore there must be a
  • an organic solvent is required for the coating process. That requirement exists where (1) the polymer film is to be used in conjunction with an organic solvent.
  • the polymer cannot be water-soluble; otherwise it will dissolve
  • th .-n films onto flat and low profile substrates such as silicon wafers.
  • polyimides may be dissolved in an organic solvent and a polyimide film may be generated by spin coating.
  • spin coating the sensor
  • electrode surface is well-suited as a substrate for a thin polymer coating.
  • the present invention utilizes a gravure coating process. Gravure coating processes are discussed by H. Benkreira in Thin Film Coating. The Prn--pg ⁇ nr ⁇ nf h?
  • Antibodies are proteins that are produced in a- -mal.-- in response to molecules
  • An immunoassay is a quantitative or qualitative method of analysis which relies on the specific reaction between an
  • Immunoassays have been used for, among other things, environmental analysis using antibodies against herbicides, pesticides, or other environmental contaminants.
  • Two commonly used immunoassays formats are the sandwich assay and the competitive assay.
  • an analyte-reactive antibody is typically linked to a solid phase.
  • a reporter conjugate is required.
  • the reporter conjugate is an analyte-specific antibody linked to a reporter moiety capable of producing a detectable signal.
  • the sandwich assay the two antibodies can sandwich an analyte molecule, one antibody linking it to the solid phase, the other antibody generating a detectable signal.
  • the reporter conjugate is an analyte molecule (or
  • glucose oxidase coupled to the enzyme, glucose oxidase.
  • the entire magnetic complex was localized ax an electrosensor electrode surface.
  • the glucose oxidase converted ferrocene to a
  • the ferrocene was reoxidized at the electrosensor electrode surface as part of an electron transfer reaction, the resulting current being an indicator of the presence of analyte.
  • the electrode used by Yang et al. was made of metal and was /US96/00308
  • one invention is a continuous gravure coating process for
  • One of the present inventions is a method for detecting the presence of a specific analyte in a sample using an assay format in which magnetic components, such as magnetic particles with antibodies on their surfaces, provide an analyte- binding solid phase and the signal is generated by a dopant that changes the
  • a related invention is the use of a magnetic device comprised of an array of magnetic pole-pieces of high relative permeability alternating with appropriately
  • a further related invention is the use of cacodylate to generate a tr ⁇ odide
  • Fig. 1-A is a schematic view of a large-scale coater.
  • Fig. 2-A is a schematic view of a small-scale coater.
  • Fig. 3-A is a schematic view of a modified version of the small-scale coater depicted in
  • Fig. 1 is a perspective view of an electrochemical sensor.
  • Fig. 2 is an exploded perspective view of the sensor of Fig.l.
  • Fig. 3 is a top plan view of the sensor of Fig.l.
  • Fig. 4 is a cross-sectional view taken along axis C-C in Fig. 3, with a suspension of magnetic complexes visible in one of the three cells.
  • Fig. 5 is a cross-sectional view taken along axis D-D in Fig. 3, except that the electrode assembly and the pressure pad are not shown.
  • Fig. 6 is a front elevational view of the electrode assembly.
  • Fig. 7 is a top plan view of a portion of the electrode assembly; some of the dashed lines are added to identify schematically various functional areas of the electrodes.
  • Fig. 8 is a perspective view of a platform unit.
  • Fig. 9 is Fig. 8 modified in that part of the unit is cut away and in that a magnetic focussing device is on surface of the platform unit.
  • Fig. 10 is Fig. 9 modified in that the electrochemical sensor of Figs. 1-7 covers the magnetic focussing device seen in Fig. 9.
  • Fig. 11 is Fig. 1 modified to show the electrochemical sensor of Figs. 1-7 after it has been slid into the docking unit on the platform; the magnetic focussing device seen In
  • Fig. 9 is under the sensor and is hidden from view.
  • Fig. 12 is a bottom plan view of the platform unit shown in Fig. 8.
  • Fig. 13 is Fig. 8 shows the base the platform unit of Figs. 8-11.
  • Fig. 14 is a cross-sectional view, taken along the 14-14 axis shown in Fig. 13.
  • Fig. 15 is a cross-sectional view, taken along the 15-15 axis shown in Fig. 13.
  • Fig. 16 is a cross-sectional view, taken along the 16-16 axis shown in Fig. 13.
  • Fig. 17 is an exploded view of the magnetic field device embedded in the base unit of
  • Fig. 18 is a further exploded view of the magnetic field device of Fig. 17.
  • Fig. 19 is an exploded view showing selected components of the magnetic focussing device on the platform in Fig. 9.
  • Fig. 20 is a perspective view of the magnetic focussing device shown in Fig. 9.
  • Fig. 21 is cross-sectional view of the magnetic focussing device taken along axis 21-21
  • Fig. 22 is a cross-sectional view of the magnetic focussing device taken along axis 22-
  • Fig. 23 is a side elevation view of the an end pole-piece shown in Figs. 19 and 20.
  • Fig. 24 is Fig. 4 modified to show the presence of the magnet focussing device and
  • Fig. 25 is Fig. 5 modified to show the position of the magnetic focussing device when
  • the device is present as in Fig. 22.
  • Fig. 26 schematically illustrates how magnets and a pole piece combine to create a
  • Fig. 27 shows the percent positive responses as a function of analyte concentration in
  • Fig. 2S. shows the percent positive responses as a function on atrazine concentration in the analysis described in Example 2.
  • Electroconductive polymer is a polymer whose conductance or capacitance can be changed by chemical oxidization or reduction, thermal excitation, optical excitation, or other physical excitation. Electroconductive polymers and their mechanism of action are disclosed and discussed by M. G. Kanatzidis et a , Chemical & Engineering News. December 3, 1990, pp. 36-54. For sensors, o ⁇ idative doping
  • polymers that are electroconductive include, but are not limited to, polyacetylene, polypyrrole, polythiophene, poly(3- alkylthiophene), polyphenylene sulfide, polyphenylene vinylene, polythienylene vinylene, polyphenylene, polyisothianaphthene, polyazulene, polyfuran, polyaniline,
  • Dopants are molecular species that react with an electroconductive polymer so as to change the conductivity of that polymer.
  • Examples of dopants include, but are not limited to, I 3 ⁇ BF 4 " , C10 4 ' , FeCl 4 ' ,.N0PF 6 -, and N ⁇ .
  • An "electroconductive sensing element” is part of a sensor whose electrical properties change in response to the presence of an analyte. The change may be due to the analyte interacting directly with the sensing element or due to the analyte triggering the production or diminution of a substance that interacts directly with the sensing element.
  • sensing elements are those made of metal and those made of electroconductive polymers.
  • an "analyte” is a substance that an analytical procedure seeks to detect and quantify. Some analytes (e.g., Na * ) can interact directly with a sensing element and
  • Some analytes can be detected because they trigger or inhibit chemical or biochemical
  • An “electronic instrumentation unit” is any measuring device that responds to
  • test solution in a cell; e.g., changes in resistance, capacitance, field strength, ionic
  • an oven includes an oven, an air blower or fan, a heating element, a vacuum creation system,
  • a sheet that is horizontally disposed will have a top surface that is "upwardly
  • An "organic solvent” for use in the present inventions is one that comprises carbon atoms as part of its molecular make-up and which is at least partially not miscible with water but into which an electroconductive polymer of interest for use in
  • a “gravure roll” is a roller, normally metal, whose surface is characterized by a regular arrangement of precisely defined cavities created by chemical or mechanical engraving. Typical arrangements are categorized as quadrangular, tri-helical, or pyramidal. (See H. Benkreira, above). In the present examples, a quadrangular arrangement was used.
  • a coating solution is transferred directly to the surface to be coated.
  • the coating solution is first transferred from a gravure to a second roller, such as a rubber roller, which second roller then transfer--- the coating solution to the surface to be coated.
  • a "polymer”, in the case of a homopolymer, is considered to be any molecular chain where the repeating unit is present at least 20 times (i.e., the degree of polymerization is at least 20.) In cases where the polymer is a copolymer, each unit
  • Blocking refers to the phenomenon whereby a polymer film on a first sheet substrate is brought into contact with a polymer-free surface of a second sheet and, as a result, there is transfer of one or more blocks of film from the first sheet substrate to the second one.
  • the invention achieves the goal of producing large uniform, non-blocking electroconductive polymer films of desired thickness on a solid substrate in an economical manner.
  • the invention achieves its goal by using a direct gravure coatin process in combination with a continuously fed substrate; the process is enhanced when air is moved over the substrate in a direction counter to substrate motion soon
  • a drying oven is at a height greater than that of the gravure roll.
  • the substrate goes through a vertical orientation phase prior to the time
  • the substrate is coated on its
  • the invention is continuous gravure coating process for forming a fil of electroconductive polymer on the surface of a solid substrate, said
  • the substrate will be a flexible substrate.
  • a nonfiexible substrate such as glass.
  • substrate is treated the same as a flexible one, except that it cannot be rolled up.
  • Evidence for nonuniformity can be visual if the polymer has a color.
  • Nonuniformity within a specified area is then evidenced by variations in color, in the
  • a test for nonuniformity is ellipsometry or profilometry.
  • step (4) be accelerated by applying a drying means to
  • step (3) is completed and before step (4) is completed,
  • a first drying means is applied after step (3) is completed and prior to the time that the substrate surface has a vertical orientation; a second drying means is
  • the first drying means most preferably accomplishes sufficient drying so that fish-eyes and other nonuniformities do not occur prior to application of the second drying means.
  • the second drying means completes any uncompleted evaporation of the solvent from the
  • poly(3-n- hexylthiophene) a temperature over 160 °F is desirable to achieve firming, a temperature under of about 200 °F or less is desirable to avoid deformation of the polyester substrate.
  • the substrate will normally be a flexible sheet.
  • polyacetylene include, but are not limited to, polyacetylene, polypyrrole, polythiophene, poly(3- al ylthiophene), polyphenylene sulfide, polyphenylene vinylene, polythienylene vinylene, polyphenylene, polyisothianaphthene, polyazulene, polyfuran, polyaniline, and derivatives of the foregoing in which a repeating unit is substituted, for example poly(3-n-hexylthiophene).
  • substitution groups for such derivatives include polymers of alkyl (especially alkyl of 1 to 12 carbons), alkoxy (especially alkoxy of 1 to 3 carbons), cyclopentyl, cyclohexyl, benzyl, acetyl, p-tolyl, furyl, phenyl, and halo
  • Polymers of particular interest are polythiophene and its derivatives, especially polymer of alkylthiophene where the alkyl group has 1 to 12 carbons.
  • An electroconductive polymer of particular interest is one that, with at least one of the dopants, I 3 ⁇ BF 4 ⁇ C10 4 ⁇ FeCl 4 ', NOPF 6 ' , N «H 4 or protons, has a conductivity of at least 1 Siemens/cm when fully doped. polymer concentration for the gravure process
  • the polymer concentration may be as high as needed provided that the solutio is not too viscous to prevent uniform transfer of solution from the gravure roll across the substrate.
  • Any organic solvent can be used as long as the polymer is soluble in the solven
  • Solvent combinations of two or more of the above are usable.
  • the substrate can be any substrate with a surface for which the solvent has sufficient attraction so that the surface tension of the solvent does not prevent the solvent from spreading uniformly over the substrate surface.
  • Preferred substrates are any substrate with a surface for which the solvent has sufficient attraction so that the surface tension of the solvent does not prevent the solvent from spreading uniformly over the substrate surface.
  • plastics are hard, flexible organic solids such as plastics.
  • Preferred plastics are those with polyimide, polyester, or polycarbonate; however, a wide range of plastics can be used.
  • the surface will be metallized: partly or completely covered with a thin layer of metal (such as by sputtering or evaporating). Uniformity of film thickness is enhanced by plasma-cleaning the surface to be coated.
  • the oven normally is heated to temperatures as high as possible providing the temperature is not so high as to damage with the sheet or the polymer film.
  • oven temperatures of 78 °C to 95 °C were used successfully to achieve solvent evaporation.
  • Residence time at 95 °C in the oven ranged from 45 sec to 120 sec for successfully drying a toluene xylene (85/15, v/v) or a toluene xylene/indan (85/10/5, v v/v) solution.
  • Residence time at 95 °C in the oven ranged from 45 sec to 120 sec for successfully drying a toluene xylene (85/15, v/v) or a toluene xylene/indan (85/10/5, v v/v) solution.
  • a variety of shorter or longer residence times, although untested, would also be expected to be successful.
  • the oven residence time can be whatever is required to desolvate the polymer solution so that the coating is firm, nontacky (not sticky to the touch), and will not block onto the substrate. Use of coated substrates in sensors
  • a three-well cartridge-type sensor that can utilize a th. ⁇ metallized substrate
  • the competitive assay aspect of the invention is a method for detecting or measuring the concentration of an analyte with an electrochemical sensor, said sensor comprising a sensor cell for receiving a solution, said sensor cell comprising an
  • electrode assembly element that has a polymer surface, said polymer surface comprising an electroconductive polymer whose conductance or capacitance is changed when it reacts with a dopant, said method comprising the steps of:
  • an assay suspension comprising a first solution and a magnetic complex suspended in said first solution, said magnetic complex comprising an analyte bound to a magnetic component, said first solution comprising a reporter conjugate that is not bound to either said magnetic component or said analyte but is bindable to said magnetic component if analyte is not bound to said magnetic component,
  • reaction substrate such as glucose
  • reagents a possible set is exemplified in Examples 1 and 2 that in conjunction with said reporter conjugate can convert said reaction substrate to a dopant that changes the
  • step (3) measuring during step (3), after step (3), or both during and after step (3), the conductance or capacitance of the electrode assembly, wherein during step (3) the magnetic complex is kept by a magnetic force at a
  • step (1) as to the order of addition of the analyte, the magnetic component, and the reporter conjugate, in creating the suspension, it is often preferable that the analyte be added to a solution before the reporter conjugate or the magnetic component is added, and that the reporter conjugate be added to the solution before the magnetic component is added.
  • a sandwich assay aspect of the invention is a method for detecting or measuring the concentration of an analyte with an electrochemical sensor, said sensor comprising a sensor cell for receiving a solution, said sensor cell comprising an electrode assembly element that has a polymer surface, said polymer surface comprising an electroconductive polymer whose conductance or capacitance is changed when it reacts with a dopant, said method comprising the steps of:
  • said magnetic complex comprising a magnetic component, an analyte boun
  • said second solution comprising a reaction substrate and reagents that in conjunctio
  • reporter conjugate can convert a reaction substrate to a dopant that
  • step (b) the magnetic complex is kept by a magnetic force at a location at or near the
  • the magnetic component will comprise a magnetic particle and, attached to that particle, one or more moieties that will specifically bind to the analyte.
  • moieties include but are not limited to antibodies, nucleic acids (which hybridize to
  • nucleic add molecules of complementary base sequence ionophores, lectins, and
  • the reporter conjugate will comprise a reporter moiety bound to an analyte molecule or structural analog thereof.
  • the reporter conjugate will comprise a reporter moiety bound to a molecule that is capable of binding to the analyte. In either case, the reporter moiety will, in the detection step of the assay, be one that is required to produce a dopant that changes the conductance or capacitance of the electrode assembly.
  • step (3) is preferably achieved by adding the reaction substrate after adding the set of reagents that in conjunction with the reporter conjugate convert the reaction substrate to the dopant. It is also preferred that step (2), the separation step, be done while the magnetic complex is exposed to and localized by the magnetic
  • step (1) is added as follows:
  • the electrode assembly element forms part or all of the sensor cell floor.
  • the electrode assembly element is a probe that is inserted into the cell through the open top of the cell, and may be inserted at any time prior to step (4).
  • the probe may be inserted so that it is adjacent to and parallel to the wall of the cell and at right angles to the floor of the cell; in such a case, a magnetic device or devices would be parallel and close to that probe and wall rather than parallel and close to the floor of the cell.
  • the magnetic particles that are part of the magnetic components comprise a core magnetic material (for example, iron oxide) and a surface that is modified to
  • glucose oxidase glucose oxidase
  • glucose oxidase alternatives include alcohol oxidase. L-amino acid oxidase, cholesterol oxidase, creatine hydrolase, creatinase. sarcosine oxidase, galactose oxidase, B-galactosidase, and maltase.
  • three cells are run simultaneously in the same sensor.
  • One cell contains the sample (with an unknown analyte concentration), and the othe two cells contain solutions of known analyte concentration (one of which might have an analyte concentration equal to zero).
  • the change in conductance, capacitance, or current, of the sample cell is compared to the change in conductance, capacitance, or current, of cells with known analyte concentrations (standard concentrations) to determine if the sample is above or below the standard concentration.
  • the magnetic particles can be concentrated
  • the user can control the time at which the particles, and therefore the particle-bound antibodies enter into the reaction;
  • Magnetic particles can be uniformly coated and pipetted accurately in order
  • the user has a choice, for a given sensor, which analyte he or she wants to
  • reporter moieties such as enzymes located on particles of 1 ⁇ diameter (the approximate diameter of the magnetic particles used in the Examples) and thereby not directly located on the surface of the electrode would
  • a related invention is a method for detecting an analyte in an apparatus that comprises an array (e.g., a linear array) of receptacles of similar structure, each of
  • said receptacles comprising an inner surface, said method comprising the steps of
  • the magnetic force is created by a magnetic field device that comprises an array of magnetic pole-pieces, each consecutive pair of pole-pieces in the array separated from each other by a magnetic structural element (each of said pole-pieces preferably having a relative magnetic permeability greater than 10°).
  • the separation between successive pole-pieces in the array of pole-pieces is preferably the same as the separation between successive receptacles in the array of receptacles.
  • a further related invention is a separation apparatus for detecting an analyte in a receptacle, said apparatus comprising an array of receptacles of similar structure, each of said receptacles comprising an inner surface, said apparatus further comprising a magnetic field device that comprises an array of magnetic pole- pieces, each consecutive pair of pole-pieces in the array separated from each other by
  • each of said pole-pieces preferably having a relative magnetic permeability above 10 s , the
  • the magnetic structural elements in the structural element array are oriented
  • the pole pieces may be any one of the outer surfaces of the pole-pieces. Because those locations are also the locations of the magnetic particles in the cells of the electochemical sensor, the magnetic field device will exert the required magnetic force on those particles.
  • the pole pieces may be any one of the outer surfaces of the pole-pieces. Because those locations are also the locations of the magnetic particles in the cells of the electochemical sensor, the magnetic field device will exert the required magnetic force on those particles.
  • the pole pieces may be
  • Fig. 26 schematically illustrates how inserting a pole-piece (155) between, and
  • North poles designated by the letter "N" of two magnetic structural elements (156) creates a relatively large concentration of field lines (the dashed lines) at locations above the pole piece, i.e., the locations where there would be magnetic particles in the cells of the sensor.
  • the magnetic field device may be used in conjunction with a magnetic focussing device.
  • the magnetic focussing device may, for example, be attached to the underside of the electrochemical sensor or fit within the lower portion of the sensor.
  • the sensor along with the focussing device may then be slid back and forth along a surface, one position on the surface sufficiently removed from the magnetic field device so as to permit assay reactions to proceed with uniformly distributed magnetic particles, another position on the surface bringing it in proximity to both a docking unit for electrical measurements and a magnetic field device.
  • Example 2 A magnetic focussing device was used in Example 2, but not Example 1, below.
  • Example 1 the position of the magnetic field device relative to the sensor was similar to the position of the focussing device relative to the sensor in Example 2.
  • the pole-pieces of the magnetic field device have a relative magnetic permeability greater than 10 s .
  • Preferred materials for such pole-pieces are ferromagnetic ones such as silicon-iron, iron, steel, cobalt, nickel, magnetite, and some alloys of manganese. In the magnetic field device used in Example 2, the material was silicon-iron.
  • the relative magnetic permeability of a material (or medium) is the absolute permeability of the material (or medium) divided by the absolute permeability of vacuum.
  • Preferred material for magnetic structural elements are: neodymium-iron-boron (used in Examples 1 and 2), samarium cobalt, and other rare earth magnets.
  • pole-pieces have a low residual flux density and using nonmagnetic separator elements to separate those pole-pieces.
  • Preferred pole-pieces such as those used in Example 2, are silicon-iron alloys. Aluminum was used in the Example 2 as the material for the nonmagnetic
  • separators are preferred separator materials. Preferred separator materials also include plastics.
  • pole-pieces of the focussing device will be in an array spaced in the same manner as the pole-pieces of the magnetic field device; as a result, the pole-pieces of
  • the two devices may be aligned along side each other.
  • the ends of the magnetic field device are pole-pieces (as in the Figs. here).
  • slightly higher field gradients can be obtained by adding a magnetic structural element at each end of the device.
  • a further related invention is a method for detecting an analyte with an electrochemical sensor, said sensor comprising a sensor cell (but preferably three or more of identical shape and size) for receiving a solution, said sensor cell comprising an electrode assembly element that has a polymer surface, said polymer surface comprising an electroconductive polymer whose conductivity is changed when it reacts with triiodide, said method comprising the steps of
  • step (3) incubating the hydrogen peroxide in the presence of part or all of the solution created in step (1) so as to produce triiodide in the sensor cell,
  • the solution created in step (1) should be an aqueous solution.
  • a preferred solution is cacodylate in water. If the solution created in step (1) does not have catalytic activity that, in the presence of Ho0 2 , will result in the conversion of I " to I>, then the time period between step (1) and step (2) is preferably between one and two days. Whether or not the solution created in step (1) will require the one-to-two day incubation will depend on the batch of cacodylate purchased.
  • analytes include pesticides and herbicides, especially those that are inorganic or organic molecules (contains carbon and hydrogen; they may also contain other elements, such as but not limited to oxygen, nitrogen, halogens, sulfur and phosphorus) with a molecular weight of about 2000 daltons or less.
  • Antibodies against such analytes or their analogs can be produced by linking them to a carrier
  • bovine serum albumin such as bovine serum albumin and injecting animals so as to create polyclonal antibodies or monoclonal antibodies.
  • PCBs polynucleararomatic hydrocarbons
  • PAHs polynucleararomatic hydrocarbons
  • dinitrotoluene as well as benzene
  • Another general class of important analytes are those of medical diagnostic
  • microorganisms Alternatively, blood cell-typing may be done. Frequently, the
  • antibody's target is a protein or glycoprotein. Indeed, it can be of interest to test a
  • the invention can, however, be applied to the detection of almost any molecule or molecular compound, because it is possible to raise antibodies against the vast majority of substances and it is possible to 1-n glucose oxidase (or other enzymatic reporter moiety) to virtually all of those antibodies. In the case of most substances, it is expected that a conjugate between that substance and glucose oxidase (or other reporter enzyme) should be possible.
  • the magnetic particles bound to antibodies specific for the following compounds are obtainable from Ohmicron, Inc., Newtown, PA as part of their RaPIDassay® kits:
  • Alachlor, Aldicarb, Cyanazine, 2,4-D including the propylene glycol, ethyl, isopropyl, methyl, butyl,and sec-butyl esters), Atrazine, Benomyl, Carbendazim, Captan, Carbof ⁇ ran, Metolachlor, Procymidone, Carbaryl, Chlorothalonil, Chlorpyrifos. cyanazine, paraquat, pentachlorophenol, and polychlorinated hiphenyls.
  • Antibodies specific for a compound wn also be used to detect structural analogues of that compound providing the immunoreactivity for the antibodies is retained despite the structural variation.
  • conjugates of an analyte or an analogue
  • glucose oxidase that is a molecule structurally similar to the analyte) with glucose oxidase can be done by the same methods that were used to conjugate that analyte to a protein for purposes of creating an immunogen that generated antibodies against that analyte.
  • conjugates can be made by direct chemical reaction between the analyte
  • Atrazine (or an analogue) in which the atrazine's chlorine is replaced with a sulfur
  • an analyte (or an analogue) and the glucose oxidase can be
  • glucose oxidase or other enzyme can be any enzyme that can be used as a sandwich assay.
  • the glucose oxidase or other enzyme can be any enzyme that can be used as a sandwich assay.
  • an antibody as the analyte-sperific reagent.
  • analyte-speci-fic reagents are chelating agents for metals, ionophores, lectins for carbohydrates, streptavidin for biotin, and nudeic add molecules (for detecting nudeic add molecules of complementary base sequence).
  • the invention may be used with either heterogeneous (some of the materials and/or reagents used in the assay are removed prior to measuring the assay response, e.g., the conductance) or homogeneous (all materials and/or reagents used in the assay are still in the cell at the time the assay response, e.g., the conductance, is measured) formats. Analyte, conjugate, and antibody concentrations, order of addition and incubation times are optimized for different analytes. Similarly, the electrode geometry and cell volume may be changed to optimize a particular system. • RT.-F.PT OSENSOR AND MAGNETIC DEVICES
  • the electrosensor used in Examples 1 and 2 is illustrated in Figs. 1-7, 24 and 25.
  • the electrosensor used in Examples 1 and 2 had three cylindrical cells, the
  • electroconductive polymer-coated surface had an intermediate layer of strips of
  • the base, or lowest layer, of the assembly was made of a nonconducting polymer film (polyester) upon which the platinum strips had been deposited by a sputtering
  • the metal-striped base was coated with poly(3-n-hexylthiophene) solution so as to create a poly(3-n-hexylthiophene)-coated electrode.
  • the cylindrical cells were positioned with respect to the polymer-coated surface
  • FIG. 1 is a perspective view of the assembled sensor (2).
  • Figure 2 is an exploded cross-sectional view of the sensor.
  • Figs. 1 and 2 illustrate that the sensor is made of four parts: a cover unit (77), a three-hole gasket (30), a base unit (81), and a flat electrode assembly (10).
  • Fig. 1 the rims (20) of the three sensor cells are denoted.
  • Fig. 2 the platform (85) of the base unit, upon which the electrode assembly lies in the fully formed sensor, and a side slot (90) in the base unit, are shown.
  • the gasket (30) has three holes, each defined by a circular wall (32), the edge of each wall defined by a circular rim (31).
  • the gasket was 0.076 cm. thick and the electrode assembly was 0.0127 cm. thick, almost all of it due to the nonconductive
  • the thickness of the gasket and the electrode assembly may be drawn disproportionately large (for comparison, consider that the cell diameter is about 0.80 cm.) so as to assist the
  • the thickness of the electroconductive polymer layer and the thickness of the metal electrodes may be drawn disproportionately large compared to the thickness of the nonconductive film that forms the bottom layer.
  • the cover unit and the base unit were secured to each other so as to maintain
  • the cover unit was secured to the base unit by a securing means that had two components: a protruding securing component and a receiving securing component that was an opening through
  • the protruding component was a latch
  • Fig. 3 is a top plan view of the assembled electrochemical sensor showing the
  • Each cylinder wall (22) is part of a sensor cell that acts as a receptade within which assay steps ⁇ n be carried out.
  • the floor of each cell is provided by a portion of the electrode assembly element.
  • Electro assembly element A portion of the electrode assembly that was the floor of a sensor cell is referred to as an electrode assembly element.
  • the electrode assembly element (26) that was the floor of each cell.
  • one of the three identical elements defined a circular area on the electrode assembly
  • the electrode assembly elements, and therefore the receptades for which they supply a floor, are in a linear array; e.g., they fall on a line that passes through their
  • Each sensor cell was a 1.52 cm deep hollow cylinder seated on the electrode
  • Figures 4 and 5 show two cross-sectional views of the assembled sensor
  • Figure 4 is a cross-sectional view of the assembled sensor (taken along line C-C
  • Fig. 3 The fine structure of the electrode assembly (10), visible in the front elevational view of the electrode assembly has been omitted here. Also shown are a back protruding latch component (52) and, in cross-section, a side protruding latch component (50). The latch components fit through correspondingly positioned slots in the base unit. Also marked in Fig. 4 are the two side support walls (88), shown in cross-section, on the underside of the base unit. Eight magnetic complexes (46) shown for two of the eight complexes) suspended in solution (43) in one of the three cells are shown. The actual diameter of each particle was approximately one micron;
  • Figure 5 is a cross-sectional view of the assembled sensor (taken along line D-D
  • FIG. 54 shows a divider wall (54).
  • the lower edge (58) of the divider wall made essentially
  • Fig. 5 Also marked in Fig. 5 are the back support wall (87) and the front support wall (86), both shown in cross section. A magnetic focussing device will fit
  • Fig. 6 shows a front elevational view of the electrode assembly (10).
  • the upper surface (8) of the assembly was made of poly(3-n-hexylthiophene). Under this film lay
  • Fig. 7 is a top plan view of a portion of the electrode assembly some of the dashed lines are added to identify schematically various functional areas of the electrodes.
  • FIG. 7 shows in schematic fashion how each platinum electrode strip (6) of the electrode assembly (4) was divided into functional segments: a cell electrode
  • the cell electrode was a segment whose outer perimeter was defined by the inner front-to-back edge (106) of an electrode strip (6) and by a contact line (140) between the inner rim of a gasket and the upper electrode assembly surface (8) of that electrode.
  • the access electrode was a segment whose outer perimeter was defined by the inner front-to-back edge (106) of an electrode strip (6) and by a contact line (140) between the inner rim of a gasket and the upper electrode assembly surface (8) of that electrode.
  • electrode (114) in the Figure was a segment whose perimeter was defined by the front end (109) of an electrode strip (6), by the contact line (102) between the divider wall lower edge (58) and the electrode assembly upper surface (8), by the inner front-to- back edge (106) of the electrode strips, and by the outer front-to-back edge (108) of
  • the electrode strips are the electrode strips.
  • the gasket (e.g., 0.076 cm. thick), (30; in Fig. 2), was made of a polyethylene foam (Volara, grade 060A 0031WH). Its purpose was to create a better seal between the electrode assembly surface and the rims on the lower edge of the cylinder in order to prevent leakage. Its lower layer, not shown here, is identical to the top layer.
  • the electrode assembly measured 2.21 cm x 4.38 cm.
  • the assembly had a set of six metal strips (2.21 cm. x 0.679 cm.), and all strips were separated by a fixed spacing (0.0508 cm.)
  • Two narrow strips (2.21 cm. x 0.0254 cm.) separated the two outside metal strips from the edges of the electrode assembly.
  • Figures 8 - 23 illustrate a preferred embodiment of the magnetic field device and a preferred embodiment a magnetic focussing device.
  • Fig. 8 shows a platform unit (104) that contains a magnetic field device (130)
  • the device when it is in the platform but not over the field device.
  • the platform unit can consists of a base unit (151) and cover unit (153).
  • portion (120) of the cover unit covers the electronic docking unit.
  • the electronic docking unit such as a printed circuit board, and holes made in the base unit in order to accommodate those parts, are not shown in the Figures.
  • the exposed portion of the electrode assembly (10, see Figs. 1 and 2) can fit into the
  • three small LED's positioned on the top of the
  • the docking unit in parallel the sensor cells can be used to alert the user as to which sensor cell should receive materials so that the cells receive the materials in a desired
  • a device with multiple platform units in any desired arrangement can be any desired arrangement.
  • a magnetic focussing device (100) is on the platform unit's receiving surface (125) shown in Fig. 8 (but hidden from view in Fig. 9). An end rim (121) of the magnetic focussing device is visible.
  • Fig. 10 there is an electrochemical sensor (2) covering the focussing device (100) shown in Fig. 9.
  • the flat wing units (149) denoted in Fig. 10 are for holding the sensor in place when it is in the docking unit, espe ⁇ ally when the platform and
  • Fig. 11 shows a perspective view of the electrosensor unit (2) in the docking unit (120); the focussing device is within the lower portion of the electrosensor unit and is hidden from view. The sensor is directly over the magnetic field device.
  • the electrosensor unit together with the magnetic focussing device, can be slid from its position in Fig. 10 to its position in Fig. 11.
  • Fig. 12 is a bottom plan view of the platform unit (104) shown in Fig. 8 showing that unit's bottom surface (132).
  • the rectangular area (143) is the surface of a block-shaped volume (157; shown in Figs. 15 and 16) that can be made of a substance such as epoxy. The epoxy is added after the magnetic focussing device is inserted into the platform unit as part of the construction process of the unit.
  • the rectangular surface (143) forms part of the bottom surface (132).
  • Fig. 13 is a perspective view of the base (151) of the platform unit shown in Fig. 8.
  • the magnetic field device including its four rectangular cover units (133), are shown.
  • the cover units were made of aluminum, the same substance of which the base unit was made.
  • Fig. 14 is a cross-sectional view taken along fl- ⁇ ' s 14-14 shown in Fig. 13.
  • Fig. 14 shows the magnetic field device (130) within the base (151) of the platform unit.
  • the portion (122) of the base within which the magnetic field device is embedded is the portion (122) of the base within which the magnetic field device is embedded.
  • Fig. 15 is a cross-sectional view taken along axis 15-15 shown in Fig. 13. The
  • FIG. 1 shows the center pole-piece (124c) of the magnetic field device within the base
  • Fig. 16 is a cross-sectional view taken along axis 16-16 shown in Fig. 13. The
  • pole-pieces (124a-e) and magnetic structural elements (116a-d) that make up the magnetic field device are shown. Also shown is the block-shaped volume (157) that
  • each magnetic structural element was filled with epoxy.
  • a thin cover unit Above each magnetic structural element is a thin cover unit
  • Fig. 17 shows an exploded view of the magnetic field device .
  • the device is made of an array of five pole-pieces (124a-124e) and four magnetic structural
  • top surfaces (115a-115e) of the pole-pieces and the top surfaces (117a-d) of the magnetic structural elements are denoted.
  • the magnetic structural units are slightly shorter than the pole-pieces. As a result, when the structural elements are covered by cover units (133, see Figs. 13 and 16) the tops of the cover units will be at the same level as the tops of the pole pieces (See Figs. 13 and 16).
  • Each magnetic structural element consists of two magnets, the device is further
  • FIG. 18 also shows the five pole-pieces (124a- 124e)
  • each pole-piece and structural unit has two small protrusions; for the end pole-piece (124e), in each Figure, the protrusions (123) are denoted numerically.
  • the protrusions of the pole-pieces and structural units together create two rims along the magnetic field device, assisting in its positioning within the base unit of the platform.
  • Fig. 19 is an exploded view showing selected components of the magnetic
  • the focussing device the nonmagnetic base block (158), one of the three internal pole-
  • the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along the sides of the base block. It can be seen that the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along the sides of the base block. It can be seen that the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along the sides of the base block. It can be seen that the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along the sides of the base block. It can be seen that the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along the sides of the base block. It can be seen that the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along the sides of the base block. It can be seen that the internal pole piece (134a) has two small wings (141). Similarly, the rims (147) along
  • end pole piece has two small wings (159). The small wings rest on the top surface of
  • the end-pole piece also has a lower rim (145).
  • each side wall (142) of the non magnetic base block of the focussing device used in Example 2 was 0.215 inches; the length of each wall was
  • the width of the base block was 0.66 inches. Where the base block contained holes (139) the length of the hole was 0.48 inches and its thickness was 0.152 inches. The span across the top surface of an internal pole piece (e.g., 134a) /0 308
  • each end pole-piece was 0.555 inches, reaching essentially from rim (147) to rim (147) of the base block. At its bottom, the thickness of each end pole-piece was 0.131 inches, just above the rim (145) it was 0.071 inches.
  • Fig. 20 is a perspective view of the magnetic focussing device (100) shown in
  • Figs. 21 and 22 are cross-sectional views of the magnetic focussing device of Fig. 20, taken along axes 21-21 and 22-22, respectively. In both Fig. 21 and 22, the
  • end pole-pieces (135a-b) and the internal pole-pieces (134a-c) are shown. Also shown are the regions (137) of the base block (158) that separate the pole-pieces from each other, thereby functioning as non-magnetic separator elements.
  • pole-pieces of the focussing device are in a linear array.
  • Fig. 23 is a side elevational view of an end pole-piece (135b) of the magnetic field device.
  • the wing (159) and the lower rim (145) of the pole-piece are denoted.
  • Fig. 24 is Fig. 4 modified to schematically show how the magnetic focussing device (100) fits under the sensor (2) and the position of the magnetic field device (130) relative to the focussing device when the sensor and focussing device are directly over the field device as in Fig. 11.
  • the cross-sectional views of the focussing device and the field device are the same as those shown in Figs. 21 and 16, respectively.
  • Three of the pole-pieces (124a, 124c, 124e) and two of the magnetic structural units (116b, 116c) of the magnetic field device are denoted.
  • Three pole- pieces (135a, 134b, 135b) of the focussing device are denoted.
  • the pole-pieces of the field device are aligned with both the pole-pieces of the focussing device and the
  • Fig. 24 is a cross-sectional view, it actually shows half of each cell.
  • Fig. 24 shows the localizing effect the magnetic field device, in conjunction with the
  • magnetic focussing device has on the magnetic complexes.
  • Fig. 25 is Fig. 5 modified to schematically show how the magnet focussing
  • the electroconductive polymer was deposited onto a metallized polyester roll using a
  • the electrode assembly was made by first preparing a thin sheet (about 0.005 in. thick) of polyester (ICI-ST507 heat stabilized PET) with a silk-screen image of the
  • desired line pattern comprising a water soluble paste, and then sputtering a platinum
  • Electrodes were fabricated by sputter-deposition of platinum to a thickness of approx 80 n in high-vacuum onto polyester film rolls.
  • the metal was pattern- defined using modified lithographic techniques in which a water soluble paste was applied to areas ultimately free of metal (in those areas, the metal will deposit on the paste instead of the polyester film), dried, and then after the deposition of metal, the paste was washed out along with its metal coating. This resulted in a parallel array of metal electrode strips and spacings. Electrode strip widths (0.68 cm) and spariags (0.05 cm) were patterned to be on-center with standard electrical connectors in an electronic instrumentation unit.
  • the assembly was overlaid with a coating of poly(3-n-hexylthiophene) as described herein.
  • An electronic instrumentation unit was used to measure changes in electronic current flow.
  • An ac voltage (sine wave at 10 Hz) with a 200 V peak was generated by a wave generator and applied to one electrode.
  • Sensors were connected via their access electrodes to electrical connectors in the docking unit and thereby to an electronic instrumentation unit for measurement.
  • An electrode connector of the doclring unit scraped off the polymer -from an access electrode surface during that electrode's insertion into that connector.
  • the output current in the milliampere range, was converted to a millivolt value using a current-to-voltage converter.
  • the creation of dopant in the cell was determined. Because the applied voltage is constant, the conductance or capadtance can be derived from the measured current.
  • the sensor with its magnetic focussing device inserted in its lower portion can be any sensor with its magnetic focussing device inserted in its lower portion.
  • Guides may be added to the platform surface to assist positioning.
  • a thin sheet of slippery plastic or lubricant may be added to the surface of the
  • the large-scale apparatus is shown in Fig. 1-A.
  • the apparatus had an unwind role (1) which was the source of the substrate (20) that was wound around the unwind role.
  • the substrate passed over a first directional roll (2) used to adjust the direction in which the substrate moved off the unwind roll.
  • the substrate still free of polymer solution or film, passed over a second directional roll (3) before
  • the gravure roll transferred a polymer solution to the downwardly oriented side of the substrate.
  • the polymer solution was present in a trough (22) to which it was continuously fed by a dropping
  • the substrate then traveled through a horizontal mode followed by contact with a fourth directional roll (7).
  • the fourth directional roll turned the substrate, with polymer solution on its surface, into a vertical orientation phase.
  • the degree of vertical orientation in the vertical orientation phase is equal to the angle between the substrate and the horizontal. That angle can vary from just greater than zero degrees to 90 degrees; in the case of the commerdal coater, it was about 80 degrees.
  • the coated substrate then came in contact with a fifth directional roll (8) that turned it into a substantially horizontal mode for passage through a drying oven (24).
  • the drying oven had a series of support rolls (six to fifteen) of which the first (9a) and last (9b) are denoted. As the substrate passed through the drying oven, any residual solvent in which the polymer was dissolved evaporated. Drying was assisted by an
  • the substrate then came into contact with a second drive roll (13) before
  • the gravure roll (5) had a 120 Q cell size in contact with a hard rubber
  • the processes of the current invention can, however, be carried out with other cell sizes.
  • the cell size which controls the amount of solution transferred per square inch of substrate, the line speed, and the polymer concentration in the
  • polymer solution determine the final weight of polymer per square inch of polymer film (the "coating weight"). For example, a smaller cell size gravure and a higher polymer concentration in the solution can produce the same coating weight as a larger cell size gravure and a lower polymer concentration in the solution.
  • the gravure pattern on the large scale coater was a quadrangular pattern utilizing a cell size of 120 Q, each cell with an area of 3.92 x 10" 4 cm 2 , a depth of 120 microns (1.2 x 10 '2 cm), and a cell volume per unit area of 28.5 cubic billion microns per square inch.
  • the gravure pattern on the small scale coater was a quadrangular pattern utilizing a cell size of 110 Q, each cell with an area of 4.84 x 10"* cm 2 , a depth of 98 microns (0.98 x 10 '2 cm), and a cell volume per unit area of 25.5 cubic billion microns per square inch.
  • Fig. 2-A is a schematic view of a small-scale coater.
  • the small scale apparatus had essentially the same elements as the large scale apparatus except that it did not have the fourth (7) and seventh (11) directional rolls, and had an air dryer (blower) instead of an oven. Tension on the substrate after the gravure nip roll is not provided by main drive rolls (12) and (13) as is the case in the
  • the blower (not shown) blew air into a manifold (not shown) that directed the air through four air bars (30) from which it blew onto the coated substrate surface.
  • the gravure roll (5) was not a drive roll. Pressure was created between the gravure roll and the substrate surface by means of a counterweight arrangement (not shown) that pushed the gravure roll in an upward direction.
  • the rolls (6), (8), (9a), and (13) were connected by a timing belt (not shown in Fig. 2-A).
  • the main drive was connected to the nip roll (6), the unwind roll (1) was connected to an unwind tensioner (not shown), and generally it had smaller dimensions (See Table 1).
  • the air dryer had a 3000 rpm air moving unit that produced 18 of a horsepower and blew air through four slots whose areas totalled together 1.5 square inches. At the end of each run on the small scale coater, the coated substrate was moved to an oven and baked at 90°C for 15 minutes.
  • the substrate was a heat-stabilized polyester film (polyethylene terephthalate (PET)) that was 0.005 inches thick (+/- 10%) and that had been metallized in a pattern consisting of metallized stripes (sputtered platinum or aluminum.) 0.2675 inches wide and usable as electrodes alternating with gaps (nonmetallized sections) 0.020 inches wide.
  • PET polyethylene terephthalate
  • Other preferred plastic substrates include a polyimide such as Kapton®. The substrate must be able to withstand the highest temperatures used i
  • the coating process and also provide a uniform coating surface.
  • Metallization of the substrate is not required for creating a polymer film. However, a long sheet of
  • substrate with a repeating metallized pattern can be cut into small pieces, each with the same metallized pattern, and the metallized pattern used as parts of an electrica
  • the width of the substrate was 3.75 inches on the small scale coater and 11.75
  • the substrate was plasma-cleaned and inertly bagged under a nitrogen
  • the substrate length can be as small as desired by splicing the substrate to be coated into a longer sheet of substrate. For example, in one run on the small scale coater, a patterned metallized polyester substrate to be coated and measuring 6
  • the substrate length can be as long as can be adequately handled (several hundred feet, for example, in some large scale coater runs).
  • the polymer used in the examples was poly(3-n-hexylthiophene) with an average degree of polymerization of about 1000.
  • the nature of the invention is such that is applicable to a wide variety of polymers.
  • the polymer was synthesized by adding, in an inert atmosphere at 5 °C, over 0.5 to 1 hour (times and other conditions denoted herein for polymer preparation are representative of conditions used but were not always exactly followed), the monomer dissolved in chloroform to a solution of ferric chloride in chloroform (final ratio of 0.5 kg anhydrous ferric chloride/5 to 6 L of chloroform).
  • the molar ratio of catalyst to 3- n-hexylthiophene monomer was 4 to 1. Incubation was continued with stirring for about 2 hour. The majority of the ferric chloride was then extracted by multiple extractions with distilled water.
  • the polymer was predpitated with methanol.
  • the solid polymer was extracted in a Soxhlet apparatus with acetone for one week.
  • the polymer was dissolved in toluene and washed with water. It was then filtered over a bed of Celite on top of alumina. It was then predpitated with methanol, collected by filtration, dried under vacuum, and stored as necessary in the dark.
  • the poly(3-hexylthiophene) was dissolved in a fresh solvent blend under nitrogen over the course of 24 hours to a concentration of 20 mg ml.
  • thickeners surfactants, modifiers, antioxidants, stabilizers, copolymers, dopants, or
  • the solution was centrifuged, the supernatant collected and, using a coating
  • the solution was introduced to the coating trough (22), the nip roll was
  • the coated and dried film passed through the drive and rolls to the wind-up roll.
  • the film was immediately unwound from the wind-up roll, sheeted, and interleaved with a deaned polyethylene foam material, although it can be stored for at least four months in the rolled up state. Further converting (cutting) reduced the film to the appropriate size for incorporation into an electrochemical biosensor.
  • Magnetic components Magnetic particles coupled to anti-atrazine antibody were obtained from Ohmicron's RaPID Assays Division and are part of commertial
  • Atrazine-glucose oxidase conjugate was purchased from Biodesign (RR#2, Box 1048, Kennebunkport, Maine 04046).
  • Each sensor had three cells: to start the assay, 200 ⁇ l of the sample was added to the center cell and 200 ⁇ l of standard were added to each end cell.
  • the assay was set up as if the critical concentration for distinguishing between a positive and a negative result was 2.5 ppb.
  • the known concentration of atrazine in both side cells was 2.5 ppb.
  • the electronics were adjusted so that a response from a sample in the middle cell would be recorded as a positive result if it was less than or equal to the average response of the side cells and recorded as a negative result if it was greater than the average response of the side cells. This arrangement allowed samples of 3 ppb or greater to be recorded as a positive result 80 percent or more of the time.
  • An aliquot of 200 ⁇ l of the concentrated magnetic components was pipetted into each cell and allowed to incubate with atrazine for one minute. Next, 50 ⁇ l of glucose oxidase-labelled
  • Atrazine conjugate were added to each cell and allowed to incubate for 4 minutes.
  • Conjugate buffer 500 mM cacodylate, 20% glycerol; 10% ethanol; 1% BSA
  • Magnetic Particle Buffer 250 mM Tris, 150 mM NaCl, 1 mM EDTA, 0.1 %
  • a magnetic field device was aligned under the cells. That device was different, however, tha-n the one in the Figures and was bar-shaped to fit under
  • the device consisted of three disk-shaped magnets spaced to align with the sensor cells.
  • the magnetic field device was used for one minute to pull the magnetic partides down to the electrode surface; the magnets remained in
  • the senor After incubation, with the magnetic field device still keeping the magnetic components and complexes at the electrode surface, the sensor was turned upside- down to empty the solutions in the cells; keeping the sensor inverted, the top of the sensor was brought down with a rapid, vertical motion against absorbent towels spread on a table to blot excess solution.
  • reaction substrate glucose
  • other reagents needed so that the reaction substrate (glucose) and other reagents needed so that the reaction substrate (glucose) and other reagents needed so that the reaction substrate (glucose) and other reagents needed so that the reaction substrate (glucose) and other reagents needed so that the reaction substrate (glucose) and other reagents needed so that the reaction substrate (glucose) and other reagents needed so that the
  • reporter conjugate if present would convert the reaction substrate to a dopant
  • Triiodide, I 3 generated from the ensuing reaction caused a
  • instrumentation unit compared the response of the sample to the average of the
  • Fig. 27 For each point on the graph in Fig. 27, 10-20 samples were tested. In Fig. 27, it can be seen that there were 10 percent false negatives when the concentration of atrazine in the test sample (center cell) was 3 ppb and none when that concentration was 4 ppb. There were 15 percent false positives when the concentration of atrazine in the test sample was 2 ppb and no false positives when that concentration was 1 ppb. The percentage of false negatives and false positives were suffidently low that the assay was a useful one. (Similar results were obtained when the magnetic field device and magnetic focussing devices of the kind shown the Figs. 8-25 were used.)
  • drying means oven oven temperature: 200 °F oven residence time: 90 seconds line speed for substrate: 10 ft min substrate composition: 5 mil heat-stabilized polyester metal sputtered for metallization: platinum
  • chatter lines (roughly 140 inch thick) were present every 1/5 to 1/4 inches running parallel to the roller axes.
  • the chatter lines are probably the result of machine vibration. Chatter lines, because they are essentially uniform across the width of the substrate, are probably not a significant contributor to nonuniformity of sensor response, as the electrodes can be cut from the substrate sheets in a manner that each well of the sensor has the
  • Substrate tension lines were present every 2 to 4 inches roughly parallel to the roller axes and at one side of the substrate. The tension lines are probably due to periodic pulls and shifts on the substrate.
  • Each fisheye was a series of concentric rings alternating in color intensity from lighter to darker (typically the central circle will be dark and have a diameter of about 1/16 inch, this will be surrounded by a Eghter colored ring with an external diameter of about 1/8 inches, and that will be surrounded by a ring with an outer diameter of about 3/16 inches, the latter ring marking the outer edge of the fisheye.)
  • the amount of fisheyes were relatively infrequent (about- one per 3 square inches).
  • Example 3 This example was performed under essentially the same conditions as Example 3 except that the line speed was varied between 3 and 25 feet per minute
  • Example 3 was repeated except that the concentration of the coating solution was varied between 15 and 25 mg ml and the oven temperature was about 78 C C. It was observed that higher concentrations produce thicker films and lower concentrations produce thinner films. Higher and lower concentrations of polyO-n-hexylthiophene) than those used in this example may be coated but they are generally not as preferred. As the films became thinner they evidenced more tendency towards nonuniformity.
  • Example 3 was repeated except that the binary solvent formulation used to dissolve and dilute the polymer was altered to indude a third solvent, indan, and the oven temperature was about 78 °C. That mixture was formulated in the
  • the coating process was done on the same day and ambient conditions as
  • polymer poly(3-n-hexylthiophene) polymer concentration about 20 mg ml
  • An auxilary air dryer sent air through a single air bar (40) with an intensity similar to a single air bar in Fig. 2-A.
  • the direction of air flow was opposite to the direction of movement of the substrate.
  • the air flow was directed against the polymer solution on the downwardly oriented side of the substrate, just as the substrate left the gravure roll (5).
  • the air bars (30) were not used.

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Abstract

L'invention se rapporte à un procédé de revêtement par gravure destiné à produire des films polymères électroconducteurs, ainsi qu'à un procédé de détection de la présence d'un analyte spécifique dans un échantillon à l'aide d'un format de dosage immunologique dans lequel des particules magnétiques forment la phase solide et où le signal est un agent de dopage pouvant être détecté par la variation de conductivité d'un polymère électroconducteur recouvrant une électrode. L'invention s rapporte, de plus, à des dispositifs magnétiques servant à créer une force importante sur les particules et à l'utilisation de cacodylate pour catalyser la production d'un agent de dopage, le triiodure.
PCT/US1996/000308 1995-01-13 1996-01-11 Procedes de revetement par gravure WO1996021521A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US37251595A 1995-01-13 1995-01-13
US08/372,515 1995-01-13
US08/488,133 US5814376A (en) 1995-01-13 1995-06-07 Gravure coating systems and magnetic particles in electrochemical sensors
US08/488,133 1995-06-07
US51476595A 1995-08-14 1995-08-14
US08/514,765 1995-08-14

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WO1996021521A1 true WO1996021521A1 (fr) 1996-07-18

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WO2005011834A2 (fr) * 2003-08-01 2005-02-10 Bg Research Limited Ameliorations apportees a des cuves de reaction

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US4520048A (en) * 1983-01-17 1985-05-28 International Octrooi Maatschappij "Octropa" B.V. Method and apparatus for coating paper and the like
US4704296A (en) * 1984-09-28 1987-11-03 Magna-Graphics Corporation Web coating method and apparatus
US4738879A (en) * 1986-07-02 1988-04-19 Xerox Corporation Coating system
US5231523A (en) * 1988-08-03 1993-07-27 Tdk Corporation Liquid crystal elements and conductive organic compound film-forming compositions

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Publication number Priority date Publication date Assignee Title
US4097417A (en) * 1974-05-02 1978-06-27 National Starch And Chemical Corporation Photocurable electroconductive coating composition
US4520048A (en) * 1983-01-17 1985-05-28 International Octrooi Maatschappij "Octropa" B.V. Method and apparatus for coating paper and the like
US4704296A (en) * 1984-09-28 1987-11-03 Magna-Graphics Corporation Web coating method and apparatus
US4738879A (en) * 1986-07-02 1988-04-19 Xerox Corporation Coating system
US5231523A (en) * 1988-08-03 1993-07-27 Tdk Corporation Liquid crystal elements and conductive organic compound film-forming compositions

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005011834A2 (fr) * 2003-08-01 2005-02-10 Bg Research Limited Ameliorations apportees a des cuves de reaction
WO2005011834A3 (fr) * 2003-08-01 2005-05-06 Bg Res Ltd Ameliorations apportees a des cuves de reaction

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