Abstract: A micro flow system is provided for separating particles, comprising a microfabricated member having a flow channel (5) defined therein for guiding a flow of a fluid containing the particles through the flow channel, first inlet means (2) positioned at one end of the flow channel for entering the fluid into the flow channel, first outlet means (7) positioned at the other end of the flow channel for discharging the fluid from the flow channel, the flow of the fluid containing the particles being controlled in such a way that one particle at the time passes a cross section of the flow channel, the member being positioned in a field that is substantially perpendicular to a longitudinal axis of the flow channel so that particles residing in the flow channel and being susceptible to the field across the flow channel are deflected in the direction of the field.

Abstract: In a process for the quantitative optical analysis of biological cells labelled with a fluorescent dye, the sensitivity of analytical detection can be considerably improved if a masking dye, which absorbs the excitation light for the fluorescent dye and/or its emission light is added to the solution surrounding the biological cells and/or if a separating layer permeable to the solution and absorbing and/or reflecting the excitation light or the emission light is applied to a layer of the biological cells at the bottom of a reaction vessel. This process can also be used for improving the sensitivity in the quantitative optical analysis of a luminescent biological cell layer. Analogously, these process principles can also be used in receptor studies for the masking of the interfering background radiation in the quantitative optical analysis of fluorescently or luminescently labelled reaction components.

Abstract: This invention provides methods of retentate chromatography for resolving analytes in a sample. The methods involve adsorbing the analytes to a substrate under a plurality of different selectivity conditions, and detecting the analytes retained on the substrate by desorption spectrometry. The methods are useful in biology and medicine, including clinical diagnostics and drug discovery.

Abstract: For processing of substances in the reservoir (3) of a microdroplet dosing device (1), movement of a solid carrier material with a binding-active surface takes place in the reservoir, and binding of the substance takes place on the surface of the carrier material which comprises magnetic particles (7) or a carrier pad.

Abstract: A specific coupling reaction measuring method of this invention for measuring a content of a subject substance in a sample includes the steps of (a) constructing a reaction system including the sample and a magnetic particle on which a specific coupling substance for specifically coupling with the subject substance is immobilized; (b) measuring an optical characteristic of the reaction system; and (c) removing, from the reaction system, an agglutination complex including the subject substance, the specific coupling substance and the magnetic particle by utilizing magnetic force.

Abstract: An apparatus to measure micro-forces includes a cantilever palette with a set of cantilever array blocks. Each cantilever array block includes a set of cantilevers, with each cantilever including a set of cantilever fingers surrounded by a frame with frame fingers. The cantilever fingers and the frame fingers form a diffraction grating. Each cantilever array block is configured to be responsive to a predetermined micro-force, such that cantilevers of the cantilever array block deflect in the presence of the predetermined micro-force, which causes the diffraction grating to diffract light and thereby provide a visual indication of the presence of the predetermined micro-force.

Abstract: A primary antibody bead suspension for an enzyme-linked immunoassay (“ELISA”) procedure is formed of a quantity of primary antibody coated magnetic beads (3) uniformly dispersed and held in suspension (9) by a thixotropic non-Newtonian fluid (1). To remove the thixotropic non-Newtonian fluid prior to application in the ELISA procedure, a magnet (12) is placed against the side of the non-magnetic vessel (9) holding the suspension to draw the magnetic beads against the side while the thixotropic fluid is washed away by pumping (14,16,15& 17) and replaced by a saline buffer solution.

Abstract: Carriers hold remote-acting bodies which can be manipulated by a remote force, and also hold a micro-substance which is a target substance of an assay. The remote-acting bodies are manipulated in order to control the positions of the micro-substances, so as to execute assays for various target substances efficiently, at low cost, easily, and reliably. Various aspects of interest include the carriers which hold the micro-substances, a system suspending the carriers, an apparatus for manipulating the carriers, and a method of controlling the position of the carriers.

Abstract: The invention provides methods and compositions for azide tagging of biomolecules. In one embodiment of the invention, proteins are tagged by metabolic incorporation of prenylated azido-analog substrates. Examples of such analogs are azido farnesyl diphosphate and azido farnesyl alcohol. The azido moiety in the resulting modified proteins provides an affinity tag, which can be chemoselectively captured by an azide-specific conjugation reaction, such as the Staudinger reaction, using a phosphine capture reagent. When the capture agent is biotinylated, the resulting conjugates can be detected and affinity-purified by streptavidin-linked- HRP and streptavidin-conjugated agarose beads, respectively. The invention allows detection and isolation of proteins with high yield, high specificity, and low contamination without harsh treatment of proteins.

Abstract: In a process for the quantitative optical analysis of fluorescently labelled biological cells 5, a cell layer on a transparent support at the bottom 2 of a reaction vessel 1 is in contact with a solution 3 containing the fluorescent dye 4. The sensitivity of analytical detection can be considerably improved if to the fluorescent dye 4 already present in addition a masking dye 9, which absorbs the excitation light 6 for the fluorescent dye 4 and/or its emission light 7, is added to the solution 3 and/or if a separating layer 10 permeable to the solution and absorbing and/or reflecting the excitation light 6 or the emission light 7 is applied to the cell layer at the bottom 2. This process can also be used for improving the sensitivity in the quantitative optical analysis of a luminescent biological cell layer. The separating layer 10 must in this case be composed such that it has a high power of reflection for the luminescent light 11.

Abstract: Separation apparatus and method for separating magnetic and/or magnetically-labeled particles from a test medium. Test medium within a reaction chamber is caused to flow past a collecting surface, and a high-gradient magnetic field is applied to the surface to capture magnetically responsive particles in the test medium. The particles are deflected toward the collection surface by baffles, a spinner, or a sprayer, or are funneled past the surface by a plunger operable to be displaced into close proximity to the surface to provide a narrow flow path for the particle-laden test medium. The particles normally suspended in the medium are separated out of suspension by adhesion to the collection surface. The particles may be resuspended by removal of the surface from the high-gradient field, or removal of the high-gradient field from the surface. The collection surface is a thin-walled non-magnetic material having a plurality of magnetic pole faces positioned therearound.

Abstract: Graphitic nanotubes, which include tubular fullerenes (commonly called “buckytubes”) and fibrils, which are functionalized by chemical substitution, are used as solid supports in electrogenerated chemiluminescence assays. The graphitic nanotubes are chemically modified with functional group biomolecules prior to use in an assay. Association of electrochemiluminescent ruthenium complexes with the functional group biomolecule-modified nanotubes permits detection of molecules including nucleic acids, antigens, enzymes, and enzyme substrates by multiple formats.

Abstract: Method and device for magnetic detection of binding of biological molecules on a biochip in which a magnetoresistive sensor device measures an areal density of magnetic nanoparticles on a micro-array, the magnetic nanoparticles being directly or indirectly coupled to a target sample. The magnetoresistive sensor device includes a substrate having attached thereto binding sites able to selectively bind the target sample, and a magnetoresistive sensor for detecting the magnetic field of the nanoparticles coupled to the target sample. The magnetoresistive sensor includes a plurality of magnetoresistive sensing elements, the width and length dimensions of which are at least a factor 10 or more, preferably a factor 100 or more larger than the diameter of the nanoparticles.

Abstract: A method for producing a derivatized aldehydic support matrix material includes activating surface hydroxyl groups on the support matrix material and reacting the activated hydroxyl groups with an aldehydic alkoxy silane. The derivatized aldehydic support matrix material produced is useful for immobilizing bio-molecules in biological applications.

Abstract: A method and apparatus for the manipulation of colloidal particulates and biomolecules at the interface between an insulating electrode such as silicon oxide and an electrolyte solution. Light-controlled electrokinetic assembly of particles near surfaces relies on the combination of three functional elements: the AC electric field-induced assembly of planar aggregates; the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The present invention provides a set of fundamental operations enabling interactive control over the creation and placement of planar arrays of several types of particles and biomolecules and the manipulation of array shape and size. The present invention enables sample preparation and handling for diagnostic assays and biochemical analysis in an array format, and the functional integration of these operations.

Abstract: The invention relates to a process for quantitative detection of analytes in liquid and solid phases with the aid of binding remanence measurement, compounds that are suitable for this purpose, and their use in analytic chemistry.

Abstract: The invention relates to analytical methods in which the partition of a labeled substance between a liquid and a solid phase is determined. The assays include solid-phase reagents which can be particulate or monolithic such as, for example, a coated tube. Assays of this type are known per se to the person skilled in the art and include immunoassays and immunometric assays.

Abstract: Superparamagnetic (“SPM”) subunits of 1–30 nm average mean diameter (e.g. ferro fluid) subparticles are treated with a magnetically noninterfering substance capable of coating and covering them (e.g, BSA) and they spontaneously form agglomerates of about 100 nm to about 450 nm or higher average mean diameter and are then used to form complexes with target biological ligands such as viruses, contained in large volumes of liquid. The complexes are subjected to the gradient intensity of a strong magnetic field, and excess liquid is removed, where upon an immunochromatographic assay is conducted to determine the identity and/or amount of target ligand present, in which operation SPM particles that bonded to the ligand function as tags for ligand detection.

Abstract: This invention relates generally to the field of moiety or molecule isolation, detection and manipulation and library synthesis. In particular, the invention provides a microdevice, which microdevice comprises: a) a magnetizable substance; and b) a photorecognizable coding pattern, wherein said microdevice has a preferential axis of magnetization. Systems and methods for isolating, detecting and manipulating moieties and synthesizing libraries using the microdevices are also provided.

Abstract: An improved cartridge for holding a fluid sample with a small volume is disclosed herein. The cartridge has a test chamber and a vestibule through which the test fluids are inserted into the test chamber. Improved grips are flared-out to aid manipulation. The handle portion is reinforced to prevent flexing, and a prefabricated trough along the edge of the land surface prevents introduction of the adhesive into the region for analysis. The cartridge has a stopper having a dual sealing mechanism, which seals the test chamber inlet between the vestibule and the test chamber, and the mouth of the vestibule so that when the stopper is in place, the test chamber is closed to the admission of air or other contaminants. The vestibule is similarly closed against escape of the overflow from the test chamber. The stopper is composed of a single elastomer. An improved locking mechanism has two flexible walls on either side of the handhold that locks into their respective keepers on the cartridge to provide a secure lock.

Abstract: Disclosed are devices for detecting the presence of a preselected analyte in a fluid sample. The devices comprise a substrate microfabricated to define a sample inlet port, and a mesoscale flow system that includes a sample flow channel extending from the inlet port. The mesoscale flow system further includes an analyte detection region in fluid communication with the flow channel comprised of a binding moiety for specifically binding the analyte. The detection region is constructed with a mesoscale dimension sufficiently small to enhance binding of the binding moiety and the analyte. The binding moiety may be immobilized in the detection region. The mesoscale detection systems of the invention may be used in a wide range of applications, including the detection of cells or macromolecules, or for monitoring reactions or cell culture growth.

Abstract: The invention relates to a concentration device using magnetic particles and a method therefor aimed at performing concentration of a large volume of liquid efficiently and reliably with a simple structure and on a small device scale. The construction involves having: a liquid suction passage in which liquid can pass through only in a suction direction; a liquid discharge passage in which liquid can pass through only in a discharge direction; a magnetic force device which can exert a magnetic field from outside of the liquid passage on at least one liquid passage thereof or remove the magnetic field, and which can separate magnetic particles having directly or indirectly captured a target substance suspended in the liquid by having the magnetic particles adhere to the inner wall of the liquid passage; a storage section communicated with each liquid passage, for storing the sucked liquid; and a pressure adjustment device for sucking and discharging the liquid by adjusting the pressure in the storage section.

Abstract: A method and apparatus for the qualitative and quantitative detection of analytes is disclosed in which in the detection of an analyte in a sample, an elongated migration base is used, in which there is an area for binding a magnetically marked analyte, and in which, in stages the sample is absorbed into the migration base and the sample spreads on the migration base into the area. The elongated migration base is arranged in connection with a coil and a change in inductance, correlating with the content of the magnetically marked analyte, is detected.

Abstract: A method and apparatus for the manipulation of colloidal particulates and biomolecules at the interface between an insulating electrode such as silicon oxide and an electrolyte solution. Light-controlled electrokinetic assembly of particles near surfaces relies on the combination of three functional elements: the AC electric field-induced assembly of planar aggregates; the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The present invention provides a set of fundamental operations enabling interactive control over the creation and placement of planar arrays of several types of particles and biomolecules and the manipulation of array shape and size. The present invention enables sample preparation and handling for diagnostic assays and biochemical analysis in an array format, and the functional integration of these operations.

Abstract: Novel magnetic assay methods and systems. According to a preferred embodiment, a chromatographic medium, which preferably comprises a test strip, is provided that is designed to be contacted with a test solution having activated magnetic particles such that the solution flows bilaterally thereacross. A magnetic field, generated by a magnet or electromagnet, is selectively applied to the medium which causes the charged particles to become substantially bound at a site on the medium specified by the position of the magnet, to thus form a captured line or zone. In one preferred embodiment, the magnetic field is applied at the site on the medium at which the test solution is contacted. The degree of magnetic force applied to the membrane may be selectively adjusted to vary the width or surface area of the capture line or zone.

Abstract: The invention relates to a new process for detecting analytes or binding reactions using measurement of the double refraction, as well as the use of the compounds in analytical chemistry that are necessary for this purpose.

Abstract: When insoluble magnetic carrier particles are used in immunoassay, a method is provided which is suitable for saving labor and for treating a large number of samples within a short time while avoiding problems including difficulties in the stability of sensitized insoluble magnetic particles and in their preparation. In assaying an antigenic substance in test samples, no use is made of insoluble magnetic particles carrying an antibody specific to the said antigenic substance but insoluble magnetic carrier particles are provided in a state free from adsorbing said antibody, etc. Then the antigenic substance per se to be assayed is adsorbed on the insoluble magnetic carrier particles followed by reaction with a labeled antibody specific to the said adsorbed antigenic substance. Thus, the antigenic substance in the test sample can be efficiently assayed in a mode suitable for automation.

Abstract: Heterogeneous assays for different analytes in a single biological sample are performed simultaneously in a multiplexed assay that combines flow cytometry with the use of magnetic particles as the solid phase and yields an individual result for each analyte. The particles are distinguishable from each other by characteristics that permit them to be differentiated into groups, each group carrying an assay reagent bonded to the particle surface that is distinct from the assay reagents of particles in other groups. The magnetic particles facilitate separation of the solid and liquid phases, permitting the assays to be performed by automated equipment. Assays are also disclosed for the simultaneous detection of antibodies of different classes and a common antigen specificity or of a common class and different antigen specificities.

Abstract: A method and apparatus for the manipulation of colloidal particulates and biomolecules at the interface between an insulating electrode such as silicon oxide and an electrolyte solution. Light-controlled elektrokinetic assembly of particles near surfaces relies on the combination of three functional elements, the AC electric field-induced assembly of planar aggregates; the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The present invention provides a set of fundamental operations enabling interactive control over the creation and placement of planar arrays of several types of particles and biomolecules and the manipulation of array shape and size. The present invention enables sample preparation and handling for diagnostic assays and biochemical analysis in an array format, and the functional integration of these operations.

Abstract: The invention relates to a method for separating out a substance dispersed or dissolved in a first liquid by using the following steps: a) adding magnetizable particles to the first liquid, so that the substance is adsorbed on the particles; b) immersing a rod consisting of a soft magnetic material into the first liquid; c) magnetizing the rod along its longitudinal axis with an exciter coil, thus causing the particles with the adsorbed substance to be deposited on the rod; d) pulling the rod with thereon deposited particles from the first liquid while the rod is still magnetized; e) immersing the rod into a second liquid; f) turning off the exciter coil and washing off the particles deposited on the rod in the second liquid. Also proposed is a magnet separator for realizing the method.

Abstract: An apparatus is provided for quantitatively measuring samples whose amount or other characteristic quality is to be determined. The samples are arranged in a predefined pattern and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one substantially flat sensor such as sensing coils fabricated in a gradiometer configuration.

Abstract: Disclosed are silica-coated nanoparticles and a process for producing silica-coated nanoparticles. Silica-coated nanoparticles are prepared by precipitating nano-sized cores from reagents dissolved in the aqueous compartment of a water-in-oil microemulsion. A reactive silicate is added to coat the cores with silica. Also disclosed are methods for functionalizing silica-coated nanoparticles for use in a variety of applications.

Abstract: In accordance with the present invention, it has been discovered that introduction of hydrophilic sulfoalkyl substituents and/or hydrophilic linkers derived from homocysteic acid, cysteic acid, glycine peptides, tetraethylene oxide, and the like, offset the hydrophobicity of the acridinium ring system to produce a more soluble label which can be attached to an antibody at higher loading before precipitation and aggregation problems are encountered. Additional compounds described herein contain linkers derived from short peptides and tetraethylene oxide which increase aqueous solubility due to hydrogen bonding with water molecules. The present invention also embraces reagents for multiple acridinium labeling for signal amplification composed of a peptide bearing several acridinium esters with sulfonate groups at regularly spaced intervals for increased solubility. The invention also embraces assays employing the above-described compounds.

Abstract: A novel compound comprising an immunologically invisible polyethylene glycol copolymer is used to carry one or more immunologically reactive substances. The novel compounds may be used as part of kits for immunological assays.

Abstract: This invention relates to preservative solutions for peptides, for example, parathyroid hormone, insulin-like growth factor binding protein 3 (IGFBP3), adrenocorticotropic hormone (ACTH) and mixtures thereof. Preferably, the peptides preserved by the solutions are non-reconstituted. In one embodiment, the preservative solutions comprise a polyvinyl alcohol, EDTA component and molybdic component.

Abstract: The present invention relates generally to methods for stimulating cells, and more particularly, to a novel method to concentrate and stimulate cells that maximizes stimulation and/or proliferation of such cells. In the various embodiments, cells are stimulated and concentrated with a surface yielding enhanced proliferation, cell signal transduction, and/or cell surface moiety aggregation. In certain aspects methods for stimulating a population of cells such as T-cells, by simultaneous concentration and cell surface moiety ligation are provided by contacting the population of cells with a surface, that has attached thereto one or more agents that ligate a cell surface moiety and applying a force that predominantly drives cell concentration and cell surface moiety ligation, thereby inducing cell stimulation, cell surface moiety aggregation, and/or receptor signaling enhancement.

Abstract: The invention relates to a method for detecting specific target-cells in a simple and time saving way, using paramagnetic particles, antibodies recognizing the Fc portions of target-cell associating antibodies and target-cell associating antibodies directed to specific antigen determinants in the target-cell membranes. Incubation of the cell suspension with a mild detergent and/or second set of antibodies or antibody fragments, prelabeled or not with fluorescent agents, metallocolloids, radioisotopes, biotincomplexes or certain enzymes allowing visualization, with dramatically increase the specificity of the method. The method can further be used for isolation of the target-cells by magnetic field application and kit for performing the method according to the invention is described.

Abstract: Apparatuses and methods for separating, immobilizing, and quantifying biological substances from within a fluid medium. Biological substances are observed by employing a vessel (6) having a chamber therein, the vessel comprising a transparent collection wall (5). A high internal gradient magnetic capture structure may be on the transparent collection wall (5), magnets (3) create an externally-applied force for transporting magnetically responsive material toward the transparent collection wall (5). The magnetic capture structure comprises a plurality of ferromagnetic members and has a uniform or non-uniform spacing between adjacent members. There may be electrical conductor means supported on the transparent collection wall (5) for enabling electrical manipulation of the biological substances. The chamber has one compartment or a plurality of compartments with differing heights. The chamber may include a porous wall.

Abstract: The present invention relates to equine Fc epsilon receptor alpha chain nucleic acid molecules, proteins encoded by such nucleic acid molecules, antibodies raised against such proteins, and inhibitors of such proteins. The present invention also includes methods to detect IgE using such proteins and antibodies. Also included in the present invention are therapeutic compositions comprising such proteins, nucleic acid molecules, antibodies and/or inhibitory compounds as well as the use of such therapeutic compositions to mediate Fc epsilon receptor-mediated biological responses.

Abstract: A ferromagnetic thin-film based magnetic field detection system used for detecting the presence of selected molecular species. A magnetic field sensor supported on a substrate has a binding molecule layer positioned on a side thereof capable of selectively binding to the selected molecular species. The magnetic field sensor can be substantially covered by an electrical insulating layer having a recess therein adjacent to the sensor in which the binding molecule layer is provided. An electrical interconnection conductor can be supported on the substrate at least in part between the sensor and the substrate, and is electrically connected to the sensor. The magnetic field sensor can be provided in a bridge circuit, and can be formed by a number of interconnected individual sensors. A polymeric channel and reservoir structure base is provided for the system.

Abstract: The invention provides immunological reagents (antibodies) capable of binding to plasmacytoid dendritic cells (pDC), to cell lines which express such antibodies and to a process for identifying and purifying plasmacytoid dendriticcells from tissues containing pDC using such antibodies.

Abstract: Heterogeneous assays for different analytes in a single biological sample are performed simultaneously in a multiplexed assay that combines flow cytometry with the use of magnetic particles as the solid phase and yields an individual result for each analyte. The particles are distinguishable from each other by characteristics that permit them to be differentiated into groups, each group carrying an assay reagent bonded to the particle surface that is distinct from the assay reagents of particles in other groups. The magnetic particles facilitate separation of the solid and liquid phases, permitting the assays to be performed by automated equipment. Assays are also disclosed for the simultaneous detection of antibodies of different classes and a common antigen specificity or of a common class and different antigen specificities.

Abstract: Disclosed is apparatus and method for controlled surface plasmon resonance analysis having a surface plasmon resonance sensor (200) with a derivatized surface plasmon layer (116) in optical communication with the sensor, derivatizing the surface plasmon layer and placing an analyte detection chamber (102) in fluid communication with the derivatized surface plasmon layer. The chamber is adapted (118, 120) for the generation of a molecular interaction bias across the chamber. A conjugate is provided between an analyte and a bias responsive element, wherein the analyte is reactive with the derivatized surface plasmon layer and the bias responsive element changes the response of the analyte to the molecular interaction bias. A conjugated analyte may be introduced into the chamber, generating a molecular interaction.

Abstract: Magnetic particles are prepared containing a magnetic core coated with a glass layer having a substantially pore-free class surface or having pores with a diameter offices than 10 nm. The particles are used for separating biological material such as nucleic acids. A preferred process of preparing the particles is by forming a mixture of magnetic cores with a sol formed from an alcohol and a metal alkoxide, spray-drying the mixture to coat the cores with a layer of gelled sol, and heating the coated cores to obtain the magnetic glass particles. Preferably, the particles have an average particle size of less than 100 ?m. The magnetic core may be a composite material containing a mica core and magnetite particles immobilized on the mica core, and the glass layer may contain boron oxide. Magnetic core materials include magnetite (Fe3O4) and Fe2O3.

Abstract: The present invention relates generally to methods for stimulating cells, and more particularly, to a novel method to concentrate and/or stimulate cells that maximizes stimulation and/or proliferation of such cells. In the various embodiments, cells are stimulated and concentrated with a surface yielding enhanced proliferation, cell signal transduction, and/or cell surface moiety aggregation. In certain aspects methods for stimulating a population of cells such as T-cells, by simultaneous concentration and cell surface moiety ligation are provided by contacting the population of cells with a surface, that has attached thereto one or more agents that ligate a cell surface moiety and applying a force that predominantly drives cell concentration and cell surface moiety ligation, thereby inducing cell stimulation, cell surface moiety aggregation, and/or receptor signaling enhancement.

Abstract: A waveguide probe for the detection of pathogens in a sample which comprises a laser, a first and a second tubes that converge at a point to form a proximal end. A magnet is positioned in the end to configure to focus paramagnetic microspheres attached to antigen/antibody/optically labeled antibody complexes in the field of view. The proximal end is polished to form an aperture.

Abstract: Disclosed herein are apparatuses and devices, and methods for using and making the same, for use in performing desired activities in an automated, microscale format. Microparticles are ushered about within a microscale apparatus, to selectively move between various stations in a selected order and manner. Some embodiments include reaction, micro-weighing, micro-analysis, reagent acquisition and deposition, and incubation stations. Microparticles can individually move, or move as trains. Samples, including particulate and solid tissue samples may be manipulated and analyzed within the device. Some embodiments may engage in micro-fabrication activities or micro-deconstruction activities. Systems for controlling such apparatuses are included as well as methods of operation.

Abstract: A method for measuring low levels of a substance in a sample includes the formation of a rotor from paramagnetic particles in a substantially uniform magnetic field. The rotor is rotated by rotating the substantially uniform magnetic field. A portion of the substance in a sample is bound to the paramagnetic particles, and a signal having a time-varying component is detected. The signal is then processed using a lock-in amplifier with a reference signal having a frequency twice that of the rotation of the magnetic field. This improves the signal-to-noise ratio of the time-varying component of the signal.

Abstract: A magnetic sensing element detects the presence of magnetic particles in a binding assay. The magnetic sensing element has at least one planar layer of electrically conductive ferromagnetic material that has an initial state in which the material has a circular magnetic moment within the plane of the layer. The magnetic sensing element has molecules of a first specific binding member attached to it. The device also includes a fluid test medium to which the magnetic sensing element is exposed during the course of a binding assay. The fluid test medium includes magnetizable particles that become immobilized during the assay in relation to the amount of analyte in the test medium.

Abstract: A method and kit for monitoring autoantibodies to thyroid stimulating hormone (TSH) receptor in a sample of body fluid, which employs the steps of: (i) incubating TSH receptor with a sample of body fluid; (ii) reacting the incubated sample of body fluid with at least one binding agent which is capable of binding to the TSH receptor in competitive reaction with TSH receptor autoantibodies (TRAb), or in a case where TSH receptor is complexed to labelled antibody, reacting the sample of body fluid with at least one binding agent which can bind to TRAb in such a way as not substantially to interfere with binding of the TRAb to the TSH receptor; and (iii) detecting bound TRAb in the reacted incubated sample of body fluid.