Abstract: Magnetically labeled cells in a flow chamber cytometer are detected by a GMR sensor. The flow chamber includes a cell guiding device having at least one first and one second magnetic or magnetizable flow strip. The flow strips, which serve to guide the flowing cells across the sensor in a target-oriented manner, are mounted at a distance from each other such that a magnetic field BF is produced between them. The GMR sensor is arranged in the region of the magnetic field BF between the flow strips such that the magnetic field BF can be used as the operating magnetic field BGMR of the GMR sensor. In this way, the need for additional magnets for operating the GMR sensor is eliminated.

Abstract: In one embodiment, a device for measuring concentration of a paramagnetic gas is provided. The device comprises a measuring cell having a closed cavity therein, a reference gas conduit extending into the cavity for supplying a reference gas to the measuring cell, the reference gas comprising a predetermined concentration of the paramagnetic gas, a measurable gas conduit extending into the cavity for supplying a measurable gas to the measuring cell, the measurable gas comprising a measurable concentration of the paramagnetic gas, a first microphone differentially coupled to the measurable gas conduit and the reference gas conduit, and a second microphone located at a predetermined distance from the reference gas conduit.

Abstract: The invention relates to a method and an apparatus (100) for the enrichment of magnetic particles (1) in a sample fluid. The sample fluid is provided in a sample cartridge (2) between a first pole (111) and a second pole (112) of an actuator magnet (110). A minimal magnetic flux as well as a minimal magnetic gradient are then established inside the sample fluid, wherein their values depend on the particular magnetic particles (1) and the sample fluid under consideration. In a preferred embodiment, the first pole (111) has a single tip (T).

Abstract: An apparatus and a method for inspecting use a sensor for detecting taggant particles in a material after installation. The sensor is positioned adjacent a finished surface of the installed material and is connected to a control device for displaying an indication of a distribution of the taggant particles below the surface. The control device also generates a profile of the taggant particles versus a distance from the surface.

Abstract: Disclosed is an apparatus for measuring ac magnetization at mixture frequency. The apparatus includes an ac generating unit for generating at least a first current with a frequency f1 and a second current with a frequency f2. The apparatus further includes a co-axial solenoid unit, driven by the first and second ac currents, to generate a first magnetic field and a second magnetic field. A pick-up solenoid is for disposing sample for detecting an ac magnetization of the sample and multiple frequency-component signals corresponding to various frequency combinations of f1 and f2 are output. The apparatus further includes a signal processing circuit for receiving the frequency-component signals, where the signal processing circuit obtains the ac magnetization of the sample at a target frequency of (?Tf1+?Tf2), which ?T and ?T are positive integers and the frequency f1 and the frequency f2 are two different frequencies.

Abstract: A sensor device for detecting one or more magnetic particles (102) in a sample fluid is described. The sensor device (100) uses at least one rotating magnetic field generator (108) for applying a rotating magnetic field to the sample and more particularly the one or more magnetic particles (102) incorporated therein. The sensor device also comprises a controller for controlling the magnetic field generator such that the rotating frequency of the applied magnetic field is substantially larger than the critical slipping frequency for the magnetic particle. The effect of the induced rotation is sensed using a sensor element (112). Presence, amount and binding properties of the magnetic particles (102) may be derived from the measured effect. Alternatively or additionally the viscosity of the sample fluid may be determined.

Abstract: A method for identifying capsules in a beverage producing device by providing a capsule comprising at least one identifier attached thereto or embedded therein; the identifier comprising a magnetically-responsive material, providing detecting means in the beverage producing device to detect the identifier including at least one emitting coil and at least one receiving coil, positioning the identifier in the magnetic field thereby altering the magnetic signal resulting therefrom, emitting a magnetic signal from the at least one emitting coil, detecting an altered signal by the receiving coil and identifying the capsule according to the alteration provided to the magnetic signal.

Abstract: A graphite-based sensor includes an undoped graphite structure that adsorbs foreign atoms and molecules. A magnetization detection device includes a substrate on which the graphite structure is adhered, a current source by which a current is applied to the substrate and the graphite structure, and a voltage measuring device coupled to the substrate. When the graphite structure adsorbs the gas molecules, the graphite structure exhibits a ferromagnetic-type behavior, and a corresponding voltage generated in the magnetic detection device changes.

Abstract: A sensor array comprising a series connection of parallel GMR sensor stripes provides a sensitive mechanism for detecting the presence of magnetized particles bonded to biological molecules that are affixed to a substrate. The adverse effect of hysteresis on the maintenance of a stable bias point for the magnetic moment of the sensor free layer is eliminated by a combination of biasing the sensor along its longitudinal direction rather than the usual transverse direction and by using the overcoat stress and magnetostriction of magnetic layers to create a compensatory transverse magnetic anisotropy. By making the spaces between the stripes narrower than the dimension of the magnetized particle and by making the width of the stripes equal to the dimension of the particle, the sensitivity of the sensor array is enhanced.

Abstract: A device for measuring a concentration of magnetic material has exciting coils 11a and an output coil 11b which generates exciting voltage when alternating current flows through the exciting coils 11a. Measurement means 6 is provided to measure variation in phase difference between voltages of the exciting and output coils 11a and 11b, so that a concentration of magnetic material is measured with high accuracy from variation in phase difference when a test object is caused to approach the exciting coil 11a or/and the output coil 11b. A minute concentration of magnetic material in the fluid is continuously measured.

Abstract: Magnetic and counterpart members 12 and 11 are immersed in a liquid which may include hard particles. At least one of the members 12 and 11 is moved while pressed to the other member. The magnetic member 12 is worn by hard particles in the liquid to produce magnetic particles in the liquid. A concentration of the magnetic particles produced is measured and is converted into a concentration of hard particles in the liquid on the basis of a calibration line representing a correlation measured in advance between the concentrations of the magnetic particles and of the hard particles in the liquid. Thus, the concentration of the hard particles in the liquid is detected.

Abstract: A system for measuring the concentration of magnetic ballast in a moving slurry including a detection conduit surrounded by a set of coaxial detection coils configured to receive the moving slurry, a reference conduit surrounded by a set of coaxial coils, an AC power source for establishing a magnetic field in one of the detection coils and one of the reference coils, and a measurement subsystem for measuring the differential induced voltage between one of the set of coaxial detection coils and one of the set of coaxial reference coils to determine the concentration of the magnetic ballast in the moving slurry.

Abstract: The aim of the invention is to model the gravitational field-induced or centrifugal field-induced separation of particles of a dispersion by means of one or more additional force fields that also influence the migration of the particles. Said aim is achieved by detecting and measuring the modified separation behavior with the help of concentration-measuring sensors. The force acting upon the particles can be calculated from the change in velocity of the particles, and the corresponding particle properties can be calculated if the respective field intensities are known.

Abstract: An apparatus and a method for monitoring a ratio of at least two components being mixed use sensors detecting ferrous taggant particles in the component(s) and the mixture. The sensors include an annular drive coil positioned between inner and outer annular sense coils all surrounding a passage for material being sensed. The ratio is determined by comparing a signal generated by one sensor through which a taggant particle containing component is flowing with a signal generated by another sensor through which the mixture is flowing delayed by the time required for the component to flow from the one sensor to the another sensor. The signals can also be used to control the flow of the components and to check the mixture after use for such mixtures as asphalt and concrete.

Abstract: A detection unit 4 with detection means 3 and fluid inflow/outflow guide means 2 is connected to a passage 1 for fluid with conductive material or to a pool section 5 for pooling of the fluid. The detection unit 4 guides inflow and outflow of the fluid through the fluid inflow/outflow guide means 2 and detects a concentration of conductive material through the detection means 4. A concentration of conductive material in the fluid is continuously measured with high accuracy.

Abstract: To provide a broken piece detecting sensor assembly capable of stably detecting broken piece admixed in a fluid, which broken piece is made of material characterized by non-metal, non-magnetic and non-electroconductive characteristics such as ceramics. This broken piece detecting sensor assembly is a sensor for detecting broken piece admixed in a fluid. Provided are two opposed flat plates, a shift mechanism for moving at least one of the two flat plates in a confronting direction to allow the broken piece to be sandwiched between those two flat plates, and measuring and determining section. The measuring and determining section is operable to measure the distance between the two flat plates to thereby detect the presence or absence of the broken piece, the size of the broken piece or the amount of the broken piece accumulated.

Abstract: With an offset circuit including transistors of the same conductivity type, offset of an input signal is performed. Then, the input signal after the offset is supplied to a logic circuit including transistors of the same conductivity type as that of the offset circuit, thereby H and L levels of the input signal can be shifted at the same time. Further, since the offset circuit and the logic circuit are formed using the transistors of the same conductivity type, a display device can be manufactured at a low cost.

Abstract: A process and device for detecting electrically conductive particles in a liquid flowing in a pipe section, the liquid being exposed to periodic alternating electromagnetic fields by a transmitter coil which induces eddy currents in the particles, a probe made as a coil arrangement and which has an effective width producing a periodic electrical signal based on the eddy currents. The signal ha a carrier oscillation with an amplitude and/or phase which is modulated by particles passing across the effective width of the coil arrangement, the probe signal being filtered by a frequency-selective first filter unit, the filtered signal being sampled by a triggerable A/D converter stage to obtain a demodulated digital measurement signal, the digital measurement signal being filtered by a digital, frequency-selective adjustable second filter unit to obtain a useful signal, and the useful signal being evaluated to detect passage of electrically conductive particles in the pipe section.

Abstract: An apparatus and a method for monitoring a ratio of at least two components being mixed use sensors detecting ferrous taggant particles in the component(s) and the mixture. The sensors include an annular drive coil positioned between inner and outer annular sense coils all surrounding a passage for material being sensed. The ratio is determined by comparing a signal generated by one sensor through which a taggant particle containing component is flowing with a signal generated by another sensor through which the mixture is flowing delayed by the time required for the component to flow from the one sensor to the another sensor. The signals can also be used to control the flow of the components and to check the mixture after use.

Abstract: A system for determining magnetic permeability of a material. Two electrical inductors formed as primary and secondary concentric coils share a common magnetic core space. A first AC voltage applied to the primary coil creates a magnetic flux in the core proportional to the magnetic permeability of the material. The magnetic flux induces an AC voltage in the secondary coil indicative of the apparent magnetic permeability of the sample. The apparent permeability is corrected for conductivity by imposing a second AC voltage and resistor in series across first and second electrodes disposed in the material. When the material is a magnetorheological fluid, the magnetic permeability is proportional to the concentration of magnetic particles in the sample and can be back-calculated from the amplitude of the secondary voltage signal.

Abstract: A method and apparatus for removing soluble and insoluble contaminants from highly purified and ultra-pure liquids having a bulk resistivity in excess of one megohm-centimeter by establishing laminar flow of the liquid in a cylindrical chamber through an electromagnetic field transverse to the direction of flow, to induce mobility of the constituents. The wall of the chamber forms a cathode and a central rod forms an anode in the chamber. The mobilized constituents are transported either to the anode or the cathode, where the material will adhere and agglomerate with other constituents. Systems are provided utilizing the method and apparatus for purifying and analytically evaluating highly purified and ultra-pure water.

Abstract: The present invention provides a sensor cartridge (10) for distinctively determining at least two different target moieties in a fluid sample. The sensor cartridge (10) comprises a reaction chamber (1) and at least a first and second region (2, 3) distinct from each other. The first region (2) comprises magnetic or magnetizable objects (4a) labelled with a first type of probes for specifically binding a first type of target moieties and the second region (3) comprises magnetic or magnetizable objects (4b) labelled with a second type of probes for specifically binding a second type of target moieties, the magnetic or magnetizable objects (4a, 4b) in the first and second region (2, 3) being directly contactable by the sample fluid. The present invention also provides a method for the manufacturing of such sensor devices (10) and a method for determining the presence and/or amount of at least two different target moieties in a sample fluid using such sensor cartridge (10).

Abstract: A magnetic sensor device (20) for determining the presence and/or amount of target moieties in a sample fluid is provided. The magnetic sensor device comprises:—a sensor chamber (12) having a sensor surface (120), the sensor surface comprising a plurality of binding sites (121) adapted for binding magnetic or magnetizable objects; and—a magnetic field generating means (26) adapted for generating a magnetic field for inducing a movement of magnetic or magnetizable objects along the sensor surface (120), the magnetic fields having a magnetic field gradient across the sensor surface (120). The magnetic field gradient generated by the magnetic field generating means (26) in each of the centres of the plurality of binding sites (121) is substantially identical.

Abstract: Detecting magnetized or magnetizable target components in a fluid containing the magnetized or magnetizable target components amongst other magnetized or magnetizable components, uses a magnetic field generator (M1, 28) to attract the magnetized or magnetizable components towards a binding surface. A magnetic field controller (C1) applies the magnetic field to concentrate the magnetized or magnetizable components in columns on the binding surface, subsequently reduces the magnetic field to enable the columns to collapse, to allow more components to reach the binding surface, and reapplies the magnetic field so as to cause other components to be pulled off the binding surface to reform columns based on the bound target components. A surface sensitive sensor (S1, 26, 29) detects the bound magnetized or magnetizable target components.

Abstract: Disclosed is a method of analysis of a mixture of biological and/or chemical components that entails spatially arranging a chosen component attached to magnetic particles, exposing the particles to a magnetic field, and recording a magnetic induction signal, from which the content of the analyte in the mixture is judged; this includes grouping the chosen component in a probe volume, making the magnetic field alternating, pre-setting its spectrum, at least, at two frequencies, and recording the signal at a frequency, which is a linear combination of these frequencies, during the exposure of the magnetic particles to the field.

Abstract: Method of quantifying an analyte in a liquid medium by means of magnetic particles functionalized by specific ligands of the analyte being quantified, consisting in applying a magnetic field to a liquid medium for a time period several times shorter than that of the reaction between the analyte being quantified and the ligands of the magnetic particles, in measuring the optical density of the liquid medium after applying the magnetic field, in repeating this cycle of applying the magnetic field and of measuring the optical density several times over the duration of the reaction between the analyte and the ligands, in calculating, by extrapolation, a limiting value for the optical density for an infinite magnetic field application time and in deducing therefrom the concentration of the analyte in the liquid medium.

Abstract: The aim of the invention is to model the gravitational field-induced or centrifugal field-induced separation of particles of a dispersion by means of one or more additional force fields that also influence the migration of the particles. Said aim is achieved by detecting and measuring the modified separation behavior with the help of concentration-measuring sensors. The force acting upon the particles can be calculated from the change in velocity of the particles, and the corresponding particle properties can be calculated if the respective field intensities are known.

Abstract: The invention relates to a magnet system for biosensors. To achieve a magnetic system, which can switch between attraction force and repulsion force, near the sensor surface, the magnetic system has at least one coil (1) and a ferromagnetic open ring system (3), where both magnetic pole faces are adjacent to each other over a gap (4) in which the biosensor is located, and where the coil (1) or the ferromagnetic core (2) in the coil, or an inner part of the ferromagnetic core in relation to each other are shiftable, in order to change the magnetic force direction near the biosensor surface.

Abstract: The invention concerns a gas analyzer, which comprises: an electromagnet that has an air gap; a power source for supplying cyclically variable electrical current/voltage to said electromagnet; a sample gas conduit and a reference gas conduit opening into said air gap; an exit conduit communicating with said air gap for removing the intermixed sample and reference gases; pressure detecting microphone or microphones connected to said sample gas conduit and to said reference gas conduit for sensing gas pressures at a first acoustic measuring frequency in the respective conduits giving at least one acoustic pressure signal component; and electronics connected to said microphone(s) to receive said acoustic pressure signal component or components to form at least a first intermediate output signal describing content of a paramagnetic gas component in the sample gas.

Abstract: A fluid production computation apparatus using the electromagnetic induction theory is disclosed. In accordance with an embodiment of the present invention, the fluid production computation apparatus includes a line through which a current flows according to fluid production; a magnetic sensor, measuring magnetism induced by the current; and a fluid production computation unit, computing the fluid production through magnetism measured by the magnetic sensor. The conventional flow measurement apparatus measures the flow by measuring a current or a voltage induced by magnetism formed by a fluid or by using a fluid measurement sensor. However, with the present invention, an apparatus can be miniaturized and the measurement can be precisely performed by measuring a magnetic field induced by a current flowing according to fluid production.

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flowpaths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof.

Abstract: A device for detecting parts in a material flow which influence an electromagnetic alternating field comprises an oscillator (1) and at least one transmitting coil (2) for generating an electromagnetic alternating field extending across the width of a conveying distance of the material flow. At least one detector coil (4) comprising two windings (4a, 4b) connected inversely detects the electromagnetic alternating field and generates a detection signal (DS), the phase signal portion (PS?) of which is detected by means (7), from the relative motion between the alternating field and a field-influencing part.

Abstract: Disclosed is a method of analysis of a mixture of biological and/or chemical components that entails spatially arranging a chosen component attached to magnetic particles, exposing the particles to a magnetic field, and recording a magnetic induction signal, from which the content of the analyte in the mixture is judged; this includes grouping the chosen component in a probe volume, making the magnetic field alternating, pre-setting its spectrum, at least, at two frequencies, and recording the signal at a frequency, which is a linear combination of these frequencies, during the exposure of the magnetic particles to the field.

Abstract: A sensor device (50) for sensing particles (15) of a sample, the sensor device (50) comprising a sensing unit (11, 20) adapted for sensing a detection signal indicative of the presence of the particles (15), a viscosity measurement unit (11, 17, 20) adapted for measuring the viscosity of the sample, and a correction unit (20, 30) adapted for correcting the detection signal based on the measured viscosity.

Abstract: Methods and systems for multiforce high throughput screening are disclosed. According to one aspect, the subject matter includes a high throughput screening system that includes a multiforce plate having a plurality of field forming poles where each field forming pole is positioned on the multiforce plate at a location corresponding to a well in a multiwell plate. The system also includes an exciter assembly with excitation poles positioned at locations corresponding to the field forming poles. The excitation poles are utilized for electrically or magnetically coupling to the field forming poles and for delivering at least one of an electric and magnetic field in the vicinity of the field forming poles. The coupled field forming poles apply force via the field(s) to probes located in the wells of the multiforce plate in order to move the probes and test mechanical properties of specimens in the wells.

Abstract: A method and an arrangement for influencing and/or detecting magnetic particles in a region of action of an examination object is disclosed, which method comprises the steps of: generating a magnetic selection field by means of selection means, the magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength and a second sub-zone having a higher magnetic field strength are formed in the region of action, changing the position in space of the two sub-zones in the region of action by means of a magnetic drive field generated by drive means so that the magnetization of the magnetic particles change locally, acquiring signals by means of receiving means, which signals depend on the magnetization in the region of action, which magnetization is influenced by the change in the position in space of the first and second sub-zone, wherein the selection means and/or the drive means and/or the receiving means are provided at least partly

Abstract: The invention relates to a sensor device, particularly a magnetic sensor device (200), for detecting magnetic particles (2) in a sensitive region (202) of a sample chamber (201). Magnetic particles (1) can be moved with the help of magnetic forces from the sensitive region (202) into a dump region (203), which is arranged such that the magnetic particles (1) cannot return to the sensitive region (202) by pure sedimentation. The separation between the sensitive and the dump region can optionally be enforced by a barrier (204).

Abstract: A detection system (100) is described for detecting analytes in a fluid sample. The detection system (100) comprises a transporting means (6) for transporting magnetic and/or electric labels (5) after interaction between the sample fluid and the reagents towards a detection receptacle (1). The detection receptacle (1) is initially substantially magnetic and/or electric label (5) free. By transporting the magnetic and/or electric labels (5) after reaction, interference between unreacted reagents and magnetic and/or electric label-assisted detection can be reduced.

Abstract: A system and a method for monitoring a building material are disclosed. The system and the method provide a comprehensive monitoring throughout a manufacturing and an application process and provide a real time data feedback relating to the physical characteristics of the building material. The system and method include mixing a predetermined amount of taggant particles with a predetermined volume of at least one component of the building material in order to comprehensively monitor a mix ratio and segregation of the building material during manufacturing and application.

Abstract: Determination of at least one of physical, chemical and biological properties and parameters within an area of examination of an object of examination by introducing magnetic particles in at least a portion of the area of examination, generating a magnetic field with a spatial distribution of the magnetic field strength such that the area of examination includes a first sub-area with lower magnetic field strength and a second sub-area with a higher magnetic field strength, changing the spatial location of both sub-areas in the area of examination so that the magnetization of the particles changes locally, acquiring signals that depend on the magnetization in the area of examination influenced by the changing of the spatial location of both sub-areas, and evaluating the signals to obtain information about the anisotropy of the magnetic particles in the area of examination.

Abstract: Sensor for determining the electrical conductivity of liquid media comprising a multilayer layered structure (1), with a carrier substrate with two wound (3b, 4b) magnetizable cores (3a, 4a) and a dielectric coating. The invention also comprises a method in which a greenbody for a magnetizable core with metallic windings is applied onto a dielectric ceramic base green film, and a second magnetizable core with metallic windings is applied and subsequently a coating is applied before or after the sintering. The invention further comprises a method in which magnetizable cores with metallic windings are applied onto a dielectric organic base plate or base film.

Abstract: A ferromagnetic thin-film based magnetic field detection system having a substrate supporting a magnetic field sensor in a channel with a first electrical conductor supported on the substrate positioned at least in part along the channel gap and in direct contact with at least some surface of the magnetic field sensor ands a second electrical conductor supported on the substrate positioned at least in part along the channel gap in a region thereof adjacent to, but separated from, the magnetic field sensor.

Abstract: The invention relates to a method and a magnetic sensor device for the determination of the concentration of target particles (2) in a sample fluid, wherein the amount of the target particles (2) in a sensitive region (14) is observed by sampling measurement signals with associated sensor units (10a-10d). The target particles (2) may optionally be bound to binding sites (3) in the sensitive region, and a parametric binding curve, e.g. a Langmuir isotherm, may be fitted to the sampled measurement signals to determine the desired particle concentration in the sample. Moreover, parameters like the sampling rate and the size of the sensitive region (14) can be dynamically fitted during the ongoing sampling process to improve the signal-to-noise ratio. In another embodiment of the invention, single events corresponding to the movement of target particles into, out of, or within the sensitive region are detected and counted.

Abstract: The present invention relates to an excitation and measurement method for a magnetic biosensor. Using at least a digital magnetic sensor element (100) a magnetic bead (110) is magnetized such that a magnetic stray field of the magnetic bead (110) prevents switching of a magnetic element (108) of the at least a digital magnetic sensor element (100) when the magnetic bead (110) is in close proximity to the top surface of the at least a digital magnetic sensor element (100). Measuring of the state of the magnetic element (108) allows the determination of a presence or non-presence of a magnetic bead (110). The method is highly advantageous by employing MRAM technology in biosensor systems.

Abstract: A device for measuring a concentration of magnetic material has exciting coils 11a and an output coil 11b which generates exciting voltage when alternating current flows through the exciting coils 11a. Measurement means 6 is provided to measure variation in phase difference between voltages of the exciting and output coils 11a and 11b, so that a concentration of magnetic material is measured with high accuracy from variation in phase difference when a test object is caused to approach the exciting coil 11a or/and the output coil 11b. A minute concentration of magnetic material in the fluid is continuously measured.

Abstract: A system for determining the magnetic permeability of a material is provided. Two electrical inductors formed as primary and secondary concentric coils share a common magnetic core space. An AC voltage applied to the primary coil creates a magnetic flux in the core proportional to the magnetic permeability of a sample of the material positioned within the core space. The magnetic flux induces an AC voltage in the secondary coil indicative of the sample magnetic permeability. When the material is a magnetorheological fluid, the magnetic permeability is proportional to the concentration of magnetic particles in the sample and can be back-calculated from the amplitude of the secondary voltage signal. Sensitivity and resolution can be increased by using two identical sets of coils wherein a reference material forms a core for the primary set and the MR fluid sample forms a core for the secondary set.

Abstract: A magnetic sensor has a needle-shaped detecting part. The needle-shaped detecting part includes a substrate cut to have a needle shape, at least one MR element formed on the substrate, at least two lead conductors formed on the substrate, one end of the conductor being electrically connected to at least one MR element, and a protection film covering the at least one MR element and the at least two lead conductors.

Abstract: A method to quantitatively measure an amount of bio-molecules in a sample includes providing a solution having magnetic nanoparticles; coating bioprobe molecules to surfaces of the magnetic nanoparticles in the solution; measuring a first alternating current (ac) magnetization of the solution at a mixture frequency (?f1+?f2), wherein ? or ? is independently an integer larger than zero; adding a sample containing the bio-molecules to be detected to the solution, so that the biomolecules in the sample conjugate with the bioprobe molecules coated on the nanoparticles; and measuring a second ac magnetization of the solution at the mixture frequency (?f1+?f2) after adding the sample and incubation, so as to obtain an ac magnetization reduction at the mixture frequency (?f1+?f2) between the first and the second magnetization to determine the amount of the bio-molecules.

Abstract: The present invention relates to method and device for detecting changes of a magnetic response of at least one magnetic particle in a carrier fluid. The method comprises: using a measuring procedure comprising measuring the characteristic rotation time of said magnetic particle, said measuring procedure further involving measuring Brownian relaxation in said carrier fluid under influence of an external pulsed excitation magnetic field, and based on said influence of said external pulsed excitation magnetic field measuring a hydrodynamic volume of a particle or a change in a hydrodynamic volume of the particle change upon modification of an effective volume of the particle or its interaction with said carrier fluid by detecting change of magnetization of the particle with time by monitoring change of an output signal in detection coil.

Abstract: The invention relates to a magnetic sensor device comprising excitation wires (11, 13) for generating a magnetic excitation field and a magnetic sensor element, particularly a GMR sensor (12), for sensing magnetic fields generated by labeling particles in reaction to the excitation field. The magnetic excitation fields are generated with non-sinusoidal forms, particularly as square-waves, such that their spectral range comprises a plurality of frequency components. Magnetic particles with different magnetic response characteristics can then be differentiated according to their reactions to the different frequency components of the excitation fields. The magnetic excitation field and the sensing current driving the GMR sensor (12) are preferably generated with the help of ring modulators (22, 24). Moreover, ring modulators (27, 29) may be used for the demodulation of the sensor signal.