摘要:
Described systems and methods allow the detection of and determination of a concentration of a target analyte such as a biological cell, a virus, a polypeptide, a toxin, a pesticide, a drug, a drug residue, or a DNA strand, in a fluid sample. A variable stimulus, such as an oscillating magnetic field or a light beam of oscillating intensity, is applied to the sample, inducing variations in a position or shape of a constituent of the sample, or variations in a fluorescence of the sample. Such variations produce measurable variations in electric and/or optical properties of a sensor, variations which allow the determination of the concentration of the target analyte.
摘要:
The invention relates to a substance determining apparatus for determining a substance within a fluid. Particles, which have attached the substance, are bound to a binding surface (30). A sensing unit (33) is adapted to generate a sensing signal being indicative of at least one of i) a distance between the particles bound on the binding surface (30) and the binding surface (30) and ii) an in-plane position of the particles bound on the binding surface. A binding discrimination unit (34) is adapted to discriminate between different kinds of binding of the particles bound on the binding surface (30) depending on the generated sensing signal. The binding discrimination unit (34) is preferentially a unit for determining the part of the sensing signal being caused by specifically bound particles and to determine the substance based on this determined part of the sensing signal.
摘要:
A method and system for measuring agglutination in a target-induced agglutination assay with one or more magnetic particles is performed in a reaction chamber. After the magnetic particles, which are capable of binding to a target are provided in the assay, an agglutination process is performed resulting in agglutinated particles. Further an alternating current magnetic field (HAC) is applied to the assay. The method further includes measuring an effect of the HAC on the one or more magnetic particles unattached to any surface. The measured effect is indicative of one or more agglutination parameters.
摘要:
Chips that include one or more particle manipulation mechanisms, or force transduction elements, provided at specific locations to manipulate and localize particles proximal the substrate surface. In one embodiment, individually addressable magnetic control mechanisms such as electric coils are provided at specific locations to create a magnetic field to attract magnetic particles, such a magnetic or magnetizable beads, to those specific locations. In another embodiment, electrostatic control mechanisms such as electrodes are provided to attract and manipulate electrically charged micro-particles. A location may include a crater or well formed in the substrate, or it may include an element on the surface of the substrate. In some embodiments, one or more sensors are located proximal specific locations, e.g., specific craters, so as to analyze specific conditions at each location. In other embodiments, multiple locations share one or more sensors.
摘要:
An integrated sensor that is capable of discriminating the distance of a label from the sensor without using an optical signal. The label is attached to a single probe molecule or a group of probe molecules that interacts with a single or group of target molecules. As a consequence of this interaction, the probe molecule and/or the target molecule undergo a conformal change. This conformal change leads to perturbations in the distance of the label from the sensor. Thus, measurements and properties such as the concentration and the identity of one or more target molecules can be discerned from signals generated by the sensor (or by a plurality of sensors in a sensor array) and subjected to analysis using general purpose programmable computers programmed with suitable software that controls the analytical process, and such measurements and properties can be provided as a result of the analysis.
摘要:
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 (γTf1+βTf2), which γT and βT are positive integers and the frequency f1 and the frequency f2 are two different frequencies.
摘要:
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.
摘要:
The invention relates to a method and a sensor device (100) for the detection of magnetic particles (M) in a sample. The magnetic particles (M) can bind to binding sites (Z) at a binding surface (12), where they can be detected by a detection unit (13, 14). A controller (15) is provided for controlling magnetic attraction (B) of the magnetic particles (M) towards the binding surface (12) in dependence on the detection signal (S) of the detection unit (14) in such a way that rotational relaxation conditions for the magnetic particles (M) are changed. In particular, this change can be controlled to maximize the binding of magnetic particles (M) to the binding surface (12) within a given measurement time. The change can for example be achieved by repeatedly switching the magnetic attraction off for prolonged periods, giving the magnetic particles (M) better chances to orient properly with respect to the binding surface (12).