Biosensor using magnetically-detected label
First Claim
1. An apparatus for detecting a target molecular species, comprising:
- a magnetoresistive or magnetostrictive magnetic field sensor having attached thereto binding molecules which selectively bind the target molecular species;
magnetizable label particles bearing binding molecules which;
(1) selectively bind the target molecular species or, in the alternative,(2) selectively bind the sensor bound binding molecules, and(i) compete for said selective binding of said sensor bound binding molecules with said selective binding of said target molecular species to said sensor bound binding molecules, or(ii) are displaced from said sensor bound binding molecules by said selective binding of said target molecular species to said sensor bound binding molecules,whereby the label particles attach to the magnetic field sensor as a result of said selective binding;
magnetizing means for magnetizing the attached label particles; and
detection means for monitoring a magnetoresistive or magnetostrictive response of the magnetic field sensor to a magnetic field produced by one or more magnetized label particles attached to said magnetic field sensor, whereby the concentration of the target molecule is determined.
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Accused Products
Abstract
This method and apparatus for detecting target molecules in a liquid phase. The apparatus monitors whether the target molecule has selectively bound to recognition agents on the surface of a magnetic field sensor by monitoring the output of the sensor. The recognition agents which selectively bind target molecules are covalently bound to microfabricated magnetic field sensors. These sensors are then exposed to a sample suspected of containing the target molecules, whereupon the recognition agents bind to and immobilize any target molecules present. Depending on the embodiment, recognition agents that selectively bind the target molecule, or recognition agents that selectively bind the sensor-bound recognition agents, are covalently bound to magnetizable particles. These particles are then added to the sensors and, again depending on the embodiment, attach either to any immobilized target molecules or to sensor-bound recognition agents. Unattached particles are removed, and the magnetic particles are then magnetized. A change in the output of the magnetic field sensors indicates the presence of magnetic particles bound to the sensors, and thereby indicates the presence and concentration of target molecule in the sample.
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Citations
37 Claims
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1. An apparatus for detecting a target molecular species, comprising:
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a magnetoresistive or magnetostrictive magnetic field sensor having attached thereto binding molecules which selectively bind the target molecular species; magnetizable label particles bearing binding molecules which; (1) selectively bind the target molecular species or, in the alternative, (2) selectively bind the sensor bound binding molecules, and (i) compete for said selective binding of said sensor bound binding molecules with said selective binding of said target molecular species to said sensor bound binding molecules, or (ii) are displaced from said sensor bound binding molecules by said selective binding of said target molecular species to said sensor bound binding molecules, whereby the label particles attach to the magnetic field sensor as a result of said selective binding; magnetizing means for magnetizing the attached label particles; and detection means for monitoring a magnetoresistive or magnetostrictive response of the magnetic field sensor to a magnetic field produced by one or more magnetized label particles attached to said magnetic field sensor, whereby the concentration of the target molecule is determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for detecting the presence of a target molecular species in a sample suspected of including said target species, comprising the steps of:
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a) providing a detector comprising a magnetoresistive or magnetostrictive magnetic field sensor having binding molecules which selectively bind to the target molecules and which are bound to the sensor; b) bringing the sample and one or more species of magnetizable label particles into contact with the detector at the same or at different times, said label particles having attached binding molecules that; (1) selectively bind the target species, or, in the alternative; (2) selectively bind the sensor-bound binding molecules, and (i) compete for said selective binding of said sensor-bound binding molecules with said selective binding of said target molecular species to said sensor-bound binding molecules, or (ii) are displaced from said sensor-bound binding molecules by said selective binding of said target molecular species to said sensor-bound binding molecules, whereby said label particles attach to the sensor as a result of said selective binding, the number of said label particles attached to said sensor being related to the concentration of the target species; c) removing unbound label particles; d) magnetizing the remaining bound label particles; and e) monitoring a magnetoresistive or magnetostrictive response of said magnetic field detector to a magnetic field produced by one or more magnetized label particle attached to said magnetic field sensor, whereby the concentration of the target molecule is determined. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification