System and method for processing analyte signals in GMR-based detection of biomarkers
Inventors
Klein, Todd Michael • SANDSTEDT, Michael Monroe Reinhart • SONG, Keping
Assignees
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Publication Number
US-12241851-B2
Publication Date
2025-03-04
Expiration Date
Abstract
A signal processing system used for GMR-based detection of a target analyte in a sample under test, comprising: a measurement circuit configuration unit configured to build a GMR sensor measurement circuit by routing in at least one GMR sensor, and to build a reference resistor measurement circuit by routing in at least one reference resistor; a magnetic field excitation unit configured to apply an AC magnetic field of frequency ω2 to the at least one GMR sensor; a carrier signal applying unit configured to apply a carrier signal of frequency ω1 to the GMR sensor measurement circuit, and apply carrier signals of frequency ω1, ω1+ω2, and ω1−ω2 to the reference resistor measurement circuit; a measurement signal pick-up unit coupled to the measurement circuits, configured to collect reference resistor measurement signals from the reference resistor measurement circuit and GMR sensor measurement signals from the GMR sensor measurement circuit; and a phase sensitive solution unit coupled to the measurement signal pick-up unit, configured to analytically solve for resistance change of the at least one GMR sensor based on both the reference resistor measurement signals from the reference resistor measurement circuit and the GMR sensor measurement signals from the GMR sensor measurement circuit.
Core Innovation
The invention relates to a signal processing system for Giant Magneto-Resistive (GMR)-based detection of a target analyte in a sample under test. A magnetic field excitation unit applies an Alternating Current (AC) magnetic field of frequency ω2 to the at least one GMR sensor, while a carrier signal applying unit applies a carrier signal of frequency ω1 to the GMR sensor measurement circuit and also applies carrier signals of frequencies ω1, ω1+ω2, and ω1−ω2 to a reference resistor measurement circuit. The system builds a GMR sensor measurement circuit and a reference resistor measurement circuit, each including a voltage divider.
The system collects reference resistor measurement signals from the reference resistor measurement circuit and GMR sensor measurement signals from the GMR sensor measurement circuit with a measurement signal pick-up unit. A phase sensitive solution unit analytically solves for resistance change of the at least one GMR sensor based on both the reference resistor measurement signals and the GMR sensor measurement signals. The analytical solution uses phase-sensitive processing to relate the sensor response to the reference information in order to compute the resistance change.
The resistance change is used to determine magnetoresistance change and thereby to support detection of the target analyte. A detection result determination unit determines whether the target analyte is present and/or determines the concentration of the target analyte in the sample under test based on the solved magnetoresistance change.
Claims Coverage
The document provides one independent claim for a signal processing system used for GMR-based detection, with dependent claims narrowing circuit implementations, the phase-sensitive solution, and detection/concentration determination.
Signal processing system for GMR-based detection using reference resistor measurement with phase-sensitive analytical solution
A signal processing system comprising a measurement circuit configuration unit to build a GMR sensor measurement circuit and a reference resistor measurement circuit, a magnetic field excitation unit to apply an AC magnetic field of frequency ω2 to the GMR sensor, a carrier signal applying unit to apply a carrier signal of frequency ω1 to the GMR sensor measurement circuit and carrier signals of frequencies ω1, ω1+ω2, and ω1−ω2 to the reference resistor measurement circuit, a measurement signal pick-up unit to collect reference resistor measurement signals and GMR sensor measurement signals, and a phase sensitive solution unit to analytically solve for resistance change of the at least one GMR sensor based on both sets of measurement signals.
Analytical phase-sensitive computation producing in-phase and quadrature references and closed-form resistance change
The phase sensitive solution unit generates in-phase and quadrature sinusoid reference signals at all frequencies of interest, multiplies the measurement signals by those references, integrates the products, and uses a close-form solver to determine the GMR sensor resistance change.
Carrier voltage drive with Wheatstone full bridge and functionalized/reference connections swapped between bridge arms
The carrier signal applying unit uses a carrier voltage source, and the GMR sensor measurement circuit is a Wheatstone full bridge with first and second bridge arms whose voltage dividers include a target-analyte functionalized GMR sensor and a reference element, with functionalized/reference connections swapped between the arms.
Reference resistor measurement using a Wheatstone full bridge with three matched resistors and one mismatched resistor
The reference resistor measurement circuit is a Wheatstone full bridge using four reference resistors, where three of the four reference resistors have a matched resistance value and the fourth reference resistor has a mismatched resistance value.
Carrier current source drive with Anderson loop circuits
The carrier signal applying unit is a carrier current source, and both the reference resistor measurement circuit and the GMR sensor measurement circuit include Anderson loop circuits; the GMR sensor voltage divider is formed by a target-analyte functionalized GMR sensor and a reference element.
Determination of analyte presence and concentration from solved magnetoresistance change
From the solved magnetoresistance change of the at least one GMR sensor, a detection result determination unit determines whether the target analyte is present and/or determines the concentration in the sample under test.
Across the independent claim and its dependents, the inventive coverage centers on dual-frequency excitation with carrier/reference division and a phase sensitive solution unit that analytically solves for GMR resistance change using both sensor and reference measurements, followed by detection result determination using the solved magnetoresistance change.
Stated Advantages
Enables detection of whether the target analyte is present and determination of the concentration of the target analyte in the sample under test.
Documented Applications
GMR-based detection of a target analyte in a sample under test, including determining presence/absence and concentration based on solved magnetoresistance change.
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