Magnetic Tunnel Junction Immunosensing on Lipid Layers With Low Background
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Solution Overview
Problem
Existing ELISA methods face challenges with sensitivity and specificity due to fragile immune complexes leading to false positive signals and limitations in signal amplification, particularly in sandwich formats.
Innovation Solution
A method utilizing a sensor element with an anchor layer, a first binding agent anchored in the layer, a second binding agent with a magnetic label immobilized on a solid support, and a magnetic tunnel junction in proximity to generate a signal for detecting the analyte complex formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ELISA methods use traditional optical detection with enzyme-linked reagents, then the assay can detect analytes, but the sensitivity is limited and background noise is high due to fragile immune complexes
Solution Approach 1:
The patent replaces the traditional optical detection system (enzymatic reactions, color development, spectrophotometry) with a magnetic detection system using magnetic tunnel junctions (MTJs). The MTJ detects the magnetic signal from magnetic labels attached to immune complexes, eliminating the need for enzymatic amplification and optical measurement, thereby improving sensitivity and reducing background noise associated with fragile complex formation
Solution Approach 2:
The invention changes the detection parameter from optical properties (light absorption, color intensity) to magnetic properties (magnetic moment, magnetic signal). This parameter change allows detection based on the intrinsic magnetic signal of the magnetic label rather than requiring enzymatic conversion to an optical signal, improving detection precision and reliability
2Measurement precision
If sandwich ELISA format is used to improve specificity, then analyte detection is enhanced, but the complexity of multiple binding agents and washing steps increases
Solution Approach 1:
The magnetic detection system replaces the complex optical detection procedure requiring multiple washing steps to remove unbound reagents. The magnetic label provides a direct, specific signal from bound complexes without requiring extensive washing, simplifying the overall assay procedure while maintaining sandwich ELISA specificity
Solution Approach 2:
The magnetic label attached to the detection reagent provides self-contained signal generation and localization. The magnetic signal inherently indicates bound complexes without requiring external enzymatic conversion or multiple processing steps, reducing assay complexity while maintaining detection specificity
3Device complexity
If traditional optical detection methods are used, then the setup is simple, but signal amplification is limited and background noise reduces detection accuracy
Solution Approach 1:
The magnetic tunnel junction detection system replaces traditional optical detection while maintaining relative simplicity. The MTJ provides direct electrical readout of magnetic signals from labels, eliminating the need for complex optical paths, light sources, and photodetector systems, while achieving superior signal-to-noise ratio through direct magnetic signal detection
Solution Approach 2:
Changing from optical to magnetic detection parameters enables signal amplification through the high sensitivity of magnetic tunnel junctions to magnetic field changes. The magnetic signal from labels can be detected with high precision by the MTJ, improving signal-to-noise ratio without requiring enzymatic amplification cascades
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves sensitivity and reduces background noise, enabling accurate and specific detection of analytes with improved signal generation and reduced need for washing steps.
Implementation Method 1
a magnetic tunnel junction in functional proximity to the second binding agent which generates a signal elicited in proximity to the at least one magnetic label of the second binding agent
Data Source
Figure 1
Figure 2A~2B
AI summary
The present invention concerns the field of diagnostics. In particular, it relates to a method for determining an analyte suspected to be present in a sample comprising contacting said sample with a sensor element comprising an anchor layer which is present on a solid support, a first binding agent which is capable of specifically binding to the analyte, which is anchored in the anchor layer, a second binding agent which is capable of specifically binding to the analyte when bound to the first binding agent and which is immobilized on the solid support, said second binding agent comprising at least one magnetic label, and a magnetic tunnel junction in functional proximity to the second binding agent which generates a signal elicited in proximity to the at least one magnetic label of the second binding agent, for a time and under conditions which allow for specific binding of the analyte suspected to be present in the sample to the first binding agent and specific binding of the second binding agent to the analyte bound to the first binding agent and detecting the formation the complex of first binding agent, analyte and second binding agent based on an altered signal which is generated by the magnetic tunnel junction whereby the analyte is determined. The present invention, further, relates to a device and a kit for determining an analyte suspected to be present in a sample and to the use of said device for determining an analyte suspected to be present in a sample.