Magnetic Tunnel Junction Analyte Detection Without ELISA Wash Steps

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Solution Overview

Problem

Existing immunoassays, such as ELISA, face challenges with sensitivity and specificity due to fragile immune complexes and potential false positive signals, necessitating validation and limiting their effectiveness in detecting analytes.

Innovation Solution

A method utilizing a sensor element with a binding agent capable of specifically binding to an analyte and comprising a magnetic label, in functional proximity to a magnetic tunnel junction, which generates an altered signal upon binding, allowing for improved detection through altered signal measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ELISA with multiple reagents and washing steps is used, then analyte detection capability is achieved, but sensitivity and specificity are limited due to fragile immune complexes and false positive signals

Engineering Contradiction:
Improvedetection accuracyVSAvoidassay format complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the fragile immune complexes and multiple washing steps from the traditional ELISA format. By using a single-step binding approach with magnetic beads coated with capture antibodies, the assay removes the need for sequential reagent additions and extensive washing, thereby reducing complexity while maintaining or improving detection reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention inverts the traditional ELISA sequence by performing analyte capture and detection simultaneously in a single step. Instead of sequentially adding capture antibody, washing, then adding detection antibody with another wash, the method uses magnetic beads with capture antibodies to directly bind and detect the analyte in one operation, reversing the conventional multi-step workflow.

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If sandwich ELISA format with capture and detection antibodies is used, then analyte specific binding is achieved, but false positive signals occur due to undesired binding of detection antibodies

Engineering Contradiction:
Improveanalyte detection precisionVSAvoidfalse positive signals
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes the detection antibody step from the sandwich ELISA format. By using magnetic beads coated with capture antibodies that directly bind the analyte and generate a magnetic signal, the method eliminates the need for detection antibodies, thereby removing the source of undesired binding and false positive signals while maintaining analytical precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the biochemical detection mechanism (detection antibodies binding to analyte-capture antibody complexes) with a physical detection mechanism (magnetic signal detection). The magnetic beads provide a direct physical signal that does not require additional antibody binding steps, eliminating false positives caused by undesired antibody interactions while maintaining measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If multiple reagents are sequentially added and washed away, then complete immunoassay reaction is achieved, but time consumption increases and sensitivity is limited

Engineering Contradiction:
Improveanalyte detection sensitivityVSAvoidassay time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The invention applies preliminary action by pre-coating magnetic beads with capture antibodies before sample addition. This pre-preparation allows the analyte to be captured immediately upon sample contact with the beads, eliminating the need for sequential reagent additions and incubation steps, thereby reducing assay time while maintaining or enhancing detection sensitivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention merges the capture and detection steps into a single simultaneous operation. By using magnetic beads that both capture the analyte and provide a detectable magnetic signal, the method combines functions that were previously separated into multiple steps, thereby reducing total assay time while improving sensitivity through direct magnetic detection without signal loss from washing steps.

Inventive Principle:
Principle #5Merging (Combining)

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

The method enhances sensitivity and specificity in detecting analytes by utilizing a magnetic tunnel junction to generate and measure altered signals, enabling accurate determination of analytes with improved precision.

Implementation Method 1

a magnetic tunnel junction generating a signal which is altered upon binding of the analyte to the binding agent

Methodology Applied
Scientific EffectMagnetic tunnel junction effect: Magnetoresistance

Data Source

PatentEP4356128B1Methods for detecting an analyte using structure switching binding agents
Publication Date: 2026.02.04 F HOFFMANN LA ROCHE & CO AG
  • EP4356128B1 patent drawingFigure 1A~1B

AI summary

The present invention relates to diagnostic test and technology. In particular, it relates to a method for determining an analyte suspected to be present in a sample comprising contacting said sample with at least one sensor element comprising at least one binding agent which is capable of specifically binding to the analyte and which comprises at least one magnetic label; and in functional proximity thereto a magnetic tunnel junction generating a signal which is altered upon binding of the analyte to the 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 at least one binding agent, measuring an altered signal generated by the magnetic tunnel junction upon analyte binding to the at least one binding agent comprising the at least one magnetic label, and determining the analyte based on the altered signal which is generated by the magnetic tunnel junction. The present invention further relates to a device for determining an analyte suspected to be present in a sample and for using such a device. Moreover, the present invention furthermore relates to an aptamer which is capable of specifically binding to an analyte and which comprises at least one magnetic label and a method for identifying such an aptamer. Finally, the invention relates to a kit for determining an analyte suspected to be present in a sample.