Magnetic Biosensor Stray Field Magnetization

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Solution Overview

Problem

Conventional magnetic biosensing schemes require an external magnetic field generator, leading to high power consumption and limited portability, which is detrimental for point-of-care applications.

Innovation Solution

A patterned groove structure in the magnetic biosensor utilizes stray magnetic fields from the device to magnetize magnetic nanoparticles, eliminating the need for an external magnetic field generator and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external magnetic field generator is used to magnetize magnetic nanoparticles, then the magnetization of MNPs is achieved, but power consumption increases and portability is limited

Engineering Contradiction:

Improvemagnetization of magnetic nanoparticlesVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The magnetic biosensor uses its own stray magnetic field to magnetize the magnetic nanoparticles, eliminating the need for an external magnetic field generator. The sensor's inherent magnetic properties enable it to perform the magnetization function that previously required separate external equipment, thereby reducing power consumption and enabling portability for point-of-care applications

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent combines the magnetization function with the sensing function by using the same magnetic biosensor device to both detect and magnetize the nanoparticles. This integration eliminates the need for separate external magnetic field generators, reducing system complexity and power requirements

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If an external magnetic field generator is used, then magnetic nanoparticles can be magnetized, but device complexity increases

Engineering Contradiction:

Improvemagnetization of magnetic nanoparticlesVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic biosensor performs self-magnetization using its own stray field, eliminating the need for external magnetic field generators. This self-service approach reduces the number of external components and simplifies the overall system structure while maintaining reliable nanoparticle magnetization

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent merges the magnetization and sensing functions into a single integrated device. The magnetic biosensor simultaneously performs detection and magnetization, eliminating the need for separate external magnetic field generators and reducing system complexity

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If large current is used to generate magnetic field from built-in current lines, then magnetic nanoparticles can be magnetized without external electromagnets, but heating effects and dielectric breakdown occur

Engineering Contradiction:

Improveelimination of external electromagnetsVSAvoidheating effects and dielectric breakdown

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The magnetic biosensor uses its own stray magnetic field to magnetize nanoparticles, eliminating the need for large currents in built-in current lines. This approach avoids the heating effects and dielectric breakdown problems associated with high current operation while still achieving effective nanoparticle magnetization

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces the current-based magnetic field generation mechanism with a magnetic field-based approach using stray fields from the sensor's magnetic layers. This substitution eliminates the need for large electrical currents and their associated harmful effects while maintaining the ability to magnetize nanoparticles

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach enables efficient detection of magnetic nanoparticles with a high signal level, achieving a maximum magnetoresistive ratio change of 8.9×10−5, sufficient for detecting 10 nanoparticles, and is applicable to various spintronic and magnetic sensing devices, enhancing detection efficiency and accuracy while minimizing power usage.

Implementation Method 1

utilizes stray field from the magnetic biosensor to magnetize and bind magnetic labels

Methodology Applied

Scientific EffectStray magnetic field: Magnetic Field

Implementation Method 2

The dipole field from the specifically bound magnetized MNPs will change the overall effective magnetic field on the sensing layer of the magnetic biosensor, thus generating an electrical signal from the biosensor

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Implementation Method 3

Hall biosensors or Giant magneto impedance (GMI) biosensors

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS9927431B2External field—free magnetic biosensor

Publication Date: 2018.03.27 REGENTS OF THE UNIVERSITY OF MINNESOTA

AI summary

A biosensor includes a magnetic structure having grooved surface to biologically bond magnetic labels to a biological substance within the grooves. The grooves are positioned within the magnetic structure so that stray magnetic fields from the magnetic structure magnetize magnetic labels within the groove. The magnetic labels may be magnetic nanoparticles or magnetic microbeads. The techniques may reduce or eliminate the usage of any external magnetic field generator, e.g., electromagnets or current lines.