Method for magnetically detecting microscopic biological objects and associated devices

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Solution Overview

Problem

Existing magnetic detection methods using magnetoresistive sensors struggle to distinguish between labeled biological objects and aggregates of magnetic beads due to the proportional relationship between dipole field and passage height, leading to false positives and inability to determine magnetic moment independently.

Innovation Solution

A biochip with two magnetic field sensors on either side of a microfluidic channel measures synchronized electrical signals to calculate passage height and magnetic moment of objects using a reference curve, allowing discrimination between biological objects and bead aggregates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetoresistive sensors are used to detect magnetic objects in a microfluidic channel, then detection sensitivity is improved, but the ability to distinguish between labeled biological objects and magnetic bead aggregates deteriorates

Engineering Contradiction:

Improvedetection sensitivityVSAvoiddiscrimination capability

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces a new dimension of analysis by measuring both the amplitude of the dipole field signal and the passage height of magnetic objects through the microfluidic channel. By combining these two independent measurements, the system can uniquely identify labeled biological objects versus magnetic bead aggregates, resolving the discrimination problem while maintaining high detection sensitivity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses passage height as an intermediary parameter to differentiate between true positive signals (labeled biological objects) and false positive signals (magnetic bead aggregates). This intermediate measurement allows the system to make accurate discriminations without requiring additional complex sensing mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If excess magnetic beads are used to ensure proper labeling of biological objects, then labeling reliability is improved, but the number of false positive signals increases

Engineering Contradiction:

Improvelabeling reliabilityVSAvoidfalse positive signals

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system continuously monitors the passage height of magnetic objects as they traverse the microfluidic channel and uses this feedback information to differentiate between properly labeled biological objects and spurious magnetic bead aggregates. This real-time feedback mechanism allows the system to maintain high labeling reliability while filtering out false positive signals through intelligent signal processing

Inventive Principle:

Principle #23Feedback

3Device complexity

If a single dipole field measurement is used to detect magnetic objects, then device simplicity is maintained, but the ability to determine magnetic moment independently deteriorates

Engineering Contradiction:

Improvedevice simplicityVSAvoidmagnetic moment determination

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent adds a spatial dimension by measuring the passage height of magnetic objects through the microfluidic channel in addition to the dipole field amplitude measurement. This dual-measurement approach enables independent determination of magnetic moment while keeping the device structure relatively simple, avoiding the need for complex multi-sensor arrays

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 improves discrimination of magnetic objects by accurately determining passage height and magnetic moment, reducing false positives and enabling reliable detection and counting of biological objects.

Implementation Method 1

magnetoresistive sensors using Giant MagnetoResistance (GMR) or Tunnel MagnetoResistance (TMR)

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Implementation Method 2

The dipole field emitted by each marked biological object passing in proximity to said magnetoresistive sensor is measured

Methodology Applied

Scientific EffectMagnetic dipole field: Magnetic Field

Data Source

PatentUS20250377356A1Method for magnetically detecting microscopic biological objects and associated devices

Publication Date: 2025.12.11 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

A method for determining the magnetic moment of a magnetic object circulating in a microfluidic channel, on which two magnetic field sensors are disposed on either side, the method including receiving two electrical signals; calculating the passage height of the magnetic object into the microfluidic channel from the ratio of the electrical signals and by a reference curve; and calculating the magnetic moment of the magnetic object from the passage height determined and one of the electrical signals.