Magnetic Particle Flow Channel Layout for Sensitive Sample Analysis

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Solution Overview

Problem

Existing sample analyzers face issues with magnetic particle capture efficiency, leading to decreased sensitivity in immunoanalysis due to particles flowing out without being captured.

Innovation Solution

A sample analyzer with a flow channel design that includes a capture region, a supply unit, a capture unit generating a magnetic field, a magnetic particle distribution adjustment unit, a measurement unit, and a discharge unit to enhance magnetic particle capture efficiency and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic particles are introduced into the flow channel, then detection sensitivity can be improved, but some particles flow out without being captured

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmagnetic particle loss
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The flow channel cross-sectional area is designed to be asymmetric, with the downstream end having a greater area than the upstream end. This asymmetric geometry creates a flow pattern that enhances particle capture efficiency while preventing particles from flowing out uncaptured, thereby improving detection sensitivity without increasing particle loss

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The magnetic field strength is varied locally along the flow channel, with greater magnitude on the downstream side than on the upstream side. This localized variation in magnetic field properties creates optimal capture conditions at different positions, ensuring particles are captured effectively while maintaining high detection sensitivity

Inventive Principle:
Principle #3Local quality

2Productivity

If magnetic field strength is increased to improve capture efficiency, then particle capture improves, but non-uniformity of adsorption increases

Engineering Contradiction:
Improvecapture efficiencyVSAvoidadsorption uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The magnetic field magnitude is progressively increased from upstream to downstream along the flow channel. This gradual parameter change allows particles to be captured incrementally as they flow through, maintaining uniform adsorption distribution while achieving high overall capture efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flow channel is effectively divided into multiple capture zones along its length, with each zone having progressively stronger magnetic field. This segmentation allows particles to be captured in stages, preventing overcrowding in any single location and maintaining adsorption uniformity across the entire channel

Inventive Principle:
Principle #1Segmentation

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 design increases capture efficiency of magnetic particles at a predetermined position, enabling high-sensitivity detection.

Implementation Method 1

a capture unit configured to generate a magnetic field and cause the magnetic particles to be adsorbed to the capture region by the magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

For example, a fluorescent substance is used as the label. In this case, light emission is stronger in proportion to the number of second antibodies bound to the label, that is, the amount of antigen in the complex. By detecting the light emission of the fluorescent substance with a photomultiplier or the like, the antigen in the sample can be quantified.

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP4692804A1Sample analyzer
Publication Date: 2026.02.11 HITACHI HIGH TECH CORP
  • EP4692804A1 patent drawingFigure 1
  • EP4692804A1 patent drawingFigure 2
  • EP4692804A1 patent drawingFigure 3A~3E

AI summary

To increase capture efficiency of magnetic particles at a predetermined position and to perform detection with high sensitivity, the disclosure proposes a sample analyzer including: a flow channel including a capture region defined therein and configured to introduce, into the capture region, a sample liquid containing magnetic particles bound to a specific substance; a supply unit configured to supply the sample liquid to the flow channel; a capture unit configured to generate a magnetic field and cause the magnetic particles to be adsorbed to the capture region by the magnetic field; a magnetic particle distribution adjustment unit configured to make, for a distribution of the magnetic particles in a cross section perpendicular to a flow direction of the sample liquid in the capture region of the flow channel, a distribution in a proximal region closer to the capture region than a center axis of the flow channel denser than a distribution in a distal region farther from the central axis as viewed from the capture region; a measurement unit configured to measure the specific substance adsorbed to the capture region; and a discharge unit configured to discharge the magnetic particles from the flow channel after measurement by the measurement unit (see FIG. 9).