Optical Waveguide Sensor with Magnetic Particle Separation

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Solution Overview

Problem

Current immunoassay methods using optical waveguides face limitations in sensitivity due to non-specific absorption of magnetic fine particles, leading to measurement errors, especially when high detection sensitivity is required for certain inspection items.

Innovation Solution

A measuring system incorporating an optical waveguide, magnetic fine particles, and a magnetic field applying unit, where the magnetic fine particles are dispersed and moved using a magnetic field to separate non-specifically absorbed particles, allowing precise measurement of particles bonded through antigen-antibody reactions, thereby reducing measurement errors and enhancing sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic fine particles are used to enhance detection sensitivity through antigen-antibody reactions, then detection sensitivity is improved, but non-specific absorption of particles causes measurement errors

Engineering Contradiction:

Improvedetection sensitivityVSAvoidmeasurement accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The measurement process is divided into distinct phases: first allowing antigen-antibody reactions to occur, then applying a magnetic field to separate specifically bound particles from non-specifically adsorbed particles. This segmentation enables selective measurement of specific binding signals while eliminating background noise from non-specific adsorption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful non-specifically adsorbed particles are extracted and removed from the measurement system by applying a magnetic field. This separates the problematic non-specific particles from the specifically bound particles, allowing measurement of only the relevant signal without interference from non-specific adsorption.

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If fine particles are bonded to the optical waveguide surface to detect subject substances, then quantification capability is improved, but non-specific adhesion causes measurement errors

Engineering Contradiction:

Improvequantification accuracyVSAvoidnon-specific adhesion

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A magnetic field is introduced as an intermediary force to manipulate the fine particles. This magnetic field acts as a mediator that can selectively move non-specifically adsorbed particles away from the optical waveguide surface without affecting specifically bound particles, thereby eliminating measurement errors caused by non-specific adhesion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If high concentrations of marking bodies are used to increase color forming reaction, then sensitivity is improved, but the reaction produces no more than one color forming reaction per antigen-antibody pair limiting sensitivity

Engineering Contradiction:

Improvedetection sensitivityVSAvoidreaction limitation

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The optical detection system is replaced with a magnetic manipulation and optical detection hybrid system. Instead of relying solely on color forming reactions with marking bodies, the invention uses magnetic fields to manipulate particles and detects their presence through optical means, bypassing the limitation of single-color-reaction-per-pair and enabling higher sensitivity detection.

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

The system achieves higher detection sensitivity and reduces measurement errors by selectively isolating particles not involved in antigen-antibody reactions, enabling accurate quantification of subject substances even at low concentrations.

Implementation Method 1

An optical waveguide has a function of guiding light

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a magnetic field applying unit which applies a magnetic field to the magnetic fine particles

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS9274104B2Measuring system using optical waveguide, measuring device, measuring method, optical waveguide type sensor chip, and magnetic fine particle

Publication Date: 2016.03.01 CANON MEDICAL SYST CORP

AI summary

According to one embodiment, a measuring system using an optical waveguide is provided. The measuring system has an optical waveguide, magnetic fine particles, a magnetic field applying unit, a light source and a light receiving element. The optical waveguide has a sensing area to which first substances having a property of specifically bonding to subject substances to be measured are fixed. Second substances having a property of specifically bonding to the subject substances are fixed to the magnetic fine particle. The magnetic field applying unit generates a magnetic field for moving the magnetic fine particles. The light source inputs a light into the optical waveguide. The light receiving element receives the light output from the optical waveguide.