Sub-400 nm Latex Affinity Particles for IgG Detection

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Solution Overview

Problem

Existing latex agglutination methods for detecting immunoglobulin G in human specimens face challenges in achieving both high sensitivity and a wide measurement range, particularly in distinguishing between different antibody abundances to accurately diagnose infections like HCV.

Innovation Solution

The use of affinity particles with a volume-average diameter of 400 nm or less, carrying a protein with a molecular weight of 10,000 or more, and a surface antigen amount between 1.0 µg to 20.0 µg per 1 mg of the particle, optimized to enhance detection sensitivity and measurement range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the particle diameter is increased to improve detection sensitivity, then the detection sensitivity is improved, but the measurement range is narrowed

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurement range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent optimizes the particle diameter parameter to 400 nm or less and controls the protein amount to 1.0-20.0 µg per 1 mg of particle, achieving a balance between detection sensitivity and measurement range by carefully adjusting these physical and chemical parameters

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite affinity particles combining latex particles with specific proteins (molecular weight ≥10,000) carried on their surface, creating a multi-component system that simultaneously achieves high sensitivity and wide measurement range through the synergistic effect of the particle matrix and protein coating

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If the protein amount on particle surface is increased to enhance detection sensitivity, then the detection sensitivity is improved, but the measurement range is reduced

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurement range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent precisely controls the protein amount parameter within 1.0-20.0 µg per 1 mg of particle, optimizing the balance between having sufficient antigen for high sensitivity detection while maintaining enough space for agglutination reactions that enable wide measurement range

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the antigen molecular weight is increased to improve detection accuracy, then the detection accuracy is improved, but the measurement range is narrowed

Engineering Contradiction:
Improvedetection accuracyVSAvoidmeasurement range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent specifies an antigen molecular weight of 10,000 or more, which provides sufficient epitopes for accurate detection while controlling the overall protein amount to maintain measurement range capability

Inventive Principle:
Principle #35Parameter changes

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 improves detection sensitivity and expands the measurement range, allowing for more accurate differentiation between antibody levels, thereby enhancing the efficiency of infection diagnosis.

Implementation Method 1

the target substance (immunoglobulin) in the specimen and a latex particle having carried thereon an antigen having an affinity for the target substance are caused to react with each other

Methodology Applied
Scientific EffectAntigen-antibody reaction:

Implementation Method 2

a diagnosis is made by optically detecting an agglutination reaction between the particles through the antigen-antibody reaction

Methodology Applied
Scientific EffectAgglutination:

Implementation Method 3

a diagnosis is made by optically detecting an agglutination reaction between the particles through the amount of a change in, for example, scattered light intensity

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4628894A1Affinity particle, test reagent, and detection method for detecting target immunoglobulin g in human specimen
Publication Date: 2025.10.08 CANON KK
  • EP4628894A1 patent drawingFigure 1-1~1-2
  • EP4628894A1 patent drawingFigure 1-3~1-4
  • EP4628894A1 patent drawingFigure 1-5~1-6

AI summary

Provided is an affinity particle for detecting immunoglobulin G in a human specimen by a latex agglutination method, wherein the affinity particle has a volume-average particle diameter of 400 nm or less, wherein the affinity particle includes a latex particle and a protein carried on a surface of the latex particle, wherein the protein contains an antigen having a molecular weight of 10,000 or more, and wherein an amount of the protein carried on the surface of the latex particle is 1.0 µg or more and 20.0 µg or less per 1 mg of the affinity particle.