Superabsorbent Polymer Concentration for Low-Level Antigen Detection

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Solution Overview

Problem

Existing immunological test methods, such as immunochromatography, face challenges in achieving high detection sensitivity, particularly when dealing with sample solutions having extremely low antigen concentrations.

Innovation Solution

The method involves concentrating an antigen-containing solution using a superabsorbent polymer with a specific swelling ratio, incorporating impurities like urea into the polymer, and utilizing a monoclonal antibody in an antigen-antibody reaction, followed by a silver amplification step to enhance detection sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional immunochromatography is used, then the operation is easy and measurement can be carried out in a short time, but the detection sensitivity is insufficient for samples with extremely low antigen concentrations

Engineering Contradiction:
Improvedetection sensitivityVSAvoidtest method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention applies preliminary concentration action by mixing the sample with superabsorbent polymer beads before the immunochromatography detection step. The beads concentrate antigens from dilute samples (including urine) through water absorption, preparing the sample in advance for more sensitive detection. This preliminary concentration step enables detection of antigens at concentrations that would be below the detection limit of conventional immunochromatography alone.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If superabsorbent polymer is used to concentrate antigens, then detection sensitivity improves, but impurities like urea are also concentrated which may inhibit the antigen-antibody reaction

Engineering Contradiction:
Improvedetection sensitivityVSAvoidinhibitory effect of impurities
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention applies local quality differentiation by selecting superabsorbent polymer beads with specific properties (swelling ratio of 10-100 g/g, specific particle size ranges) that preferentially absorb water and small molecules like urea while allowing antigens to remain in the supernatant or be gently concentrated. This localized selective absorption property enables concentration of antigens while minimizing co-concentration of inhibitory impurities, resolving the contradiction between sensitivity improvement and impurity inhibition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the physical-chemical parameters of the concentration medium by using superabsorbent polymers with specifically controlled swelling ratios (10-100 g/g) and particle sizes (0.01-2.0 mm). By adjusting these parameters, the system optimizes the balance between water absorption capacity (for concentration) and selectivity (for minimizing impurity co-concentration), thereby improving detection sensitivity while reducing inhibitory effects.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the swelling ratio of superabsorbent polymer is increased to improve concentration efficiency, then more water is absorbed, but the polymer may become too bulky and difficult to handle

Engineering Contradiction:
Improveconcentration efficiencyVSAvoidhandling ease
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The invention optimizes the swelling ratio parameter within the specific range of 10-100 g/g, avoiding both too-low values (insufficient concentration) and too-high values (excessive bulkiness). This parameter optimization ensures that the superabsorbent polymer beads maintain adequate water absorption capacity for effective antigen concentration while remaining manageable in size for practical handling and mixing operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality control by specifying particle size ranges (0.01-2.0 mm) that balance surface area (for absorption efficiency) with handling characteristics. Smaller particles provide greater surface area for water absorption but may be difficult to handle, while larger particles are easier to handle but have reduced absorption efficiency. The specified range optimizes this local quality balance.

Inventive Principle:
Principle #3Local quality

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 significantly improves detection sensitivity by concentrating antigens while minimizing the inhibitory effect of impurities, allowing for precise and reproducible antigen detection in low-concentration samples.

Implementation Method 1

a concentration step of concentrating an antigen-containable solution by mixing the antigen-containable solution with a superabsorbent polymer to obtain an antigen-concentrated solution by incorporating impurities including urea contained in the antigen-containable solution together with water into the superabsorbent polymer

Methodology Applied
Scientific EffectOsmosis: Osmosis

Implementation Method 2

a detection step of detecting an antigen in the antigen-concentrated solution using an antigen-antibody reaction, in which the swelling ratio of the superabsorbent polymer ranges from including 20 g/g to including 500 g/g

Methodology Applied
Scientific EffectAntigen-antibody reaction:

Implementation Method 3

allowing for precise and reproducible antigen detection in low-concentration samples

Methodology Applied
Scientific EffectSilver amplification:

Data Source

PatentEP4040151B1Immunological test method
Publication Date: 2025.08.13 FUJIFILM CORP
  • EP4040151B1 patent drawingFigure 1
  • EP4040151B1 patent drawingFigure 2A~2D
  • EP4040151B1 patent drawingFigure 3A~3D

AI summary

There is provided an immunological test method having high detection sensitivity. The immunological test method includes a concentration step of concentrating an antigen-containable solution by mixing the antigen-containable solution with a superabsorbent polymer to obtain an antigen-concentrated solution, and a detection step of detecting an antigen in the antigen-concentrated solution using an antigen-antibody reaction, in which a swelling ratio of the superabsorbent polymer is more than 0.2 g/g and less than 800 g/g, and an antibody that is used in the antigen-antibody reaction is a monoclonal antibody.