Amyloid Beta Blood Immunoassay Using Anionic Polymers

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Solution Overview

Problem

Immunoassays for amyloid β in blood samples exhibit lower sensitivity compared to cerebrospinal fluid samples, posing a challenge for accurate detection.

Innovation Solution

The immunoassay method involves conducting antigen-antibody reactions in the presence of an anionic polymer, such as dextran sulfate, to enhance sensitivity by reducing the suppression of the reaction caused by a covering substance in blood samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If immunoassay is performed on blood sample using conventional method, then measurement can be conducted, but sensitivity is lower compared to CSF measurement

Engineering Contradiction:
ImprovesensitivityVSAvoidsuppression by covering substance
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

An anionic polymer is introduced as an intermediary substance to counteract the suppression effect of covering substances in blood samples. The anionic polymer interacts with the covering substances to reduce their inhibitory effect on the antigen-antibody reaction, thereby restoring and enhancing measurement sensitivity without requiring changes to the fundamental immunoassay methodology.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical environment of the immunoassay reaction is modified by adding anionic polymers, which change the physical-chemical parameters of the reaction system. This parameter change alters the interaction between covering substances and the antigen-antibody complex, reducing suppression and improving sensitivity. The anionic polymer concentration and type can be optimized to achieve maximum sensitivity enhancement.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If blood sample is used instead of CSF, then non-invasive collection is achieved, but measurement sensitivity decreases

Engineering Contradiction:
Improvesample collectionVSAvoidsensitivity
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The anionic polymer serves as a mediator that enables blood samples to perform as effectively as CSF samples. By adding this intermediary substance, the inherent suppression in blood samples is counteracted, allowing blood to become a viable alternative to CSF for amyloid β measurement while maintaining high sensitivity and the advantage of non-invasive collection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The covering substances in blood samples, which initially cause suppression and reduced sensitivity, are converted into a manageable condition through the addition of anionic polymers. The harmful suppression effect is transformed into a controlled interaction that can be optimized, allowing blood samples to be used effectively despite their complex composition.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If conventional immunoassay method is used, then procedure is simple, but sensitivity is insufficient for blood samples

Engineering Contradiction:
Improveassay procedureVSAvoidsensitivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The assay procedure maintains its simplicity while improving sensitivity through a single parameter change: the addition of anionic polymer to the reaction mixture. This minimal modification to the conventional immunoassay protocol achieves enhanced sensitivity without complicating the overall procedure, making it easily implementable in existing laboratory settings.

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 allows for highly sensitive measurement of amyloid β in blood samples, maintaining sensitivity over time and improving diagnostic accuracy.

Implementation Method 1

carrying out antigen-antibody reaction between amyloid β in a blood sample and an anti-amyloid β antibody or an antigen-binding fragment thereof in the presence of an anionic polymer

Methodology Applied
Scientific EffectAntigen-antibody reaction:

Data Source

PatentEP4130741B1Method for immunoassay of amyloid beta in blood, and kit for same
Publication Date: 2026.01.28 FUJIREBIO CO LTD
  • EP4130741B1 patent drawingFigure 1

AI summary

Disclosed are an immunoassay method capable of highly sensitively measuring amyloid β in a blood sample, and a kit therefor. The immunoassay method for amyloid β is a method of immunoassay of amyloid β in a blood sample, wherein the immunoassay is carried out in the presence of an anionic polymer such as a dextran sulfate salt or a polystyrene sulfonic acid salt. The kit for immunoassay of amyloid β in a blood sample comprises: an anti-amyloid β antibody or an antigen-binding fragment thereof; and an anionic polymer.