Immunoassay Array Sensitivity via Intermediary Antibody Blocking

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Solution Overview

Problem

In immunoassays, especially in array formats, background signals due to unspecifically bound immunoglobulins complicate the detection of antigen-specific antibodies, making it difficult to achieve high sensitivity and specificity, particularly in miniaturized test systems where modifying the solid phase or using buffer additives can be laborious and ineffective across multiple tests.

Innovation Solution

The method involves using a binding partner B2 with a label that specifically binds to antigen-specific antibodies on discrete areas of an array support, reducing the detection of unspecifically bound immunoglobulins by recognizing densely packed antigen-specific antibodies while ignoring loosely distributed unspecifically bound ones, thereby minimizing background signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a class-specific labelled antibody is used to detect antigen-specific antibodies, then the detection sensitivity is improved, but the background signal increases due to unspecifically bound immunoglobulins

Engineering Contradiction:
Improvedetection sensitivityVSAvoidbackground signal
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (excess unlabeled class-specific antibody) that competes with the labeled detection antibody for binding sites on unspecifically bound immunoglobulins. This intermediary blocks the harmful background signal while allowing the labeled antibody to detect specifically bound antigen-antibody complexes, thus resolving the contradiction between detection sensitivity and background signal

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter of antibody concentration by adding excess unlabeled class-specific antibody to the detection mixture. This parameter change shifts the binding equilibrium away from unspecifically bound immunoglobulins (reducing background) while maintaining detection of specifically bound complexes (preserving sensitivity)

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the solid phase is modified to prevent unspecific binding, then the background signal is reduced, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvebackground signalVSAvoidsolid phase modification complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the problem of unspecific binding from the solid phase and transfers it to the detection reagent system. Instead of modifying the solid phase to prevent unspecific binding, the solution uses a chemical approach (excess unlabeled antibody) to selectively suppress background signals, thereby avoiding complex solid phase modifications while achieving the same effect

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses an unlabeled copy (unlabeled class-specific antibody) of the detection antibody to perform the blocking function. This unlabeled copy competes for binding sites on unspecifically bound immunoglobulins, preventing the labeled antibody from binding and creating background signal, thus solving the problem without modifying the solid phase

Inventive Principle:
Principle #26Copying

3Object-generated harmful factors

If buffer additives are used to reduce unspecific binding, then the background signal decreases, but the effectiveness varies across different tests and may reduce antibody reactivity

Engineering Contradiction:
Improvebackground signalVSAvoidtest format compatibility
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal solution (excess unlabeled class-specific antibody) that functions across all test formats and antibody types on the array. This single approach blocks unspecific binding for all immunoglobulin classes simultaneously without affecting antibody reactivity, making it adaptable to all tests on the array platform unlike format-specific buffer additives

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances the sensitivity and specificity of antigen-specific antibody detection in immunoassays by significantly reducing background signals, allowing for more reliable and consistent results across various tests on an array format, even in highly sensitive assays like the TSH test.

Implementation Method 1

B2 specifically binds antibodies of a certain immunoglobulin class which have been bound in an antigen-specific manner

Methodology Applied
Scientific EffectAntigen-antibody binding:

Implementation Method 2

B2 specifically binds antibodies of a certain immunoglobulin class which have been bound in an antigen-specific manner... B2 preferably recognizes the antigen-specific antibodies of the immunoassay in an array format which are bound more densely on the spot whereas immunoglobulins which are bound unspecifically to the solid phase, are not detected or only to a negligible extent

Methodology Applied
Scientific EffectSelective binding based on density:

Data Source

PatentUS8664007B2Immune complex-specific antibodies for increased sensitivity in immunoassay array tests
Publication Date: 2014.03.04 ROCHE DIAGNOSTICS OPERATIONS INC

AI summary

The invention concerns a method for determining antigen-specific antibodies of a particular immunoglobulin class in a sample by means of an immunoassay in an array format in which various binding partners Bnx are bound on different discrete areas on a support where Bnx in each case contain the various antigens that are able to specifically bind to the antibodies to be detected, by incubating the support with the sample and a binding partner B2 which carries a label and subsequently detecting the label on the respective discrete areas wherein B2 specifically binds antibodies of a certain immunoglobulin class that have been bound in an antigen-specific manner.