Fc-binding Molecule Signal Amplification in Immunoassays

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Solution Overview

Problem

Current immunoassays lack sufficient sensitivity for detecting antibodies, particularly for infectious agents, which hinders accurate and rapid diagnostic capabilities.

Innovation Solution

Incorporating detectable Fc-binding molecules such as Protein A or Protein G conjugates, either alone or in combination with other detectable entities, to enhance antibody detection in immunoassays by forming complexes with antibodies and amplifying signals in antigen-based capture or sandwich-type assays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional immunoassay methods are used, then the assay can be performed with simple procedures, but the sensitivity of antibody detection is insufficient

Engineering Contradiction:
Improvesensitivity of antibody detectionVSAvoidassay procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces Fc-binding molecules (Protein A or Protein G) as intermediary components that bind to the Fc region of antibodies. These molecules serve as mediators between the antibody and the detectable label, enabling signal amplification without fundamentally changing the basic immunoassay procedure. The Fc-binding molecules act as a bridge that allows multiple detectable labels to associate with each antibody, thereby increasing sensitivity while maintaining procedural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If Fc-binding molecules are added to amplify signals, then the sensitivity of detection increases, but the complexity of the assay increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidassay structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The Fc-binding molecules serve multiple functions simultaneously: they bind specifically to the Fc region of antibodies, provide attachment sites for detectable labels, and enable signal amplification. This multi-functionality allows a single component to address multiple requirements (specificity, detectability, and amplification) without requiring separate complex systems for each function.

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

3Measurement precision

If multiple detectable entities are used for signal amplification, then the detection limit is reduced, but the manufacturing complexity increases

Engineering Contradiction:
Improvedetection limitVSAvoidconjugate preparation complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The Fc-binding molecules naturally provide multiple binding sites that can simultaneously bind multiple detectable labels without requiring complex external assembly processes. The self-service principle is manifested in how the Fc-binding molecule's structure inherently enables multi-label attachment, reducing the need for complex manufacturing procedures to assemble the conjugates.

Inventive Principle:
Principle #25Self-service

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 use of Fc-binding molecules significantly increases the sensitivity of antibody detection, allowing for more accurate and rapid identification of antibodies in samples, even at low concentrations, thereby improving diagnostic efficiency.

Implementation Method 1

the addition of detectable Fc-binding molecules (e.g., Protein A- conjugates, Protein G-conjugates, secondary antibody conjugates) can be used for the detection of antibodies in immunoassays

Methodology Applied
Scientific EffectFc-binding:

Implementation Method 2

antibodies to be detected are captured by antibody-specific binding entities, e.g., antigens

Methodology Applied
Scientific EffectAntigen-antibody binding:

Data Source

PatentEP3489685B1Signal amplification in lateral flow and related immunoassays
Publication Date: 2023.11.01 ZOETIS SERVICES LLC
  • EP3489685B1 patent drawingFigure 1
  • EP3489685B1 patent drawingFigure 2
  • EP3489685B1 patent drawingFigure 3

AI summary

The present invention provides methods, devices, compositions (e.g., capture complexes), and kits useful for enhancing the detection of antibodies in a test sample. The methods, devices, and compositions utilize detectable Fc-binding molecules such as Protein A, Protein G, and/or an Fc-specific antibody to amplify the signal of a detected antibody in immunoassays, such as lateral flow assays.