One-Step IgG Immunoassay Using Multivalent Bridge Antigen
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Solution Overview
Problem
Current methods for detecting antigen-specific antibodies, particularly IgG, in a one-step format are inadequate as they fail to distinguish between free and bound analytes, and often require monomeric antigens, which are not always available, leading to interference from unspecific IgG and inability to differentiate between IgG and IgM antibodies.
Innovation Solution
A method involving a first analyte-specific receptor with multiple binding sites and a second receptor that selectively binds to arrangements of analyte molecules, allowing for the detection of antigen-specific antibodies without washing steps, using rheumatoid factor-like antibodies that preferentially bind aggregated IgG, thus distinguishing between free and bound analytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a one-step test format is used for antibody detection, then the productivity and ease of operation are improved, but the ability to distinguish between free and bound analytes deteriorates
Solution Approach 1:
The patent introduces a bridge molecule (antigen) that mediates between the captured antibody and the detection antibody. The bridge antigen is specifically designed to bind to epitopes on the heavy chain of IgG, enabling selective detection of IgG class antibodies in a one-step format without washing steps, thus resolving the contradiction between test speed and detection specificity
Solution Approach 2:
The patent changes the binding parameters by using antibodies with different specificities: the capture antibody binds to the Fc region of IgG, while the detection antibody binds to the Fab region. This parameter change enables class-specific detection (IgG vs IgM) in a one-step format by exploiting the structural differences between immunoglobulin classes
2Measurement precision
If monomeric antigens are used, then the ability to selectively detect IgG is improved, but the adaptability deteriorates due to limited availability
Solution Approach 1:
The patent segments the antigen into multiple copies attached to a carrier molecule, creating a multivalent antigen structure. This segmentation allows the antigen to simultaneously bind multiple antibodies, enabling selective detection of IgG through the formation of sandwich complexes while maintaining versatility in antigen source selection
3Measurement precision
If washing steps are included, then the measurement precision is improved by removing unspecific IgG, but the productivity deteriorates
Solution Approach 1:
The patent implements a continuous one-step reaction format where capture, binding, and detection occur simultaneously in a single well without interruption for washing. The reaction mixture remains continuous throughout the assay, allowing automated systems to process samples rapidly while maintaining precision through the specific bridge antigen design
4Measurement precision
If class-specific antibodies are used for detection, then the measurement precision is improved, but the device complexity increases due to multiple reagents required
Solution Approach 1:
The patent creates a universal detection system where the bridge antigen serves multiple functions: it captures the analyte antibody, provides class-specific discrimination through heavy chain binding, and enables signal generation. This multi-functional bridge molecule simplifies the overall reagent requirements while maintaining high measurement precision for antibody class discrimination
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
Enables sensitive and specific detection of antigen-specific IgG antibodies in a one-step format, even in the presence of other immunoglobulin classes and excess non-specific IgG, without signal loss, facilitating early detection in infectious diseases and autoimmune diagnostics.
Implementation Method 1
contacting the sample with a first analyte-specific receptor and a second analyte-specific receptor wherein one of the two receptors is bound to a solid phase or is capable of binding to a solid phase
Implementation Method 2
the other receptor carries a signal-generating group or is capable of binding to a signal-generating group
Implementation Method 3
using rheumatoid factor-like antibodies that preferentially bind aggregated IgG, thus distinguishing between free and bound analytes
Data Source
AI summary
Methods for determining an analyte in a sample by immunoassay in a one-step format without performing washing steps are described. The method includes a first analyte-specific receptor that contains at least two binding sites for the analyte, and a second analyte-specific receptor that selectively binds to an aggregate arrangement of at least two analyte molecules bound to the first receptor.