Nested Sandwich Immunoassay for Low-Concentration Peptide Detection
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Solution Overview
Problem
Current immunoassays for detecting Aβ peptides, particularly Aβ40 and Aβ42, in plasma samples from sporadic Alzheimer's disease patients have insufficient sensitivity, with detection limits often exceeding the low concentrations found in these patients, making reliable diagnosis challenging.
Innovation Solution
A kit comprising specific antibodies and a binding pair system with a detectable tag is used to capture and quantify Aβ40 and Aβ42 peptides, enhancing sensitivity to detect levels below 0.1 pg/mL, allowing for reliable quantification in plasma samples from sporadic AD patients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional immunoassays are used to detect Aβ peptides in plasma, then the assay can be performed with standard methods, but the sensitivity is insufficient and detection limits exceed the low concentrations found in sporadic AD patients
Solution Approach 1:
The patent implements a nested sandwich immunoassay structure where the first antibody captures the Aβ peptide and the second antibody binds to a different epitope on the same peptide, creating a nested sandwich complex. This nested configuration allows for highly sensitive detection of low-concentration Aβ peptides in plasma samples from sporadic AD patients, achieving detection limits below the physiological concentrations present in these samples.
Solution Approach 2:
The patent optimizes multiple parameters including antibody concentrations, incubation times, washing stringency, and detection reagent concentrations to enhance assay sensitivity. By systematically adjusting these parameters, the assay achieves detection capabilities for Aβ peptides at concentrations as low as those found in plasma samples from sporadic AD patients, overcoming the sensitivity limitations of conventional methods.
2Measurement precision
If the detection limit is reduced to detect low concentrations of Aβ peptides, then sensitivity improves, but the complexity of the assay increases
Solution Approach 1:
The patent divides the detection process into distinct sequential steps: capture antibody binding, washing, detection antibody binding, and signal detection. Each step is optimized independently to contribute to overall sensitivity while maintaining manageable complexity. The segmentation of the sandwich assay into discrete steps allows for systematic optimization without overwhelming complexity.
Solution Approach 2:
The patent uses a solid support matrix as an intermediary to immobilize the capture antibody and facilitate the sandwich complex formation. This intermediary structure simplifies the assay by providing a stable platform for antibody-antigen interactions, enabling sensitive detection while maintaining procedural simplicity through standardized plate-based formats.
3Ease of operation
If standard immunoassay methods are used, then the procedure is simple and routine, but the detection limit is too high for reliable diagnosis in sporadic AD patients
Solution Approach 1:
The patent develops a universal sandwich immunoassay platform using monoclonal antibodies that can detect multiple forms of Aβ peptides (Aβ40, Aβ42, and oligomeric forms) in a single assay format. This multi-functional approach maintains operational simplicity by using a standardized protocol while achieving the sensitivity required for reliable diagnosis in sporadic AD patients through the enhanced specificity of monoclonal antibodies.
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 kit achieves high sensitivity in detecting Aβ40 and Aβ42 peptides, enabling reliable quantification in plasma samples from sporadic AD patients, overcoming the limitations of existing assays by providing a detection limit significantly lower than previous methods, thus facilitating early and accurate diagnosis.
Implementation Method 1
capturing the target polypeptide present in the sample with a first antibody or combination of antibodies which bind specifically said target polypeptide
Implementation Method 2
contacting the immune complexes formed in step (a) with a second antibody or combination of antibodies which recognise a different region of the target polypeptide
Data Source
AI summary
The invention relates to immunoassays which allow the detection of polypeptides in samples with a higher sensitivity than assays of the state of the art. The invention also relates to kits which provide the components needed for carrying out said immunoassays.