Dual-Assay Device for Extended Analyte Range
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Solution Overview
Problem
Existing assay devices face limitations in measuring analyte levels over an extended concentration range due to the 'hook effect' and signal depletion at high analyte concentrations, particularly in sandwich immunoassays, and cross-binding issues between detection zones, which affect precision and sensitivity.
Innovation Solution
The implementation of a dual-assay system with separate flow-paths and detection zones, each capable of indicating analyte levels in distinct concentration ranges, using immobilized and mobilizable binding reagents to prevent cross-binding and extend the dynamic range of measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sandwich immunoassay is used to detect analyte, then the assay can detect analyte presence, but the signal plateaus or decreases at high analyte levels due to the hook effect
Solution Approach 1:
The assay device is divided into multiple independent detection zones (first detection zone and second detection zone) with different binding reagents having different affinities for the analyte. Each zone operates independently to detect different concentration ranges, segmenting the single-assay system into multiple functional units that collectively extend the measurable range.
Solution Approach 2:
Different detection zones are designed with locally optimized properties - the first detection zone uses binding reagents with higher affinity for low-concentration analyte detection, while the second detection zone uses binding reagents with lower affinity for high-concentration analyte detection. This local differentiation of binding characteristics allows each zone to function optimally within its specific concentration range.
2Adaptability or versatility
If multiple detection zones are provided on the same porous carrier, then the device can detect analyte at different concentrations, but cross-binding occurs between zones affecting precision
Solution Approach 1:
The assay device is divided into multiple independent detection zones (first detection zone and second detection zone) with different binding reagents having different affinities for the analyte. Each zone operates independently to detect different concentration ranges, segmenting the single-assay system into multiple functional units that collectively extend the measurable range.
Solution Approach 2:
A flow separator is introduced as an intermediary component between the sample application and the detection zones. This flow separator directs the sample flow to ensure that binding reagents from different zones do not mix or cross-bind, while still allowing both zones to receive sample for independent analysis. The flow separator physically mediates the interaction between zones to prevent cross-contamination.
3Device complexity
If a single assay system is used to measure extended analyte range, then the device structure remains simple, but signal depletion occurs at high analyte concentrations
Solution Approach 1:
The assay device is divided into multiple independent detection zones (first detection zone and second detection zone) with different binding reagents having different affinities for the analyte. Each zone operates independently to detect different concentration ranges, segmenting the single-assay system into multiple functional units that collectively extend the measurable range.
Solution Approach 2:
The binding reagents in different detection zones are designed with different affinity parameters for the analyte. The first detection zone uses reagents with higher affinity optimized for low-concentration detection, while the second detection zone uses reagents with lower affinity optimized for high-concentration detection. This parameter differentiation allows the system to maintain reliable signal intensity across extended concentration ranges without depletion.
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 accurate measurement of analyte levels across a broader range without signal reduction, improving precision and sensitivity by isolating binding reagents and using scavenger reagents to manage analyte binding, thereby overcoming the limitations of single-assay systems.
Implementation Method 1
a porous carrier comprising a dried mobilisable labelled binding reagent
Implementation Method 2
a first binding reagent which binds a detection probe to generate a detection signal having an intensity proportional to the amount of analyte
Data Source
AI summary
Disclosed is an assay device for the determination of the presence and/or extent if an analyte in a liquid sample over an extended concentration range comprising a first assay and a second assay, wherein the first assay for an analyte comprises a first flow-path having a sole detection zone capable of immobilizing a labelled binding reagent and the second assay for said analyte comprises a second flow-path having a sole detection zone capable of immobilizing a labelled binding reagent, wherein the presence of labelled binding reagent at the detection zones provides an indication of the presence and/or extent of analyte in said liquid sample.