Lateral Flow Molecule Detection With Dual Test-Line Referencing
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Solution Overview
Problem
Existing lateral flow tests (LFTs) face challenges with saturation and resolution issues, leading to inaccurate quantification of target analytes, especially for small molecules, and are prone to errors due to antibody deterioration and ambient light interference, limiting their sensitivity and accuracy.
Innovation Solution
A lateral flow test device with a pre-loaded detectable conjugated analyte and two test regions, where the conjugated analyte can bind to both regions, allowing for a ratio-based calculation of target analyte concentration by comparing signal intensities between the regions, reducing errors and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional lateral flow test uses a single test line with immobilised capture molecules, then the device structure is simple, but the quantification accuracy deteriorates due to saturation and ambient light interference
Solution Approach 1:
The test device is segmented into two distinct test lines: a first test line with immobilised capture molecules for specific analyte detection, and a second test line with identical capture molecules serving as a reference. This segmentation allows separate measurement functions - one for specific detection and one for reference comparison - thereby improving quantification accuracy while maintaining relatively simple device structure
Solution Approach 2:
The second test line acts as an intermediary reference element that captures ambient light interference and systematic errors. By comparing the signal from the first test line (specific detection) with the signal from the second test line (reference), the ratio calculation eliminates common errors, improving measurement precision without adding complex processing systems
2Adaptability or versatility
If a lateral flow test uses competitive assay format for small molecules, then the assay can detect small molecules with single binding sites, but the sensitivity deteriorates due to inverse signal relationship
Solution Approach 1:
Instead of using the conventional competitive assay where analyte presence causes signal decrease (inverse relationship), this invention uses a ratio-based approach where the second test line provides a reference signal. The ratio of first test line signal to second test line signal directly correlates with analyte concentration, inverting the conventional inverse relationship into a direct relationship that improves sensitivity and measurement precision
3Measurement precision
If a lateral flow test uses sandwich assay format, then the detection accuracy is improved for large analytes, but the applicability deteriorates because it cannot detect small molecules
Solution Approach 1:
The test device is designed with universal capture molecules that can be selected based on the target analyte. By using the same basic structure (two test lines with capture molecules) for both sandwich and competitive assay formats, the device achieves multi-functionality - it can detect both large molecules (using sandwich format with detectable conjugate) and small molecules (using competitive format without detectable conjugate), thereby improving versatility while maintaining detection accuracy
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 device provides more accurate quantification of target analytes by inversely relating signal intensities between the two test regions, reducing systemic and ambient light-induced errors, and enabling precise concentration calculations.
Implementation Method 1
The sample is applied onto a sample pad, dissolves the deposited conjugate and migrates along the membrane by capillary action
Data Source
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AI summary
There is disclosed a lateral flow test device in which a conjugate pad comprises a mobilisable conjugated analyte comprising one or more analyte molecules conjugated to a detectable label. A first test region comprises an immobilised analyte-binding molecule defining a first binding site, or the conjugate pad comprises a mobilisable analyte-binding molecule and the first test region comprises an immobilised capture molecule for immobilising the analyte-binding molecule, wherein the immobilised capture molecule defines a first binding site, or the conjugate pad comprises a mobilisable analyte-binding molecule and the first test region comprises an immobilised analyte-binding molecule defining a first binding site. A second test region comprises an immobilised conjugated-analyte-binding molecule which binds the conjugated analyte and does not bind unconjugated analyte molecules, and defines a second binding site. The number of molecules of the conjugated analyte is less than or equal to the number of second binding sites. There is also disclosed methods of detecting the presence of an analyte molecule in a test sample and of diagnosing a disease or condition, a computer-implemented method of detecting the presence of an analyte molecule in a test sample, and a kit.