Quantitative Assay Device with Calibration Bands
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Solution Overview
Problem
Existing assay devices for biological fluid samples often provide only qualitative results or rough quantitative measurements, suffering from inaccuracies due to temperature, moisture, flow time variations, and strip-to-strip inconsistencies.
Innovation Solution
A solid phase chromatographic assay device with microporous test strip membranes containing standard bands with immobilized calibrator agents, allowing for accurate concentration measurement of analytes by comparing label intensity in sample and standard bands, using gold sol conjugates and optical readers for precise quantification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard test strips with visual labels are used for analyte detection, then qualitative results can be obtained quickly, but measurement precision deteriorates due to temperature, moisture, and flow time variations
Solution Approach 1:
The test strip is divided into multiple discrete zones including sample application zone, test zone with capture antibodies, control zone with control antibodies, and calibration zones with known analyte concentrations. This segmentation allows simultaneous qualitative and quantitative analysis by comparing signal intensities across zones, resolving the contradiction between speed and precision.
Solution Approach 2:
The invention uses calibration zones with known analyte concentrations to establish a reference signal intensity range. By comparing the test zone signal to this calibrated reference, the system compensates for variations in temperature, moisture, and flow time, thereby maintaining measurement precision while preserving rapid detection capability.
2Ease of operation
If simple visual label formation is used in test strips, then device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to strip-to-strip variations
Solution Approach 1:
The test strip incorporates built-in calibration zones with known analyte concentrations that automatically provide reference signals for quantification. The strip self-calibrates by comparing test zone signals to calibration zone signals, eliminating the need for external calibration equipment and maintaining precision without complicating user operation.
Solution Approach 2:
The test strip integrates multiple functional components including capture antibodies, control antibodies, calibration analytes, and visual labels into a single composite structure. This composite design enables both qualitative detection and quantitative measurement with high precision while maintaining ease of use through a single integrated device.
3Measurement precision
If larger sample volumes are used for analysis, then measurement precision improves through better signal detection, but loss of substance increases due to sample consumption
Solution Approach 1:
The test strip concentrates the analyte detection function in a localized test zone with high-density capture antibodies and visual labels. This local concentration of detection capability maximizes signal intensity and measurement precision while requiring only minimal sample volume to achieve accurate results.
Solution Approach 2:
The test strip uses porous membrane materials that enable efficient capillary flow and concentration of analytes within the test zone. The porous structure increases the effective surface area for analyte capture and signal generation, improving detection sensitivity without increasing sample volume requirements.
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 rapid, efficient, and accurate quantitative analysis of fluid samples with low background noise, capable of detecting and quantifying analytes in small volumes, including blood, urine, and oils, while minimizing strip-to-strip variability.
Implementation Method 1
The test strip allows the label-bound analyte to move by capillary action to a sample capture zone
Implementation Method 2
the analyte complex is retained by virtue of being bound to the immobilized capture ligand
Implementation Method 3
In the case of a gold label the presence of the analyte is indicated by color formation at the analyte test zone
Implementation Method 4
Labels such as prepared from a gold sol are bound to a ligand capable of further binding or conjugating to an analyte
Data Source
AI summary
The present invention related to a quantitative assay device and a method for the determination of an analyte, based on a test strip, which contains a porous test membrane allowing for capillary flow of the analyte and complexes of the analyte, a porous upstream membrane in fluid connection with the test membrane and a porous downstream membrane in fluid connection with the test membrane, wherein the test membrane contains two bands having deposited on there high and low concentrations of different calibrator agents and a test band capable of reacting with conjugated analyte complexes giving rise to a measurable signal.