Integrated Test Strip for Rapid Enzyme Inhibitor Detection
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Solution Overview
Problem
Current methods for detecting acetylcholinesterase inhibitors, such as pesticides and nerve agents, are complex, require multiple steps and equipment, and are not suitable for rapid on-site testing due to the need for standard curves, fluid transfer pipetting, and refrigeration of heat-labile reagents, making them inefficient for field use.
Innovation Solution
A modular, rapid test device in the form of a test strip with a sample pad and an enzyme substrate pad connected by a porous fluid transfer membrane, allowing for a single device with fewer reagents and steps, enabling detection of enzyme inhibitors through a measurable signal such as fluorescence or color without the need for oxidation or refrigeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If colorimetric methods using Ellman's reagent are used for detection, then measurement precision is improved, but device complexity increases due to multiple reaction vessels and fluid transfer steps
Solution Approach 1:
The patent combines multiple separate reagents (enzyme, substrate, indicator) and multiple reaction vessels into a single integrated test strip device. The test strip contains all necessary components arranged in sequence, eliminating the need for multiple pipetting steps and reaction vessels while maintaining detection accuracy through the integrated design.
Solution Approach 2:
The test strip is divided into distinct functional zones: a sample application area, an enzyme reaction zone, a substrate zone, and a detection zone. This segmentation allows each component to perform its specific function independently while being integrated into a single device, simplifying the overall procedure.
2Measurement precision
If standard curves and multiple pipetting steps are required, then measurement precision is improved, but loss of time increases due to numerous操作步骤
Solution Approach 1:
The test strip is pre-loaded with fixed, optimized amounts of enzyme and substrate in their respective zones during manufacturing. This preliminary preparation eliminates the need for time-consuming pipetting steps and standard curve preparation during actual testing, while maintaining quantitative accuracy through controlled reagent loading.
Solution Approach 2:
The test strip automatically controls the reaction process as sample fluid flows through the zones by capillary action. The pre-loaded reagents self-mix and react in the correct sequence without requiring operator intervention for timing or volume control, significantly reducing testing time while preserving measurement accuracy.
3Measurement precision
If heat-labile reagents are used, then measurement precision is improved, but ease of operation worsens due to refrigeration requirements
Solution Approach 1:
The patent changes the physical state of heat-labile reagents from liquid to dried form on the test strip. Drying the enzyme and substrate on the strip matrix stabilizes them at ambient temperature, eliminating refrigeration requirements while preserving their biological activity and measurement accuracy when rehydrated by sample fluid.
4Measurement precision
If oxidation pretreatment is required for organophosphate detection, then measurement precision is improved, but device complexity increases due to additional reagents and steps
Solution Approach 1:
The patent extracts and eliminates the oxidation pretreatment step from the detection procedure. By using an enzyme-based assay that directly detects organophosphate inhibition of acetylcholinesterase activity, the method bypasses the need for chemical oxidation and quenching steps, simplifying the procedure 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 solution allows for simplified, rapid detection of enzyme inhibitors in various samples, reducing the complexity and time required for testing, and eliminating the need for oxidation and refrigeration, making it suitable for on-site use.
Implementation Method 1
a porous fluid transfer membrane which runs the length of the device to enable fluid to travel from one end to the other
Implementation Method 2
The enzyme substrate directly or indirectly generates a detectable and measurable signal, such as, fluorescence or color, on reaction with the enzyme
Data Source
AI summary
A device and method for the rapid on-site detection of inhibitors of enzymes, such as acetylcholinesterase, is described wherein the device contains all reagents added to a sample pad containing dried releasable enzyme creating a reaction mixture wherein inhibitor deactivates the enzyme, while said reaction mixture travels via a longitudinal membrane to a distal porous pad containing a substrate for the enzyme. The reaction of the enzyme and the substrate results in a product that can generate a measurable signal such as color, fluorescence or luminescence to serve as a reporter. Signal that is generated at this reaction zone is inversely proportional to inhibitor concentration in the test sample. A device containing two such strips, one for a test sample, the other for a negative control fluid as an onboard comparator is described. A purpose-built reader or an illuminating device, such as, containing an incandescent light source, a diode, a UV light source or any other illumination source that is suitable for the reporter or mere visualization is used to determine the level of reporter.