Membrane Strip Sensor Using Swellable Expansion Member for Sequential Reactions
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Solution Overview
Problem
Conventional immunochromatographic assays face challenges in achieving high sensitivity and requiring multiple reaction steps with a single sample injection, limiting their ability to perform complex biological reactions like enzyme-antibody reactions and chemiluminescent reactions effectively.
Innovation Solution
A membrane strip sensor design incorporating a water-soluble plastic tape as a swellable member, which allows a secondary reagent to contact a reaction membrane after sample injection, enabling sequential reactions without additional reagent injection, using a primary reagent on a conjugate pad and a secondary reagent pad with signal-generating substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional immunochromatographic assay is used, then the structure is simple and manufacturing is easy, but multiple reaction steps cannot be performed with a single sample injection and detection sensitivity is limited
Solution Approach 1:
The device is divided into distinct functional modules: a first reagent pad containing primary reagents, a second reagent pad containing secondary reagents, and a reaction membrane. These segments are arranged in sequence to enable multiple reaction steps (antigen-antibody reaction followed by enzyme reaction) within a single test strip, resolving the contradiction between versatility and complexity.
Solution Approach 2:
The first and second reagent pads are pre-loaded with reagents before use. When sample is injected, the reactions occur automatically in sequence without requiring additional manual intervention. This preliminary preparation enables complex multi-step reactions to be performed seamlessly, enhancing adaptability while maintaining ease of operation.
2Measurement precision
If multiple reaction steps are implemented, then detection sensitivity improves, but the number of reagent injections required increases
Solution Approach 1:
Multiple reagent delivery functions are merged into a single sample injection process. The sample liquid serves as the driving force to sequentially activate both the first reagent pad and second reagent pad, enabling multiple reaction steps (including enzyme reactions and chemiluminescence) to occur without additional injections, thus improving detection sensitivity while maintaining operational simplicity.
Solution Approach 2:
The reaction membrane acts as an intermediary that facilitates the sequential interaction between sample, primary reagents, and secondary reagents. It enables the sample to traverse through different reaction zones in sequence, allowing multiple reaction steps to occur with a single injection, thereby resolving the contradiction between measurement precision and ease of operation.
3Productivity
If reagent pads are placed in direct contact, then reaction efficiency is high, but reagent cross-contamination occurs
Solution Approach 1:
The first reagent pad and second reagent pad are nested in a sequential arrangement along the sample flow path, with the reaction membrane positioned between them. This nested structure allows the sample to sequentially access both reagent pads without direct contact between the pads themselves, maintaining reaction efficiency while preventing reagent cross-contamination through the reaction membrane barrier.
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 the execution of multiple reaction steps, such as enzyme and antigen-antibody reactions, with high detection sensitivity through a single sample injection, expanding the application range and maintaining a simple, cost-effective production process.
Implementation Method 1
the swellable portion swells by the liquid sample contained in the sample pad
Implementation Method 2
The assay strip performs the immunoassay by moving the liquid specimen from the specimen pad 40 through the signal detecting pad 20 to the absorption pad 50
Data Source
AI summary
A membrane strip sensor according to an embodiment of the present disclosure, the membrane strip sensor includes: a support; a sample pad; a conjugate pad; a reaction membrane; a absorption pad; and a secondary reagent pad.