Resin Barrier in Immunochromatographic Test Piece for Reagent Stability
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Solution Overview
Problem
Immunochromatographic test pieces used for detecting group A β-hemolytic streptococcus face issues with reagent reaction and activity reduction due to contact between acid and neutralizing reagents during long-term preservation, leading to reduced sensitivity and inefficient antigen extraction.
Innovation Solution
A resin-made sheet, such as a PET sheet, is sandwiched between pads impregnated with acid reagents and neutralizing reagents to minimize contact and control the development speed and direction of the specimen, preventing premature reaction and maintaining reagent activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pads impregnated with acid reagent and neutralizing reagent are contacted and adhered to each other for long-term preservation, then the test piece can be stored compactly and conveniently, but the reagents react with each other progressively, reducing their respective activities and detection sensitivity
Solution Approach 1:
A resin-made sheet (such as PET sheet) is introduced as an intermediary barrier between the acid reagent pad and neutralizing reagent pad. This sheet prevents direct contact and reaction between the reagents during storage, while still allowing the test piece to be stored in a compact form. The resin sheet acts as a physical mediator that maintains reagent stability without compromising storage convenience.
Solution Approach 2:
The test piece is divided into separate functional zones with the acid reagent pad, neutralizing reagent pad, and resin-made sheet arranged in distinct segments. This segmentation allows each component to perform its function independently while preventing unwanted interactions between reagents during storage, yet enables compact assembly for convenient storage.
2Loss of time
If the acid reagent and neutralizing reagent are placed close together to shorten test duration, then the overall testing time is reduced, but the antigen extraction time becomes insufficient, reducing sensitivity performance
Solution Approach 1:
The resin-made sheet is designed with specific permeability characteristics that dynamically control the flow of liquid between pads. During the test, it allows sufficient liquid passage for antigen extraction while preventing backflow of neutralizing reagent to the acid reagent pad, thereby maintaining optimal extraction time without extending overall test duration.
Solution Approach 2:
Different regions of the test piece are designed with different properties: the resin-made sheet has controlled porosity and hydrophobicity in specific zones to regulate liquid flow locally. This ensures that the acid reagent zone maintains sufficient contact time with the specimen for effective antigen extraction, while other zones facilitate rapid processing.
3Speed
If the specimen flows rapidly from the acid reagent pad to the neutralizing reagent pad, then the test process is accelerated, but the mixing time between nitrite and acid reagent is insufficient, preventing adequate antigen extraction
Solution Approach 1:
The resin-made sheet functions as a flexible thin film that selectively controls liquid flow. It allows the specimen to pass through at an appropriate rate for adequate mixing and extraction, while preventing excessive rapid flow that would reduce extraction efficiency. The film's properties are tuned to achieve optimal flow control.
Solution Approach 2:
The test piece design incorporates hydraulic principles through the resin-made sheet's capillary action and flow resistance characteristics. The sheet creates controlled flow paths that regulate specimen movement speed, ensuring sufficient contact time between reagents and specimen for effective antigen extraction while maintaining overall test speed.
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 configuration improves long-term preservation stability, extends antigen extraction time, and enhances detection sensitivity by controlling the movement of reagents and specimens, ensuring efficient nitrous acid treatment.
Implementation Method 1
a resin-made sheet is sandwiched between the region impregnated with the solid acid reagent or the nitrite and the region impregnated with the neutralizing reagent so as to suppress the movement of a reagent or the movement of a specimen solution between the regions
Implementation Method 2
an antigen of group A β-hemolytic streptococcus is extracted with nitrous acid generated by mixing a nitrite solution with an acid solution
Implementation Method 3
an antibody-sugar chain antigen-labeled antibody complex is formed in the detection region to measure the sugar chain antigen
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
It is an object of the present invention to provide a method or an immunochromatographic test piece, which controls a speed or a direction of development of a specimen on the immunochromatographic test piece, so that a treatment with an acid reagent, nitrite, and a neutralizing reagent is properly controlled. The present invention provides an immunochromatographic test piece for extracting and measuring a sugar chain antigen in a specimen, the immunochromatographic test piece comprising: a sample pad to which a specimen mixed with nitrite or an acid solution is added; a label region comprising a labeled antibody obtained by labeling an antibody against the sugar chain antigen; and a detection region on which the antibody against the sugar chain antigen is immobilized, wherein an antibody-sugar chain antigen-labeled antibody complex is formed in the detection region to measure the sugar chain antigen, and the immunochromatographic test piece having a region impregnated with a neutralizing reagent upstream of the label region, and further having a region impregnated with a solid acid reagent when the specimen mixed with the nitrite is used, or a region impregnated with nitrite when the specimen mixed with the acid solution is used, upstream of the region impregnated with the neutralizing reagent, wherein a resin-made sheet is sandwiched between the region impregnated with the solid acid reagent or the nitrite and the region impregnated with the neutralizing reagent so as to suppress the movement of a reagent or the movement of a specimen solution between the regions.