Assay Device Micro Flow Path Porous Medium Segmentation
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Solution Overview
Problem
Conventional paper-based assay devices face limitations in sensitivity, accuracy, and the ability to perform multistage assays due to low sensitivity, high variation, and the requirement for large sample amounts, making them unsuitable for quantitative analysis and difficult to use in scenarios like infant or young child testing.
Innovation Solution
The development of an assay device featuring a micro-lateral flow path with fluid-impervious members and an interposing member, where a porous medium is positioned near the distal end, allowing for a fluid-impervious space that enables high sensitivity, accuracy, and multistage assays without the need for external pumps or complex operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional paper-based assay devices are used, then the devices are simple and low-cost, but the sensitivity and measurement precision are low
Solution Approach 1:
The device is segmented into distinct functional zones: a micro-lateral flow path for liquid transport, a fluid-impervious space for reaction containment, and a porous medium for detection. This segmentation allows each component to perform its function optimally, improving measurement precision while maintaining overall device simplicity
Solution Approach 2:
A fluid-impervious space acts as an intermediary between the micro-lateral flow path and the porous medium. This intermediate space enables controlled liquid flow and reaction processes, enhancing sensitivity without requiring complex external control systems
2Adaptability or versatility
If conventional paper-based assay devices are used, then the devices do not require external pumps, but the ability to perform multistage assays is limited
Solution Approach 1:
The micro-lateral flow path and fluid-impervious space create a dynamic system where liquid flow can be controlled and directed through different stages. This dynamic structure enables multistage assays to be performed by simply adding reagents to the flow path without complex operational procedures
Solution Approach 2:
The device structure serves multiple functions: the micro-lateral flow path transports liquid, the fluid-impervious space contains reactions, and the porous medium performs detection. This multi-functionality enables various multistage assay protocols to be performed using the same device structure
3Quantity of substance
If conventional paper-based assay devices are used, then the devices use small sample amounts, but the sample amount required is still larger than ideal for infant or young child testing
Solution Approach 1:
The fluid-impervious space provides a localized reaction zone with controlled volume, allowing highly sensitive measurements to be performed with minimal sample amounts. This local containment of the reaction process enables accurate measurements even with the small sample volumes available from infant or young child testing
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 design enhances sensitivity and accuracy, allows for quantitative analysis, and enables continuous supply and cessation of multiple liquids, facilitating multistage assays with reduced sample requirements.
Implementation Method 1
these devices determine the presence or absence of the target substance according to the movement of the substance in the porous medium due to capillary phenomenon
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(f)
AI summary
The assay device (10) comprises a micro flow path (76); a porous medium provided near the distal end portion (80) of the micro flow path (76); and a space (82) provided between the micro flow path (76) and the porous medium for controlling the flow rate of a fluid moving from the micro flow path (76) to the space (82). After a fluid moved along the micro flow path (76) based on a lateral flow is brought into contact with the porous medium beyond the space (82) and is absorbed to the porous medium, the fluid is divided by the space (82) so that the fluid stays in the micro flow path (76). With this structure, it is possible to perform solution exchange in the micro flow path without using an external device such as a pump.