Assay Device Multiple Reagent Cells Wider Plume
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Solution Overview
Problem
Lateral flow assay devices face challenges with reduced signal due to narrow reagent plumes and inefficient use of smaller sample sizes, particularly when conjugate material is deposited in the center of the conjugate zone and dissolved from the sides, leading to inadequate mixing and reduced sensitivity.
Innovation Solution
The assay device incorporates multiple reagent cells in the reagent zone, arranged to experience identical flow conditions, with flow control elements that combine multiple flow streams into fewer streams, creating a wider reagent plume and enhancing mixing with the sample, which is then directed into the detection zone for improved signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conjugate material is deposited in the center of the conjugate zone and dissolved from the sides, then the device structure is simple, but the reagent plume remains narrow and mixing with sample is inefficient
Solution Approach 1:
The conjugate zone is divided into multiple reagent cells (first, second, and third reagent cells) arranged in parallel. Each cell receives sample flow and generates a separate reagent plume. This segmentation transforms a single narrow plume into multiple plumes that can be combined, increasing overall plume width and improving sample mixing efficiency without significantly increasing device complexity.
2Measurement precision
If multiple reagent cells are used to widen the reagent plume, then sensitivity and signal strength improve, but device complexity increases
Solution Approach 1:
Multiple reagent cells are merged in parallel configuration within the conjugate zone, with their output streams combining to form a wider reagent plume. The flow control elements guide and merge the flows from individual reagent cells, achieving enhanced plume width and sensitivity while maintaining a relatively compact device structure through efficient spatial arrangement.
3Ease of operation
If sample size is reduced for easier collection, then ease of operation improves, but reagent mixing efficiency and signal strength decrease
Solution Approach 1:
The sample flow is segmented into multiple streams that pass through separate reagent cells in parallel. This segmentation allows each small sample portion to be efficiently mixed with reagent in its dedicated cell, and the combined output from multiple cells creates a wider, better-mixed reagent plume that maintains signal strength even when total sample volume is reduced.
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 results in a more desirably mixed, wider reagent plume in the detection zone, increasing signal strength and sensitivity, even with smaller sample sizes, and allows for efficient use of the sample, improving the overall performance of the assay device.
Implementation Method 1
They employ a porous material, e.g., nitrocellulose, defining a path for fluid flow capable of supporting capillary flow
Implementation Method 2
The sample-addition zone frequently consists of a more porous material, capable of absorbing the sample, and, when separation of blood cells is desired, also effective to trap the red blood cells
Implementation Method 3
the detection zone having substrate and projections which extend vertically from the substrate, wherein the projections have a height, cross-section and a distance between one another that defines a capillary space between the projections capable of generating capillary flow parallel to the substrate surface
Data Source
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AI summary
An assay device includes: a liquid sample zone; a reagent zone downstream and in fluid communication with the sample zone. The reagent zone includes at least two reagent cells containing a reagent material and arranged in the reagent zone such that each reagent cell experiences substantially the same flow conditions of sample from the sample zone. The reagent cells divide the sample flow from the sample zone into multiple flow streams. Also included are: one or more flow control elements disposed downstream from the reagent zone which combine the multiple flow streams into fewer flow streams; a detection zone in fluid communication with the reagent zone; and a wicking zone in fluid communication with the detection zone having a capacity to receive liquid sample flowing from the detection zone. The sample addition zone, the detection zone and the wicking zone define a fluid flow path.