Multiplexed Lateral Flow Assay Fluid Distributor Pad
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Solution Overview
Problem
Current rapid diagnostic testing methods, particularly lateral flow assays, face challenges in efficiently distributing and managing sample fluid across multiple assays, leading to uneven test results and potential contamination, especially when testing for multiple analytes simultaneously.
Innovation Solution
A multiplexed lateral flow device with an impermeable internal reservoir and a fluid distributor pad featuring a pattern of hydrophobic material to evenly distribute the sample among multiple flow paths, combined with an impermeable top and bottom cover and a spacer element to isolate assays and prevent contamination, allowing for simultaneous testing of multiple analytes from a single sample deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single sample is used for multiple lateral flow assays, then testing efficiency and productivity are improved, but sample distribution uniformity and measurement precision deteriorate
Solution Approach 1:
The sample pad is segmented into multiple distinct flow paths using hydrophobic barriers (wax lines) that divide the sample deposition area into separate channels. Each channel directs sample fluid to a specific lateral flow assay, ensuring uniform distribution while enabling simultaneous multiplexed testing.
Solution Approach 2:
Different regions of the sample pad are given different properties through hydrophobic material deposition. The hydrophobic barriers create localized fluid routing patterns that guide sample flow to specific assays, while hydrophilic regions facilitate uniform wicking. This local differentiation ensures each assay receives equal sample volume.
2Area of stationary object
If multiple lateral flow assays are arranged closely to save space, then device area is reduced, but contamination risk between assays increases
Solution Approach 1:
Hydrophobic barrier materials (wax lines) are introduced as intermediary elements between adjacent lateral flow assays. These barriers act as fluid repellent walls that prevent cross-contamination by blocking lateral fluid migration, while allowing the assays to be positioned in close proximity for compact device design.
Solution Approach 2:
Thin hydrophobic film barriers are deposited on the sample pad to create impermeable boundaries between flow paths. These thin film structures provide effective contamination prevention without adding significant bulk or space requirements, enabling compact assay arrangement.
3Quantity of substance
If sample volume is increased to ensure sufficient fluid for all assays, then sample adequacy is improved, but device complexity and fluid management difficulty increase
Solution Approach 1:
The sample pad is divided into multiple flow paths from the beginning, creating separate channels that each receive a predetermined portion of the sample. This segmentation allows a smaller total sample volume to be efficiently distributed to multiple assays, as each path independently wicks sample away rather than requiring all assays to compete for the same fluid pool.
Solution Approach 2:
The hydrophobic barrier pattern on the sample pad creates self-directed fluid routing that automatically distributes sample to appropriate assays without external control. The sample fluid naturally follows the hydrophilic pathways defined by the hydrophobic barriers, eliminating the need for complex pumping or valve systems to manage fluid distribution.
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 ensures uniform distribution of the sample across multiple assays, reducing contamination risks and enabling simultaneous testing for multiple analytes, such as HIV, syphilis, and tuberculosis, with improved reliability and accuracy of test results.
Implementation Method 1
a paper based microfluidic element having a pattern of a hydrophobic material to distribute the sample deposition substantially equally among the plurality of flow paths
Implementation Method 2
the internal reservoir is configured to receive a sample volume of a liquid, and to retain decreasing portions of the sample volume over a predetermined range of time equal to or greater than a time during which the liquid is being wicked into the fluid distributor pad
Data Source
AI summary
A multiplexed lateral flow device includes an impermeable internal reservoir having an opening to receive a sample deposition. A fluid distributor pad is arranged in fluid communication with a lower surface of the internal reservoir. The fluid distributor pad includes a paper based microfluidic element having a pattern of a hydrophobic material to distribute a portion of the sample deposition substantially equally among a plurality of flow paths. Lateral flow assays having a plurality of flow lines are aligned with flow paths of the distributor pad. An impermeable top cover has a first window arranged over the opening of the internal reservoir, and at least a second window arranged over the test results of the lateral flow assays. A housing element houses the reservoir, the distributor pad and lateral flow assays. The housing element includes an impermeable bottom cover and a spacer element arranged between the top and bottom covers and, provides a gap between the lateral flow assays and the impermeable top cover.