Multistep Lateral Flow Device with Rim-Pressed Matrix
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Solution Overview
Problem
Existing lateral flow capillary devices are limited in performing multistep reactions due to issues such as uneven sample distribution, liquid mixing, and structural limitations, which affect the accuracy and repeatability of results, especially when used outside laboratory settings.
Innovation Solution
A lateral flow capillary device with a unipath bibulous capillary flow matrix and multiple reservoirs, where each reservoir contacts a respective liquid receiving zone through a hollow conduit with rims that press the matrix, constraining liquid-induced swelling and preventing leakage, allowing for sequential addition of reagents and formation of static liquid-liquid interfaces without mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple reagents are added sequentially to perform multistep reactions, then reaction accuracy and repeatability improve, but liquid mixing and leakage occur due to matrix swelling
Solution Approach 1:
The device divides the capillary flow matrix into multiple separate liquid receiving zones, each isolated from the others. This segmentation prevents liquid mixing between different reagent addition steps while allowing sequential processing, directly resolving the contradiction between reliable multistep reactions and liquid mixing prevention.
Solution Approach 2:
A hydrophobic membrane is introduced as an intermediary layer between the reservoir and the capillary flow matrix. This membrane acts as a barrier that prevents direct contact and mixing between liquids while still allowing capillary flow to occur, enabling sequential reagent addition without cross-contamination.
2Stability of the object's composition
If sample is allowed to spread evenly in all directions, then sample distribution appears uniform, but sample and analyte are wasted due to distribution throughout entire matrix volume
Solution Approach 1:
The liquid receiving zone is designed with a unipath capillary flow structure that segments the flow path into a single direction rather than allowing radial diffusion. This ensures sample moves systematically through the matrix without spreading in all directions, maintaining composition stability while preventing sample waste.
Solution Approach 2:
The capillary flow matrix is designed with specific local properties at the liquid receiving zone that control sample flow direction and concentration. The local structure ensures sample is transported efficiently to the reaction zone without diffuse distribution throughout the entire matrix, optimizing both uniformity and resource utilization.
3Object-generated harmful factors
If hydrophobic spacers are used to prevent liquid mixing, then liquid separation improves, but spacers detach during storage
Solution Approach 1:
The hydrophobic membrane serves as a permanent intermediary structure that is integrated into the device architecture rather than being a detachable spacer. This membrane provides continuous liquid separation without requiring mechanical attachment, eliminating the detachment problem while maintaining liquid mixing prevention.
Solution Approach 2:
The mechanical spacer system is replaced with a hydrophobic membrane barrier that relies on surface chemistry rather than mechanical attachment. This substitution eliminates the attachment reliability issue by using a chemically-based separation mechanism that is inherently stable during storage and use.
4Device complexity
If sample is added through a single reservoir, then device complexity is reduced, but multistep reactions cannot be performed accurately
Solution Approach 1:
The single reservoir is segmented into multiple liquid receiving zones within the capillary flow matrix, each capable of receiving different reagents. This internal segmentation allows multistep reactions to occur with high accuracy while maintaining a simple external reservoir structure, resolving the contradiction between device simplicity and reaction capability.
Solution Approach 2:
The device transitions from a single-point sample addition to a distributed multi-zone structure within the same reservoir footprint. By utilizing the two-dimensional plane of the capillary flow matrix to create multiple receiving zones, the device achieves multistep reaction capability without increasing external complexity.
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 accurate and repeatable multistep reactions, even by less skilled operators, by ensuring precise control over reagent volumes and reaction durations, preventing leakage, and maintaining the integrity of capillary flow, thus enhancing the reliability of results in non-laboratory conditions.
Implementation Method 1
Sample 12 including the analyte bound to the labeled reagent, migrates by capillary flow to fill all of capillary flow matrix 18 and to migrate further into liquid drain 23
Implementation Method 2
a portion of the capillary flow matrix between the two rims is an interface creation zone
Data Source
AI summary
Disclosed is a lateral flow capillary device and uses thereof comprising a unipath bibulous capillary flow matrix and at least two reservoirs each in fluid communication with the capillary flow matrix wherein a reservoir contacts the capillary flow matrix through a passage having a rim pressing the matrix. The pressure that the rim applies on the matrix prevents leakage of liquids out of the capillary flow matrix at the reservoir/matrix interface, allowing accurate sequential draining of liquid from the reservoirs. During use of the disclosed lateral flow capillary device a static interface is formed between the first liquid and the second liquid in an interface creation zone inside the capillary flow matrix wherein the first amount and second amount are such that first liquid substantially remains in the first reservoir and the second liquid substantially remains in the second reservoir subsequent to the formation of the static interface and wherein the interface begins to move only subsequent to exhaustion of a liquid from a reservoir.