Capillary Fluid Delivery for Sequential Reagent Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lateral flow strip tests (LFTs) are limited by their simplicity to single-step chemical processes and lack control over assay conditions, restricting their sensitivity and analytical capabilities, while microfluidic systems are complex and costly due to the need for external pumps and valves for fluid manipulation.

Innovation Solution

The development of capillary-based devices that allow sequential delivery of multiple fluids to a porous receiving element without leakage, using ideal and non-ideal fluid sources to control fluid transport and reagent delivery, enabling more complex chemical processes on a microfluidic scale.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If lateral flow strip tests use simple wicking through porous membranes for fluid transport, then the device is simple and user-friendly, but control over assay conditions is limited and sensitivity is reduced

Engineering Contradiction:

Improveuser-friendlinessVSAvoidanalytical sensitivity

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The device is divided into multiple functional zones along the flow path, including separate sample application area, reagent zones, and detection areas. Each zone can be independently optimized for its specific function, allowing complex multi-step chemistries to be performed while maintaining overall device simplicity and ease of use.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the porous membrane are assigned different properties and functions. The membrane structure, porosity, and reagent loading are locally optimized for each zone's specific requirements, enabling precise control over fluid flow and chemical reactions at different locations while keeping the overall device simple.

Inventive Principle:

Principle #3Local quality

2Device complexity

If lateral flow assays are restricted to single-step detection chemistries, then the device remains simple and inexpensive, but sensitivity and analytical capabilities are limited

Engineering Contradiction:

Improveassay simplicityVSAvoiddetection sensitivity

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

Multiple reagents are pre-loaded in dried form at different locations on the strip. As fluid flows through the device, these reagents are sequentially activated and mixed, enabling multi-step chemical amplification and detection processes without requiring complex external instrumentation or multiple manual steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The device enables continuous multi-step chemical reactions to occur as fluid flows through different zones. Detection chemistries can proceed through multiple sequential steps including amplification, labeling, and readout generation, all occurring continuously within the single flowing sample stream, thereby enhancing sensitivity without increasing device complexity.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If microfluidic systems incorporate external pumps and valves for fluid manipulation, then control over fluid transport is improved, but manufacturing cost and device complexity increase

Engineering Contradiction:

Improvefluid control capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The porous membrane structure itself provides the fluid transport function through capillary action, eliminating the need for external pumps. The membrane's inherent properties (porosity, hydrophobicity/hydrophilicity patterns) automatically control fluid flow direction and rate, providing adaptability and control capability while maintaining device simplicity and reducing manufacturing cost.

Inventive Principle:

Principle #25Self-service

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 approach enhances the sensitivity and analytical capabilities of LFTs by allowing multi-step chemistries and improves the efficiency and cost-effectiveness of fluid processing, enabling precise control over fluid and reagent transport in microfluidic systems.

Implementation Method 1

fluid transport occurring due to the capillary pressure of the strip material

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

flow of fluid through the LFT usually occurs by wicking through a membrane

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

Capillarity provides the force needed to provide a nearly continuous flow of fluid

Methodology Applied

Scientific EffectCapillary pressure: Capillary Pressure

Data Source

PatentUS11098346B2Sequential delivery of fluid volumes and associated devices, systems and methods

Publication Date: 2021.08.24 UNIV OF WASHINGTON

AI summary

The present technology is directed to capillarity-based devices for performing chemical processes and associated system and methods. In one embodiment, for example, a device can include a porous receiving element having an input region and a receiving region, a first fluid source and a second fluid source positioned within the input region of the receiving element; wherein the first fluid source is positioned between the second fluid source and the receiving region, and wherein, when both the first and second fluid sources are in fluid connection with the input region, the device is configured to sequentially deliver the first fluid and the second fluid to the receiving region without leakage.