Microfluidic Device Reference Liquid Flow Blocking
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Solution Overview
Problem
Microfluidic devices for agglutination and coagulation tests face inaccuracies due to incomplete stopping of sample flow, requiring a narrow time frame for examination, which complicates the testing process.
Innovation Solution
A microfluidic device design featuring a test channel and a reference channel with a merging region and common downstream channel section, where the reference liquid blocks the test liquid flow at the merging point, ensuring complete cessation of flow and enhancing test accuracy by maintaining a consistent flow until the reference liquid reaches the common downstream channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the device uses a capillary pathway with reagent system to detect agglutination, then the test can detect analyte presence through viscosity changes, but the sample flow never stops completely leading to high inaccuracy
Solution Approach 1:
A reference liquid is introduced as an intermediary substance to block the capillary pathway. This reference liquid serves as a mediator that physically stops the test sample flow by occupying the capillary pathway, enabling complete flow cessation for accurate endpoint detection.
Solution Approach 2:
The reference liquid is applied in advance to the capillary pathway before the test sample is introduced. This preliminary action ensures that when the test sample flows through, it will be completely blocked by the pre-positioned reference liquid, guaranteeing flow stopping completeness.
2Device complexity
If the sample flow is allowed to continue until natural deceleration, then the device structure remains simple, but the examination must be performed within a narrow time frame
Solution Approach 1:
The reference liquid acts as a timing mechanism by blocking the capillary pathway at a controlled point. This allows the test to be completed at a predetermined time point rather than relying on natural flow deceleration, extending the acceptable examination time frame without increasing device complexity.
3Reliability
If the reference liquid blocks the test liquid flow at the merging region, then complete flow cessation is achieved, but air bubble capture risk increases
Solution Approach 1:
The device incorporates localized air vent channels at specific positions where air bubbles can escape. These vent channels are strategically positioned to allow air bubble removal at critical points in the fluid path, particularly where the reference liquid blocks the test liquid flow, thereby reducing air bubble capture risk while maintaining flow cessation completeness.
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 improves the reliability and simplicity of microfluidic testing by ensuring accurate detection of property changes in samples, allowing for more flexible examination times and reducing the risk of air bubble capture, thereby enhancing the precision and usability of the device.
Implementation Method 1
The microfluidic device comprises a test channel comprising an upper test channel section with an upstream end and a sampling region at its upstream end and at least one reference channel comprising an upper reference channel section with an upstream end and a sampling region at its upstream end... a reference liquid flowing from the upper reference channel section into the merging region will block a test liquid flow in the upper test channel section
Data Source
AI summary
A microfluidic device comprising at least one test channel, which test channel comprises an upper test channel section with an upstream end and a sampling region at its upstream end and at least one reference channel, which reference channel comprises an upper reference channel section with an upstream end and a sampling region at its upstream end. The test channel and the reference channel comprise a merging region downstream to the upper test channel section and a common downstream channel section. The merging region and the common downstream channel section are arranged such that a reference liquid flowing from the upper reference channel section into the merging region will block a test liquid flow in the upper test channel section when the test liquid flow has not yet reached the merging section. The microfluid device may be used for detecting change of flow properties e.g. due to agglomeration, agglutination or viscosity change in a liquid preferably selected from water, urine, blood, or blood plasma.