Membrane Carrier Microstructure for POCT Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Point of Care Test (POCT) reagents using immunochromatography face challenges in achieving both high sensitivity and short detection times due to variations in flow rate, which affect the uniformity of the flow-path structure, leading to inconsistent test results.
Innovation Solution
A membrane carrier with a microstructure that changes along the flow path, featuring convex portions with specific shapes and dimensions, is used to control the flow rate of the liquid sample, ensuring a ratio of highest to lowest flow rate between 1.0 and 10, and both flow rates are maintained between 0.30 mm/s and 5.0 mm/s, enhancing capillary action and reducing determination time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nitrocellulose membrane with natural micropores is used, then the structure is simple and easy to manufacture, but the flow rate varies depending on the membrane leading to inconsistent test results
Solution Approach 1:
The patent uses a porous polyethylene terephthalate membrane as the base material, maintaining the simplicity of porous structure manufacturing while providing more uniform pore characteristics compared to natural nitrocellulose membranes. The porous structure allows liquid sample passage while the controlled pore distribution ensures consistent flow rates.
Solution Approach 2:
The patent introduces microstructures with specific geometric parameters (convex portions having controlled height, width, and spacing) to modify the flow path characteristics. By changing the physical parameters of the flow path through these microstructures, the flow rate is standardized across different membranes while maintaining ease of manufacture through replication of the microstructure pattern.
2Measurement precision
If the flow rate is decreased to increase sensitivity, then the detection sensitivity improves, but the determination time becomes long
Solution Approach 1:
The patent divides the flow path into multiple segments by introducing periodic convex microstructures. This segmentation creates multiple capillary action zones along the flow path, allowing the liquid sample to be propelled forward in stages. The segmented structure enables optimization of flow velocity in different regions, maintaining high sensitivity through adequate residence time while reducing overall determination time through enhanced capillary driving force in each segment.
Solution Approach 2:
The patent optimizes the geometric parameters of the convex microstructures (height, width, spacing) to control the capillary pressure and flow rate. By carefully selecting these parameters, the flow rate is adjusted to a range that provides sufficient residence time for target-substance binding (maintaining sensitivity) while preventing excessive determination time. The parameter optimization balances the trade-off between sensitivity and speed.
3Reliability
If a uniform flow-path structure is created, then the flow rate becomes consistent, but the structure cannot satisfy varying functional requirements in different portions of the flow path
Solution Approach 1:
The patent applies the local quality principle by making the microstructure parameters (height, width, spacing of convex portions) vary at different positions along the flow path. This allows different regions of the flow path to have optimized characteristics for their specific functions: some regions promote faster flow, while others provide longer residence time for binding reactions. The periodic variation in microstructure parameters enables both flow rate consistency and functional adaptability.
Solution Approach 2:
The patent introduces dynamic characteristics to the flow path structure by creating periodic variations in the microstructure along the flow direction. This dynamic structure allows the flow path to adapt its characteristics at different positions, enabling the system to provide both consistent overall flow rate control and localized functional optimization for different test requirements.
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 enables highly sensitive and rapid detection of target substances, optimizing the balance between sensitivity and time, thereby improving the reliability of POCT results.
Implementation Method 1
a microstructure producing capillary action for transporting the liquid sample is formed at a bottom of the flow path
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The present invention provides a membrane carrier 3 for a test kit of detecting a target substance in a liquid sample, comprising at least one flow path 2 transporting the liquid sample, wherein a microstructure producing capillary action for transporting the liquid sample is formed at a bottom of the flow path 2, and the microstructure is provided to change along a transport direction d of the liquid sample.