Microfluidic Test Card with Capillary Valves for Autonomous Diagnostics
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Solution Overview
Problem
Current point-of-care diagnostic solutions for sample analysis are limited by high costs, complexity, and the need for laboratory equipment, failing to meet the ASSURED criteria for accessibility and simplicity, especially in low-resource settings.
Innovation Solution
A microfluidic test card system with capillary-driven fluidic operations and a lens-free holographic microscope for autonomous sample processing and analysis, enabling compact, cost-effective, and user-friendly diagnostics without the need for skilled professionals or laboratory equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If centralized laboratory equipment is used for diagnostic testing, then measurement precision and reliability are improved, but device complexity and cost increase, and accessibility decreases
Solution Approach 1:
The system divides the diagnostic testing function into two segments: a disposable microfluidic test card for sample processing and a simple reader device for detection. This segmentation allows the complex sample manipulation to be pre-packaged in a low-cost disposable unit, while the reader remains simple and accessible.
Solution Approach 2:
The microfluidic test card is designed as a disposable, low-cost component that performs all complex sample processing functions. After use, it is discarded, eliminating the need for expensive, maintainable equipment while maintaining diagnostic accuracy through pre-engineered fluidic operations.
2Ease of operation
If rapid diagnostic tests with nitrocellulose wicks are used, then ease of operation and accessibility are improved, but measurement precision and reliability deteriorate due to inability to perform quality controls
Solution Approach 1:
The microfluidic test card performs all sample processing operations autonomously through pre-engineered capillary channels and valves. The system self-regulates fluid flow, mixing, and reagent delivery without user intervention, ensuring consistent quality control while maintaining simplicity.
Solution Approach 2:
The system changes the fluid actuation mechanism from passive capillary wicking to controlled capillary valves that can be triggered to open or close. This allows precise control over fluid flow parameters, enabling reliable sample processing and quality control operations.
3Measurement precision
If molecular testing systems with complex cartridges and instruments are used, then measurement precision is improved, but device complexity and cost increase, and ease of operation decreases
Solution Approach 1:
The system separates the complex molecular testing functions into a pre-packaged disposable test card that contains all reagents, channels, and processing logic. The user simply applies the sample and the pre-programmed capillary valves execute the testing protocol automatically, eliminating the need for complex instrument operation.
Solution Approach 2:
All complex sample processing operations are pre-engineered into the test card during manufacturing. The capillary channels and valves are pre-configured to perform mixing, incubation, and separation operations in the correct sequence, so the user does not need to perform these complex steps manually.
4Volume of moving object
If miniaturized molecular testing instruments are used, then device size is reduced, but device complexity and cost increase due to mechanical, thermal and optical interfaces
Solution Approach 1:
The system replaces mechanical, thermal, and optical actuation interfaces with a purely capillary-based fluid control system. Capillary forces naturally drive fluid flow through the microchannels, eliminating the need for pumps, heaters, or optical actuators, thereby reducing device complexity and cost.
Solution Approach 2:
The capillary microfluidic system is self-actuating, using surface tension and capillary pressure to drive fluid flow, mixing, and separation operations. This self-service mechanism eliminates the need for external mechanical, thermal, or optical interfaces, enabling true miniaturization without 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
The system allows for efficient, autonomous sample processing and analysis, providing accurate results at a lower cost and increased accessibility, suitable for point-of-care diagnostics in resource-limited settings, as demonstrated by successful blood analysis performance.
Implementation Method 1
Fluid actuation occurs by capillary wicking of aqueous liquids in the nitrocellulose strips
Implementation Method 2
lens-free holographic microscope for autonomous sample processing and analysis
Data Source
AI summary
There is provided a device for analysis of sample liquid, the device comprising a microfluidic test card, and a microfluidic chip for processing the sample liquid presented from the microfluidic test card and return processed sample fluid to the microfluidic test card. The microfluidic test card comprises a sample inlet, configured for receiving sample liquid, first and second pre-processing test reagent channels having first and second test reagent outlets, respectively, for presenting test reagent to the microfluidic chip, a pre-processing sample channel fluidically communicating with the sample inlet for receiving sample liquid therefrom, and having a sample liquid outlet for presenting the sample liquid to the microfluidic chip, first and second processed sample analysis channels for receiving processed sample liquid from the microfluidic chip, wherein the first and the second processed sample analysis channels comprising a first and second analysis zone, respectively, for analysing the processed sample liquid, and a microfluidic chip contacting zone comprising said sample liquid outlet and first and second test reagent outlets, configured for connection and fluidic communication with the microfluidic chip.