Capillary Microfluidic Device for Autonomous Sequential Flow
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Solution Overview
Problem
Conventional capillary microfluidic devices require external pumping and valving systems to manage the flow of liquids, which increases complexity and reduces portability, especially for point-of-care biomedical and food safety applications where sequential and controlled flow of different solutions is necessary.
Innovation Solution
A miniaturized capillary-based microfluidic device with multiple inlets and a microfabricated channel that utilizes capillary forces for autonomous and sequential delivery of liquids, preventing mixing through entrapped air or controlled microfluidic structures, eliminating the need for external pumping and valving systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external pumping and valving systems are used to manage liquid flow, then flow control precision is improved, but device complexity increases
Solution Approach 1:
The microfluidic device uses capillary forces generated by the microfabricated structures themselves to drive and control liquid flow, eliminating the need for external pumping systems. The structures serve both as flow channels and as the driving force mechanism.
Solution Approach 2:
The patent replaces mechanical pumping and valving systems with capillary forces arising from surface tension and wettability differences in the microfabricated structures, substituting a complex mechanical system with a passive physical phenomenon.
2Ease of operation
If external pumping and valving systems are used, then sequential flow control is improved, but portability is reduced
Solution Approach 1:
The device autonomously controls sequential liquid flow through capillary forces generated by its own microfabricated structures, requiring no external power sources or control systems, thereby enabling portable deployment.
Solution Approach 2:
External mechanical pumping and valving systems are replaced with passive capillary flow control mechanisms integrated into the microfabricated structures, eliminating heavy equipment while maintaining sequential flow capability.
3Productivity
If multiple liquids are delivered sequentially without separation, then flow efficiency is improved, but mixing occurs
Solution Approach 1:
Air bubbles are intentionally introduced as intermediary elements between different liquid samples in the queue, acting as physical barriers that prevent mixing while allowing continuous sequential flow through the microfluidic channel.
Solution Approach 2:
Air is extracted from the liquid samples and deliberately placed between them to create separation, transforming a typically unwanted element (air bubbles) into a useful separator that maintains sample integrity during sequential delivery.
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 device achieves controlled and sequential flow of liquids with high precision, reducing complexity and enhancing portability, making it suitable for point-of-care devices in biomedical and food safety applications.
Implementation Method 1
a specific volume of liquid placed in the respective first and second inlets flows autonomously such that the liquid in the first inlet flows into the microfluidic channel by capillary forces
Data Source
AI summary
Aspects of the present disclosure relate to a capillary fluidic device comprising at least two inlets, a microfluidic channel and an outlet. The device allows for the autonomous and programmable sequential flow of the same or different fluids using capillary fluidics for autonomous pumping of liquids to other downstream fluidic structures. External pumping and valving systems are not required, thus reducing complexity and increasing portability of stand-alone microfluidic systems. Aspects of the present disclosure can be applied to other fluidic structures for performing analytical biological assays. The integration has at least one reaction chamber and at least one capillary pump. The device is integrated with at least one sensor for detection and quantification of the biological assay signals.