Fluid Triggerable Valves Using Segmented Capillary Barriers
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Solution Overview
Problem
Existing microfluidic devices require complex geometries and expensive deep reactive ion etching for capillary pressure barriers, which compromise channel geometry and are sensitive to the order of fluid menisci arrival, leading to potential air entrapment issues.
Innovation Solution
A fluid triggerable valve design using two capillary pressure barriers spaced apart to pin and coalesce fluid menisci, reducing the pressure required for breaching and allowing controlled fluid flow, with optional stretching barriers to stabilize the menisci and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common pinning barrier is used to pin both menisci, then the valve can control fluid flow, but the channel geometry is compromised and complex deep reactive ion etching is required
Solution Approach 1:
The invention divides the single common pinning barrier into two separate pinning barriers positioned at different locations. Each barrier independently pins one meniscus, eliminating the need for complex z-direction patterning and deep reactive ion etching while maintaining effective fluid flow control through the two-meniscus mechanism.
2Manufacturing precision
If deep reactive ion etching is used to create pinning barriers, then precise geometry can be achieved, but the process is expensive and time-consuming
Solution Approach 1:
The separation of pinning barriers into two simple structures positioned at different locations allows for much simpler manufacturing. Instead of requiring deep reactive ion etching to create complex z-direction patterns in a single barrier, the segmented design enables easier fabrication through standard microfluidic manufacturing techniques.
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 valve design enables efficient and controlled fluid flow in microfluidic systems, reducing the need for complex geometries and expensive etching processes, while ensuring reliable operation and minimizing air entrapment.
Implementation Method 1
capillary pressure barriers for controlling or influencing the behaviour of fluids
Implementation Method 2
Two pinning barriers are provided in a microfluidic channel, spaced apart such that a first fluid-fluid meniscus is pinned on the first pinning barrier and a second fluid-fluid meniscus is pinned on the second pinning barrier
Implementation Method 3
Two pinning barriers are provided in a microfluidic channel, spaced apart such that a first fluid-fluid meniscus is pinned on the first pinning barrier and a second fluid-fluid meniscus is pinned on the second pinning barrier
Data Source
AI summary
The present invention relates to a fluid triggerable passive valve for controlling flow of one or more fluids comprising:a volume comprising at least two capillary pressure barriers for respectively pinning a first and second fluid-fluid meniscus,the two capillary pressure barriers dividing the volume in at least three sub volumes, whereby two sub volumes being positioned upstream and one sub volume being positioned downstream with respect to the advancement direction of each respective fluid-fluid meniscus;wherein the capillary pressure barriers are spaced apart such that upon pinning of a first fluid-fluid meniscus on a first capillary pressure barrier and arrival or pinning of a second fluid-fluid meniscus on or at a second capillary pressure barrier, the two menisci touch and thereby coalesce into one fluid-fluid meniscus.