Electrically Activated Capillary Stop Valve Using Fluid Electrodes
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Solution Overview
Problem
Capillary stop valves in microfluidic devices are difficult to control and activate controllably, relying on passive control methods without moving mechanical parts, making it challenging to manage fluid flow effectively.
Innovation Solution
A microfluidic device that uses electrically isolated channels with conductive fluids acting as electrodes to apply an electrical potential difference, allowing for controlled activation of capillary stop valves without the need for metal layers, enabling fluid flow in various orientations and configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If passive capillary stop valves are used in microfluidic devices, then the device eliminates the need for bulky pumps and valves, but the valve becomes difficult to control and activate controllably
Solution Approach 1:
The patent replaces mechanical control systems with an electrical field-based activation mechanism. By applying an electrical potential difference between two conductive fluids separated by a dielectric layer, the system generates electrostatic forces that activate the capillary stop valve without requiring mechanical pumps, valves, or moving parts. This substitution enables controllable valve activation while maintaining the compact, pump-free design of passive capillary systems.
2Ease of operation
If conventional electrode activation methods are used with a second electrode spaced apart by an electrically insulating medium gap, then the capillary stop valve can be activated, but the device structure becomes more complex
Solution Approach 1:
The patent merges the electrode function with the fluid medium itself. Instead of using separate solid electrodes with insulating gaps, the system uses two conductive fluids that directly contact the capillary stop valve from opposite sides. The dielectric layer is integrated into the channel structure rather than being a separate component, simplifying the overall device architecture while maintaining effective electrical field generation for valve activation.
Solution Approach 2:
The patent uses fluids as the active medium for both fluid transport and electrical field generation. Conductive fluids serve dual purposes: they are the working fluid that flows through the microchannel and also act as electrodes when a potential difference is applied. This eliminates the need for separate solid electrode structures and integrates the activation mechanism into the fluid system itself.
3Use of energy by moving object
If metal layers are used for electrode fabrication, then electrical potential can be applied, but the manufacturing cost and fabrication complexity increase
Solution Approach 1:
The patent replaces solid metal electrode structures with conductive fluids that serve as electrodes. This eliminates the need for metal layer deposition, patterning, and fabrication processes associated with conventional electrode manufacturing. The conductive fluids are introduced through standard microfluidic filling procedures, significantly simplifying fabrication and reducing manufacturing costs while maintaining the ability to apply electrical potential for valve activation.
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 allows for controllable actuation of capillary stop valves, reducing activation voltage requirements and facilitating fluid mixing and flow management in both horizontal and vertical planes, while avoiding the complexity and cost of metal layers.
Implementation Method 1
Both the first fluid and the second fluid can then act as fluid electrodes to conduct electrical energy
Implementation Method 2
Microfluidic devices utilizing capillary action to promote fluid flow
Implementation Method 3
By applying an electric potential difference between the electrodes, the capillary stop valve is activated and the fluid flows down into another channel
Data Source
AI summary
A microfluidic device for electrically activating a passive capillary stop valve, an apparatus and method are provided. The microfluidic device includes a first channel for containing a first fluid, and an output channel, wherein the first channel comprises a first interface with the output channel, and the first interface comprises a capillary stop valve characterised in that the microfluidic device also comprises a second channel for containing a second fluid, wherein the second channel comprises a second interface with the output channel, and the first channel and the second channel are electrically isolated from each other, and the first interface and the second interface are arranged relative to each other thereby being configured to activate fluid flow from the first channel into the output channel when a first fluid and a second fluid are present, and an electrical potential difference is applied between the first fluid and the second fluid.