Microfluidic Device Pressure Control Inlet Outlet Circuit
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Solution Overview
Problem
Microfluidic devices face challenges in achieving repeatable and controlled flows due to issues like parasitic flow caused by bubbles, high hydrodynamic resistance, and sensitivity to surface charge variations, especially when handling biological molecules.
Innovation Solution
A microfluidic device design that uses an inlet and outlet circuit connected to a chamber, allowing pressure control at one end of the microchannel independently, enabling precise flow regulation and minimizing gas entry into the microchannel to prevent bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microvalves are incorporated into the microfluidic device to avoid parasitic flow, then parasitic flow is reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes the microvalve component entirely from the microfluidic device. Instead of incorporating complex microvalves to control parasitic flow, the invention uses a simple microchannel opening that allows parasitic flow to be extracted or vented externally, thereby eliminating the reliability issue without adding device complexity
Solution Approach 2:
The patent introduces an intermediary element - a microchannel opening connected to an external environment - that mediates the parasitic flow issue. This opening serves as a mediator that allows controlled release of parasitic flows without requiring complex internal valve mechanisms
2Volume of moving object
If microchannels with small cross section are used to reduce device size, then device miniaturization is achieved, but hydrodynamic resistance increases
Solution Approach 1:
The patent addresses the hydrodynamic resistance issue by transitioning to a three-dimensional microchannel structure. Instead of relying solely on planar two-dimensional channels, the invention incorporates vertical dimensionality with channels extending through the thickness of the device, effectively increasing the flow cross-sectional area and reducing hydrodynamic resistance while maintaining device miniaturization
3Ease of operation
If electric field electroosmosis is used to impose controlled flow, then flow control is achieved, but the method is limited to conductive liquids and is sensitive to surface charge variations
Solution Approach 1:
The patent replaces the electric field-based electroosmosis mechanism with a mechanical pressure-driven flow control system. By using pressure differentials applied through microchannel openings and external pressure sources, the invention achieves flow control that is independent of liquid conductivity and surface charge properties, thereby expanding versatility to all liquid types
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 design achieves repeatable and controlled flows with reduced hydrodynamic loss, allowing for precise dynamic control and efficient operation, especially in handling small volumes and biological samples.
Implementation Method 1
an inlet circuit and an outlet circuit which are connected to the chamber and between which a flow of fluid can be established without contact with the microchannel, at least one of the inlet and outlet circuits being controllable so as to modify the pressure at said end of the microchannel
Implementation Method 2
using a liquid to transmit pressure from the chamber
Data Source
AI summary
The invention relates to a microfluidic device comprising at least one micro-channel connected at one end to an enclosed area, characterized in that it also comprises an inlet circuit and an outlet circuit connected to the enclosed area and between which the fluid can be discharged without any contact with the micro-channel, wherein at least one of said inlet and outlet circuits can be controlled in such a way that the pressure at the end of the micro-channel can be modified independently from the pressure at the other end of the micro-channel.