Microfluidic Fluid Transport via Pneumatic Pressure Source
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Solution Overview
Problem
Current microfluidic flow cell technologies face challenges in precisely and reliably transporting fluids while maintaining fluid tightness and reducing production costs, as they often rely on friction and capillary forces, which can lead to fluid detachment and contamination.
Innovation Solution
A device that applies pressure at the front end of the fluid to overcome flow resistance, using a pressure source connected to the microfluidic element, ensuring precise fluid transport and preventing contamination by sealing the system, and allowing for precise control and division of fluid quantities without the need for additional valves or hydrophilization coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If friction and capillary forces are used to transport fluid, then manufacturing effort is reduced, but fluid transport precision and reliability deteriorate due to fluid detachment and wetting-related advance or lag
Solution Approach 1:
The patent applies pneumatic pressure through a pressure source connected to the channel to transport the fluid plug. The pressure difference between the front and rear ends of the fluid plug enables controlled transport, replacing reliance on friction and capillary forces while maintaining manufacturing simplicity.
Solution Approach 2:
The patent changes the transport mechanism from passive friction/capillary forces to active pressure-driven flow by introducing a pressure source. This parameter change allows precise control of fluid transport while eliminating the need for complex coatings or high-precision microstructures.
2Device complexity
If friction and capillary forces are used to transport fluid, then device complexity is reduced, but reliability deteriorates due to unwanted detachment of small amounts of fluid and environmental contamination
Solution Approach 1:
The pressure source creates a pressure gradient that confines the fluid plug, preventing detachment at the front surface. The pressurized gas source maintains fluid containment without requiring complex sealing mechanisms or valves.
Solution Approach 2:
The patent applies pressure locally at the front and rear ends of the fluid plug to maintain containment. This localized pressure application prevents fluid detachment and contamination while keeping the overall device structure simple.
3Ease of operation
If a vent is connected to the upstream portion of the channel, then fluid transport is enabled, but fluid tightness deteriorates leading to environmental contamination
Solution Approach 1:
The patent replaces the vent connection with a pressure source connection that maintains positive pressure throughout the channel. This pneumatic approach enables fluid transport while keeping the system sealed, preventing environmental contamination.
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 solution enables precise and reliable fluid transport within microfluidic elements, preventing fluid detachment and contamination, reducing production costs, and allowing for efficient division and mixing of fluids, enhancing analytical and diagnostic processes.
Implementation Method 1
The pressure applied to the front end surface of the fluid, in particular to a front fluid meniscus, prevents unwanted detachment of small amounts of fluid from the end surface
Implementation Method 2
The pressurized liquid volume, which fills the channel like a plug, is forced through the channel against the flow resistance
Implementation Method 3
not only by overcoming resistance caused by friction and capillary forces
Implementation Method 4
overcoming resistance caused by friction and capillary forces
Data Source
Figure 1~2
Figure 3(a)~3(f)
Figure 4~8
AI summary
The invention relates to a device for transporting a fluid in a channel of a microfluidic element, in particular a flow cell. According to the invention, a pressure source is provided for pressurizing a front end surface (42) of the fluid, which completely fills the cross-section of the channel, in the direction of transport. Preferably, the pressure source comprises a closed space (17; 22; 34; 36, 38, 40) in which a pressurized gas, e.g., air, can be compressed by displacing the front end surface (42) of the fluid transported in the channel.