Centrifugal Microfluidic Conduit Crest for Gas-Trapped Liquid Transfer
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Solution Overview
Problem
Centrifugal microfluidic devices face challenges in efficiently mixing and sequencing liquids while preventing gas escape during liquid transfer, often requiring rotation cessation for venting, which disrupts the process.
Innovation Solution
A centrifugal microfluidic device design with a conduit crest traps gas between liquids, controlling liquid flow by rotational frequency to vent gas at a controlled time, allowing continuous operation without stopping, and utilizing an unvented cavity to reduce rotation speed requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conduit without a crest is used, then liquid flow is simpler, but gas escapes through the liquid and vents into the upstream chamber, disrupting the process
Solution Approach 1:
The conduit is pre-configured with a crest (radially outward extension) before liquid transfer begins. This preliminary structural preparation creates a gas trap that prevents gas escape during subsequent liquid flow, eliminating the need for reactive gas management measures
Solution Approach 2:
The crest acts as an intermediary gas trap structure between the upstream and downstream chambers. It captures and holds gas that would otherwise escape through the liquid, mediating the interaction between liquids and gas phases during centrifugal transfer
2Productivity
If rotation is stopped to vent gas, then gas can be released, but continuous operation is disrupted and process efficiency decreases
Solution Approach 1:
The crest-enabled gas trapping mechanism allows the centrifugal device to maintain continuous rotation and liquid transfer operations without interruption. Gas is continuously trapped and managed within the crest structure, eliminating the need to stop rotation for venting and preserving productive continuous action
3Speed
If high rotational frequency is used to transfer liquid, then liquid transfer is efficient, but gas pressure increases and may cause uncontrolled venting
Solution Approach 1:
The crest structure converts the potentially harmful effect of increased gas pressure at high rotation speeds into a beneficial gas trapping mechanism. The pressure build-up that would cause uncontrolled venting is instead harnessed to seal gas within the crest, transforming a problem into a solution that enables efficient high-speed liquid transfer
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
Enables controlled mixing and sequencing of liquids with gas retention, facilitating continuous operation and reduced rotational frequency needs, enhancing process efficiency and flexibility.
Implementation Method 1
The liquid may be caused to flow through such a device under the action of centrifugal force, by rotating the device about an axis of rotation
Implementation Method 2
by configuring the first conduit to have a crest, the device is more robust than if the first conduit did not have a crest. In particular, gas is trapped in the crest. As a result, the trapped gas is radially inwards (in the crest) of the liquid either side of the gas and under the action of centrifugal force, the liquid is kept radially outwards of the gas
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A liquid handling device having an axis of rotation about which the device can be rotated to drive liquid flow in the device is provided. The device comprises an upstream chamber comprising an outlet, a downstream chamber comprising a proximal portion radially inwards of a distal portion and comprising a first port disposed in the distal portion and a first conduit which connects the outlet of the upstream chamber to the first port of the downstream chamber. The first conduit extends radially inwards to a crest and radially outwards from the crest to the first port of the downstream chamber. A distance between the axis of rotation and the crest is greater than or equal to a distance between the axis of rotation and the outlet of the upstream chamber.