Microfluidic Device Backflow Prevention for CTC Separation
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Solution Overview
Problem
Conventional microfluidic devices face challenges in handling large volumes of blood for circulating tumor cell separation due to backflow issues, which lead to contamination and inaccurate results.
Innovation Solution
A microfluidic device with a backflow prevention unit that includes a moisture absorbent in a second chamber, positioned to absorb filtered fluid in a direction opposite to centrifugal force, and features such as angled micro flow channels and non-permeable walls to prevent fluid backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large volume microfluidic device is designed to handle several milliliters of blood for CTC separation, then the separation capacity is improved, but the filtered blood can backflow and contaminate the filtration membrane
Solution Approach 1:
A hydrophobic porous membrane is introduced as an intermediary component between the first chamber and second chamber. This membrane allows air to pass through but blocks liquid blood from backflowing into the filtration chamber, thus preventing contamination while maintaining the ability to handle large blood volumes for CTC separation
Solution Approach 2:
The patent applies different material properties to different parts of the device: the filtration membrane has specific pore sizes for CTC separation, while the backflow prevention membrane is specifically made hydrophobic to block liquid backflow. This localized differentiation of material properties solves both the large-volume handling and backflow prevention requirements
2Productivity
If the microfluidic device is designed with a large filtration chamber to process several milliliters of blood, then the CTC separation efficiency is improved, but the device complexity increases
Solution Approach 1:
The device is segmented into distinct functional chambers: a first chamber for blood loading, a filtration chamber for CTC separation, and a second chamber for waste collection. This segmentation allows each chamber to be optimized for its specific function while maintaining overall system simplicity
Solution Approach 2:
The backflow prevention function is extracted as a separate component (the hydrophobic porous membrane) rather than being integrated into the main filtration structure. This extraction simplifies the overall device design by isolating the backflow prevention mechanism from the filtration process
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
Effectively prevents backflow and contamination, allowing for efficient handling and filtration of larger blood volumes, thereby improving the accuracy of circulating tumor cell separation.
Implementation Method 1
a moisture absorbent positioned in the second chamber and capable of absorbing a filtered fluid
Implementation Method 2
The second chamber may have a shape having at least one end portion protruding toward a center of the body, and include the moisture absorbent in the end portion of the second chamber such that a moisture absorption is possible in a direction opposite to a centrifugal force
Data Source
Figure 1~1(b)
Figure 2
Figure 3~3(d)
AI summary
The present invention may provide a microfluidic device including a rotatable body; a first chamber positioned in a direction of an inner wall of the body; a second chamber positioned in a direction of an outer wall of the body from the first chamber; and a backflow prevention unit, and wherein a fluid is transferred from the first chamber to the second chamber, and wherein the backflow prevention unit prevents a backflow of the fluid from the second chamber to the first chamber.