Microfluidic Oxygenation Device with Passive Mixing Elements
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Solution Overview
Problem
Current blood oxygenation systems are limited by laminar blood flow, which restricts oxygenation to only the proximity of the permeable membrane, resulting in inefficient oxygen transfer to red blood cells, especially in devices without passive mixing elements.
Innovation Solution
A microfluidic oxygenation device with passive mixing elements on one wall of the flow channel, fabricated within a polymer substrate, that induces non-laminar flow patterns, such as chaotic or rotational flow, to enhance oxygen diffusion across the permeable membrane, allowing for more efficient oxygenation of blood over a shorter channel length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laminar blood flow is maintained in the oxygenation device, then the device structure is simple and easy to manufacture, but oxygenation efficiency is limited because only red blood cells near the permeable membrane can be oxygenated
Solution Approach 1:
The flow channel is segmented into multiple regions by introducing passive mixing elements (ridges, posts, or baffles) that divide the laminar flow into smaller flow patterns. This segmentation increases the surface area of the permeable membrane exposed to blood flow and creates multiple oxygenation zones, thereby improving oxygenation efficiency without requiring a completely complex device structure
Solution Approach 2:
Passive mixing elements are introduced into the two-dimensional laminar flow channel to create three-dimensional flow patterns. These elements generate rotational or chaotic flow that moves red blood cells from the center of the channel toward the permeable membrane surface, adding a vertical dimension to oxygen transfer and significantly enhancing oxygenation efficiency
2Volume of moving object
If the channel length is reduced to decrease priming volume, then the device size and priming volume are reduced, but oxygenation efficiency decreases because there is insufficient contact time between blood and oxygen
Solution Approach 1:
The device introduces dynamic flow patterns within the shortened channel by incorporating passive mixing elements that create rotational or chaotic flow. This dynamic flow increases the contact between blood and the permeable membrane surface, compensating for the reduced channel length and maintaining effective oxygenation despite the smaller priming volume
Solution Approach 2:
Passive mixing elements create periodic flow patterns that repeatedly bring red blood cells into contact with the permeable membrane surface. This periodic action ensures sufficient oxygen transfer occurs within the shortened channel residence time, maintaining oxygenation efficiency while reducing the required channel length and priming volume
3Productivity
If passive mixing elements are added to create non-laminar flow, then oxygen diffusion is enhanced and oxygenation efficiency increases, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The passive mixing elements are designed as simple geometric structures (ridges, posts, or baffles) that can be integrated into the flow channel using standard microfabrication techniques. These elements create non-laminar flow patterns that enhance oxygen diffusion without requiring complex porous materials or multi-step manufacturing processes
Solution Approach 2:
The mixing elements are designed with specific geometric parameters (height, width, spacing) that can be optimized to achieve the desired flow patterns. By carefully selecting these parameters, effective mixing is achieved while maintaining compatibility with standard fabrication processes and minimizing manufacturing complexity
4Area of stationary object
If the membrane surface area is reduced to decrease device size, then the device footprint is reduced, but oxygenation capacity decreases due to less surface area for gas exchange
Solution Approach 1:
Dynamic flow patterns created by passive mixing elements increase the effective utilization of the membrane surface area by continuously bringing fresh blood into contact with the membrane. This dynamic interaction allows for reduced physical membrane area while maintaining oxygenation capacity, as the same membrane surface is more effectively utilized over time
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
The device achieves more efficient oxygenation of blood by creating non-laminar flow patterns that increase the exposure of red blood cells to oxygen, reducing the required channel length and priming volume, while avoiding mechanical trauma to the blood cells.
Implementation Method 1
induces non-laminar flow patterns, such as chaotic or rotational flow
Implementation Method 2
enhance oxygen diffusion across the permeable membrane
Implementation Method 3
oxygenation of blood by pumping oxygen through an inner, hollow fiber pumping blood though a larger, outer fiber that encapsulates the inner fiber. The walls of the inner fiber are permeable to oxygen
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
A device and method for oxygenating blood is disclosed herein. The device includes a plurality of passive mixing elements that causes a fluid to mix as it flows through the device. The passive mixing elements continually expose new red blood cells to the portion of the flow channel where oxygenation can occur. Accordingly, in some implementations, the device and method uses less blood to prime the device and allows for the oxygenation of blood with a substantial shorter flow channel when compared to conventional oxygenation methods and devices.