Centrifugal Microfluidic Device Plasma Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing continuous flow microfluidic systems are not well-suited for handling high hematocrit-level whole blood samples, requiring dilution and longer processing times, and lack efficient methods for large-volume plasma separation.
Innovation Solution
A centrifugal microfluidic device with a polycarbonate substrate and multiple layers, featuring a sedimentation chamber with finger-like structures and a siphon channel, capable of separating plasma from whole blood samples up to 2 mL, using controlled rotational speeds to achieve high purity plasma collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If continuous flow microfluidic systems are used for blood sample processing, then the device can process large volume samples, but the systems require dilution of high hematocrit samples and have longer processing times
Solution Approach 1:
The device dynamically adjusts rotational speed through multiple phases: initial high speed for sedimentation, then reduced speed for plasma transfer. This dynamic operation enables the system to handle large volume samples (2-5 mL) while maintaining short processing time (20 seconds) by optimizing fluid movement at different operational stages
Solution Approach 2:
The system changes the rotational speed parameter from high (for sedimentation) to low (for transfer) to achieve different separation objectives. This parameter change allows efficient processing of large volume samples without requiring dilution, as the high-speed centrifugal force effectively separates plasma from cellular components in undiluted high hematocrit samples
2Quantity of substance
If continuous flow microfluidic systems are used, then large volume samples can be processed, but dilution with buffer is required for high hematocrit samples
Solution Approach 1:
The device extracts plasma from whole blood through centrifugal separation without requiring prior dilution. The sedimentation chamber separates plasma from cellular components, and the siphon channel extracts the plasma layer, eliminating the need for buffer dilution steps and reducing sample preparation complexity
Solution Approach 2:
The system performs self-service separation where the centrifugal force automatically separates plasma from blood cells based on density differences. The siphon channel autonomously transfers plasma when the interface reaches it, eliminating the need for external intervention or complex sample preparation protocols
3Extent of automation
If centrifugal microfluidic devices are used for plasma separation, then automation and miniaturization are achieved, but handling large volume samples (2 mL or more) is challenging
Solution Approach 1:
The device transitions from planar microfluidic channels to a three-dimensional sedimentation chamber with vertical plasma transfer. The siphon channel creates a vertical meniscus that rises and falls with plasma accumulation, utilizing the vertical dimension to handle large sample volumes while maintaining automation and compact footprint
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 efficiently separates plasma from whole blood with high purity (>99%) in less than half the time of commercial methods, automating the process and eliminating the need for manual pipetting, while maintaining the integrity of the plasma sample.
Implementation Method 1
By exploiting density and size differences between the various blood components, one sediments the denser cellular components of blood and is left with a cell-free plasma sample
Implementation Method 2
The sedimentation chamber and the collection chamber may be connected by a siphon channel
Data Source
AI summary
A CD-based device for separating plasma from whole blood includes a substrate, a sedimentation chamber disposed in the substrate, and a collection chamber disposed in the substrate and in fluidic communication with the sedimentation chamber through a siphon channel. The sedimentation chamber includes a plurality of finger-like structures disposed along a radially outward edge of the sedimentation chamber, and protruding radially inward relative to the axis of rotation of the substrate. A method for separating plasma from whole blood using the CD-based device includes introducing a blood sample into the sedimentation chamber, rotating the substrate about an axis of rotation at a first rotational speed to separate the plasma from blood cells, and rotating the substrate about the axis of rotation at a second rotational speed, which is lower than the first rotational speed, to move the plasma from the sedimentation chamber into the collection chamber.