Microfluidic Blood Separation via Gravitational Sedimentation
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Solution Overview
Problem
Current methods for separating blood plasma from whole blood, such as centrifugation, can damage red blood cells and require the use of lysing chemicals, which interfere with spectroscopic assays, and are difficult to automate and maintain sterility.
Innovation Solution
A microfluidic device with a channel that approximates patterns like circular, elliptical spirals or serpentine shapes, where whole blood is held to allow sedimentation, enabling the separation of plasma serum and cells without the need for centrifugation or lysing chemicals, using the difference in densities to separate the fractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If centrifugation is used to separate plasma from whole blood, then separation speed is improved, but red blood cells are damaged and lysing chemicals are required
Solution Approach 1:
The patent replaces the centrifugal mechanical separation system with a microfluidic device that uses controlled fluid flow and sedimentation. The microfluidic channel allows blood to flow slowly and settle under gravity, separating plasma from cells without the high-speed centrifugal forces that damage red blood cells.
Solution Approach 2:
The patent changes the separation parameters from high-speed centrifugal force to low-speed gravitational sedimentation in a microfluidic environment. By controlling flow rate and channel geometry, the system achieves separation based on density differences without the harmful mechanical stresses of centrifugation.
2Productivity
If centrifugation is used to separate plasma from whole blood, then separation efficiency is improved, but lysing chemicals are required which interfere with spectroscopic assays
Solution Approach 1:
The patent eliminates the need for chemical lysing by using microfluidic flow control to achieve complete cellular separation. The controlled laminar flow and sedimentation process in the microfluidic channel allows plasma to be collected without any cellular lysis, avoiding contamination with intracellular contents that would interfere with spectroscopic analysis.
Solution Approach 2:
The patent employs a disposable microfluidic device that performs separation in a single use, eliminating the need for chemical reagents like lysing buffers. The device is discarded after one use, ensuring no chemical contamination carries over to subsequent assays.
3Productivity
If traditional centrifugation methods are used, then separation capability is achieved, but automation difficulty increases and sterility maintenance becomes complex
Solution Approach 1:
The microfluidic device is designed to perform separation automatically through passive mechanisms. Blood enters the device and separation occurs automatically through controlled flow and sedimentation without requiring manual intervention for centrifugation setup, monitoring, or plasma collection, making the process inherently automatable.
Solution Approach 2:
The microfluidic device uses thin-film fabrication techniques to create integrated channels and structures that maintain sterility through their sealed, disposable design. The entire separation process occurs in a closed, sterile environment from sample input to plasma output, eliminating exposure risks associated with traditional open centrifugation methods.
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 method produces highly pure plasma serum with minimal cellular material, reduces the risk of sample contamination, and simplifies the process, allowing for automated and sterile separation of blood components in a fraction of the time required by traditional methods.
Implementation Method 1
holding the whole blood in the microfluidic channel for an amount of time necessary to effectuate substantial sedimentation, resulting in a top layer that comprises plasma serum and a bottom layer that comprises cells and other solid matter
Data Source
AI summary
A microfluidic device and method of using same to separate whole blood into at least a plasma serum fraction and a red blood cell-containing fraction. The microfluidic device uses the principle of sedimentation and the different densities of the cells relative to the plasma serum to separate whole blood into at least the two fractions.