Microfluidic Cell Sorter Using Deformability-Based Separation
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Solution Overview
Problem
Conventional macroscale methods for cell separation, such as membrane filtration and density gradient centrifugation, are labor-intensive, prone to clogging, and can cause mechanical stress to cells, leading to phenotype changes and cell loss, making them inefficient for processing clinical blood samples effectively.
Innovation Solution
Microfluidic devices with specifically designed linear and spiral channels that utilize aspect ratios to isolate cells based on deformability and size, allowing for continuous high-flow rate processing without chemical modification, enabling the detection and isolation of diseased cells, including circulating tumor cells and synchronized cells, with high efficiency and viability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional macroscale methods (membrane filtration, density gradient centrifugation) are used for cell separation, then cell separation can be achieved, but the process becomes labor-intensive, prone to clogging, and causes mechanical stress leading to phenotype changes and cell loss
Solution Approach 1:
The patent replaces conventional macroscale mechanical separation methods (membrane filtration, density gradient centrifugation) with microfluidic devices that utilize controlled fluid dynamics at the microscale. The microfluidic channels create specific flow patterns and shear stress distributions that enable cell separation based on deformability differences without requiring complex multi-step mechanical operations, thereby reducing labor intensity and device complexity while maintaining separation effectiveness
Solution Approach 2:
The patent changes the scale parameter from macroscale to microscale, which fundamentally alters the fluid dynamics and cell behavior. At the microscale, cells experience different shear stress conditions and flow regimes that enable separation based on intrinsic properties like deformability. This parameter change eliminates the need for complex sample preparation steps and reduces mechanical stress on cells while achieving reliable separation
2Reliability
If membrane filtration is used for cell separation, then target cells can be filtered out, but the method is easily susceptible to clogging and requires frequent cleaning
Solution Approach 1:
The patent replaces membrane filtration with microfluidic channel-based separation that does not rely on physical membranes. The microfluidic devices use controlled flow through open channels with specific aspect ratios, creating shear-dependent separation without clogging risks. This substitution maintains filtration efficiency while eliminating the need for frequent cleaning and enabling continuous processing
Solution Approach 2:
The patent avoids using porous membrane materials that are prone to clogging. Instead, it employs non-porous microfluidic channels with controlled geometry that allow cells to be separated based on their deformability in response to shear stress. This eliminates the clogging issue inherent in membrane-based filtration while maintaining separation efficiency
3Reliability
If conventional filtration and centrifugation techniques are used, then cell separation can be achieved, but mechanical stress induces changes in the original phenotype of target cells
Solution Approach 1:
The patent changes the stress regime from high mechanical stress (centrifugation, forceful filtration) to controlled low shear stress microfluidic flow. The microfluidic devices operate at flow rates and channel dimensions that generate gentle shear forces sufficient to separate cells based on deformability differences but low enough to prevent mechanical damage and phenotype changes. This parameter optimization maintains both separation capability and cell integrity
Solution Approach 2:
The patent replaces high-stress mechanical separation methods with microfluidic shear-based separation. The microfluidic channels create controlled shear stress fields that exploit differences in cell deformability without the extreme mechanical forces of centrifugation or forceful filtration. This substitution achieves reliable separation while preserving cell phenotype integrity
4Reliability
If microfluidics systems are used for blood analysis, then better control of cellular microenvironment can be achieved, but processing throughput is low due to sample dilution or slow flow rates
Solution Approach 1:
The patent optimizes the aspect ratio parameter of microfluidic channels (width-to-height ratio) to enhance shear stress distribution and cell separation efficiency. By carefully selecting aspect ratios, the devices achieve effective cell separation at higher flow rates without requiring sample dilution. This parameter optimization simultaneously maintains microenvironment control and increases processing throughput to handle clinical blood sample volumes
Solution Approach 2:
The patent employs dynamic flow control in the microfluidic devices, allowing adjustment of flow rates to optimize both separation quality and processing speed. The devices are designed to operate effectively across a range of flow rates, enabling high-throughput processing of clinical samples while maintaining the controlled microenvironment necessary for reliable cell separation based on deformability
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 microfluidic devices achieve efficient separation and isolation of target cells with high throughput, maintaining cell viability and reducing processing time and cost, making them suitable for clinical samples, including those with high hematocrit levels.
Implementation Method 1
The separation relies on the interplay between the inertial lift forces, due to the large cell size, and the Dean drag force
Implementation Method 2
The separation relies on the interplay between the inertial lift forces, due to the large cell size, and the Dean drag force
Data Source
AI summary
A method of detecting one or more diseased blood cells in a blood sample includes introducing a blood sample into at least one inlet of a microfluidic device comprising one or more linear channels wherein each channel has a length and a cross-section of a height and a width defining an aspect ratio adapted to isolate diseased blood cells along at least one portion of the cross-section of the channel based on reduced deformability of diseased blood cells as compared to non-diseased blood cells, wherein diseased blood cells flow along a first portion of the channel to a first outlet and non-diseased blood cells flow along a second portion of the channel to a second outlet. The one or more channels can be adapted to isolate cells along portions of the cross-section of the channel based on cell size. In some embodiments, the one or more channels can be spiral channels.