Microfluidic Particle Isolation Using Vortex Trapping and Dielectrophoresis
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Solution Overview
Problem
Current methods fail to rapidly isolate rare cells, such as circulating tumor cells, from large quantities of other particles with high purity, as existing devices often retain non-negligible amounts of erythrocytes and lymphocytes and do not achieve 100% single-cell purity.
Innovation Solution
A microfluidic system with a microfluidic circuit containing channels and chambers that utilize a trapping system with vortex generation and dielectrophoretic or magnetic forces to selectively trap larger particles, allowing smaller particles to pass through, while a control unit manages fluid flow to maintain desired vortex conditions for efficient separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional isolation devices are used, then isolation speed is improved, but purity of isolated cells deteriorates (non-negligible quantities of erythrocytes and lymphocytes remain)
Solution Approach 1:
The microfluidic device segments the isolation process into distinct functional zones: a first microfluidic channel for initial separation, a second microfluidic channel for further purification, and multiple holding pens for staged collection. This segmentation allows sequential filtering that achieves both speed and 100% purity by progressively eliminating different cell types across multiple stages rather than relying on a single isolation step.
2Device complexity
If conventional isolation devices are used, then device complexity is reduced, but isolation purity deteriorates (cannot achieve 100% single-cell purity)
Solution Approach 1:
The microfluidic device integrates multiple functions into a single unified system: it performs magnetic separation, dielectrophoretic separation, and staged collection all within one device architecture. The multiple holding pens serve dual purposes as both separation chambers and collection reservoirs, eliminating the need for multiple separate devices while achieving 100% purity through combined separation mechanisms.
3Productivity
If rapid isolation is implemented, then productivity is improved, but measurement precision deteriorates (difficulty in verifying 100% purity)
Solution Approach 1:
The device incorporates optical detection systems that provide real-time feedback on cell composition in each holding pen. This feedback mechanism allows immediate verification of purity levels during the rapid isolation process, enabling the system to confirm 100% single-cell purity without compromising productivity, as the verification occurs concurrently with the isolation process rather than requiring separate post-processing validation.
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 system achieves high selectivity and purity in isolating target particles, with over 90% of the desired type being moved and separated, enabling efficient isolation of rare cells from mixed samples.
Implementation Method 1
a trapping system, in particular comprising a microfluidic channel (7) provided with at least one segment (16) shaped so as to generate, as a consequence of a flow of fluid flowing through the microfluidic channel (7) itself, a vortex at the segment (16) designed to trap the particle (2)
Implementation Method 2
The particle moving system is chosen in the group consisting of: travelling waves, thermal flow, local fluid movements generated by electro thermal flow, local fluid movements generated by electro-hydrodynamic forces, dielectrophoresis, optical tweezers, opto-electronic tweezers, light-induced dielectrophoresis, magnetophoresis, acoustophoresis
Implementation Method 3
The particle moving system is chosen in the group consisting of: travelling waves, thermal flow, local fluid movements generated by electro thermal flow, local fluid movements generated by electro-hydrodynamic forces, dielectrophoresis, optical tweezers, opto-electronic tweezers, light-induced dielectrophoresis, magnetophoresis, acoustophoresis
Data Source
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AI summary
A microfluidic method and system (1) for the recovery of particles (2); while a sample is fed along a plurality of channels (7), some particles (2) of a given type are trapped at the segments (16) of the channels (7); keeping a fluid flow flowing along the channels (7) further particles (3) of different type are moved away and unloaded through an outlet (6); at this point, a movement device (26), for example provided with a dielectrophoresis system, directly exerts a force on each particle (2) of given type and selectively conveys it to a collection area (25).