Microfluidic Cell Sorting Chip With Extended Gas-Deflection Region
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Solution Overview
Problem
The existing microfluidic chips for cell sorting have a small sorting region, leading to short residence time of target cells, which results in low accuracy due to difficulty in accurately blowing target cells into the sorting flow channel with high flow velocity.
Innovation Solution
The microfluidic chip design includes an expanded sorting region with specific angles and distances between flow channels, allowing for extended cell residence time and accurate deflection of target cells into target flow channels using a lower gas pressure, minimizing channel intersections with arc chamfers to guide cells without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the sorting region area is increased, then the residence time of target cells is extended, but the device complexity increases due to additional flow channels and geometric constraints
Solution Approach 1:
The patent extends the sorting region along the flow direction (length dimension) rather than increasing cross-sectional area, achieving longer residence time without proportionally increasing overall device area. The sorting region length L is specifically designed to be 5-15 times the channel width W, creating an elongated geometry that maximizes residence time while minimizing area increase.
Solution Approach 2:
The microfluidic chip is divided into distinct functional regions (sample injection region, sorting region, collection region) with dedicated flow channels for each function. This segmentation allows the sorting region to be optimized independently for extended residence time while other regions handle sample introduction and collection, distributing complexity across modular sections.
2Object-affected harmful factors
If gas pressure is reduced to minimize cell damage, then cell damage decreases, but sorting accuracy may be compromised due to insufficient deflection force
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: gas pressure (0.5-2 psi), channel dimensions (width W, length L), and geometric angles (α=30-60°, β=120-150°). These parameter changes create a balanced system where sufficient deflection force is achieved through optimized channel geometry rather than high gas pressure, minimizing cell damage while maintaining sorting accuracy.
Solution Approach 2:
The patent employs arc chamfers at channel intersections and curved channel designs to guide cell flow smoothly. The arc chamfer radius R is specifically designed as 0.3-1.0 times the channel width W, creating gentle transitions that reduce turbulent flow and cell damage while maintaining effective gas deflection for accurate sorting.
3Productivity
If the flow velocity of cell suspension is increased to improve productivity, then sorting speed increases, but residence time decreases leading to lower sorting accuracy
Solution Approach 1:
The patent compensates for high flow velocity by extending the sorting region length L along the flow direction. The length L is designed to be 5-15 times the channel width W, ensuring that even at high flow velocities, cells have sufficient residence time (L/velocity) for accurate sorting while maintaining high productivity.
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 design enhances cell sorting accuracy by increasing residence time and reducing cell damage, enabling precise sorting with lower gas pressure and minimizing backflow impacts.
Implementation Method 1
the gas inlet flow channel communicates with the sorting flow channel... A distance d between an intersection of the axis of the gas inlet flow channel and the axis of the sorting flow channel and an intersection of the sorting flow channel, the target flow channel and the non-target flow channel is from 0.02 mm to 0.05 mm
Implementation Method 2
The intersections on the side walls where the second flow channel, the gas inlet flow channel, the non-target flow channel and the target flow channel intersect are provided with the arc chamfers
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to a microfluidic chip for sorting living cells. A sample flow channel communicates with a liquid inlet end of a sorting flow channel. A gas inlet flow channel, a target flow channel and a non-target flow channel communicate with a liquid outlet end of the sorting flow channel. An included angle between the target flow channel and the sorting flow channel is from 100° to 130°, and an included angle between the non-target flow channel and the sorting flow channel is from 100° to 140°. A distance between an intersection of an axis of the gas inlet flow channel and an axis of the sorting flow channel and an intersection of the sorting flow channel, the target flow channel and the non-target flow channel is from 0.02 mm to 0.05 mm. In the microfluidic chip of this solution, a sorting region can be expanded so as to extend a residence time of cells in the sorting region, so that target cells can be accurately blown into the target flow channel by a gas flow, thereby increasing an accuracy of cell sorting.