Microchannel Cartridge Flow Control for Low-Volume B Cell Separation
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Solution Overview
Problem
Existing microchannel systems face challenges in maintaining fine control of flow rates and efficiently separating cells, particularly those with low abundance, such as B cells, due to their scarcity in blood samples, requiring large sample volumes and additional enrichment protocols.
Innovation Solution
A microchannel cartridge utilizing gravity-assisted flow control and magnetic separation, combined with a serpentine channel design and antibody coatings, allows for efficient capture and separation of target cells or cell fragments using a small sample volume without external pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical pumps are used to control flow rate in microchannels, then flow rate control is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical pumps with passive flow control mechanisms including surface tension forces, gravity, and pressure differentials. The microchannel system uses hydrophobic/hydrophilic surface properties and capillary action to control fluid flow without mechanical components, thereby reducing device complexity while maintaining flow rate control capability
Solution Approach 2:
The microchannel system utilizes inherent physical properties of the channel structure (surface tension, gravity, pressure gradients) to automatically control flow rates without external mechanical intervention. The system self-regulates fluid dynamics through its geometric design and surface properties, eliminating the need for complex pumping mechanisms
2Productivity
If conventional cell separation methods are used, then cell separation is achieved, but sample volume and processing time increase
Solution Approach 1:
The patent divides the cell separation process into distinct functional zones within the microchannel system, including sampling chambers, separation channels with different hydrophobicity levels, and collection chambers. This segmentation enables efficient separation of target cells from background cells using minimal sample volumes through staged processing
Solution Approach 2:
The system changes physical parameters such as hydrophobicity/hydrophilicity of channel surfaces and gravitational orientation to optimize cell separation. By adjusting these parameters, the system achieves high enrichment factors (up to 97-fold for B cells) from small sample volumes of 10 μL or less
3Reliability
If larger sample volumes are used for cell separation, then separation quality improves, but portability and applicability to POC diagnostics decrease
Solution Approach 1:
The patent transitions from bulk fluid processing to confined micro-scale processing by utilizing three-dimensional microchannel structures with controlled surface properties. This dimensional change enables effective cell separation at micro-volumes (10 μL or less) while maintaining separation quality, thereby enabling POC diagnostic applications
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 up to 97 times more B cell enrichment in 10 μL of whole blood compared to traditional pump-based methods, enabling effective cell separation and detection in a portable, all-in-one system.
Implementation Method 1
Flow rate is also controlled by the surface properties of materials used to fabricate microchannels and the dimensions and structures of the microchannel. More hydrophobic materials decrease flow rate as cohesion between fluid molecules is stronger than the adhesion of the fluid to the surface of the microchannel. Smaller channels increase flow rate due to stronger capillary action.
Implementation Method 2
the microchannel cartridge is adapted to allow a gravity-assisted loading of the fluid sample into the inlet by retarding passage of the fluid sample into the second flow channel when the inlet is positioned below the outlet and a gravity-assisted separation of the cells or cell fragments in the fluid sample by facilitating passage of unwanted cells or cell fragments into the second flow channel when the inlet is elevated above the outlet
Data Source
AI summary
The present disclosure provides novel devices and methods for separating cells or cell fragments through fine control of a flow rate in the microchannel using a combined force of capillary and gravity without any external pumps. The disclosed devices and methods are unexpectedly effective in capturing various target cells, including rare bioparticles such as B cells, using only a small amount of blood sample.