Magnetic Sorting Microfluidic Chip Submicron Resolution
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Solution Overview
Problem
Current magnetic sorting technologies face limitations in resolving the size difference of submicron biological samples, particularly in negative magnetophoresis sorting, which is restricted to a resolution of ≥3.5 microns due to the distance between permanent magnets and the sorting channel, limiting the sorting of particles smaller than 5 microns.
Innovation Solution
A magnetic sorting microfluidic chip design featuring a substrate with a micro-channel unit and magnetic sorting unit, including permanent magnets, high-permeability alloys, and magnetic pole arrays, which generate high-intensity, high-gradient magnetic fields on both sides of the sorting channel, allowing for precise separation of particles based on size by reducing the distance between the magnets and the sorting channel to 1-25 microns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If permanent magnets are positioned far from the sorting channel (≥500 microns), then the system structure is simple and easy to manufacture, but the magnetic field intensity and gradient are insufficient, limiting sorting resolution to ≥3.5 microns
Solution Approach 1:
The patent transitions from planar magnetic pole arrangements to three-dimensional magnetic pole arrays with multiple layers stacked vertically. This dimensional change allows the magnetic poles to be positioned much closer to the sorting channel (1-25 microns) while maintaining a compact chip footprint, thereby achieving high magnetic field intensity and submicron sorting resolution without excessive structural complexity
Solution Approach 2:
The patent employs nested magnetic pole arrays where smaller magnetic poles are positioned within or between larger poles in multiple stacked layers. This nesting arrangement maximizes the magnetic field gradient in the sorting channel region while maintaining a compact overall structure, enabling close proximity positioning (1-25 microns) without proportionally increasing device complexity
2Measurement precision
If the distance between permanent magnets and sorting channel is reduced to 1-25 microns, then sorting resolution improves to submicron scale (≥0.5 microns), but the manufacturing precision requirements increase significantly
Solution Approach 1:
The patent incorporates magnetic pole positioning structures and alignment features during the chip fabrication process itself, allowing magnetic poles to be pre-positioned with high precision relative to the sorting channel. This preliminary action ensures that when permanent magnets are attached to the magnetic poles, the required 1-25 micron positioning accuracy is achieved without requiring post-fabrication adjustment
Solution Approach 2:
The patent uses magnetic pole arrays as intermediaries between the permanent magnets and the sorting channel. The magnetic poles are integrated into the chip structure with precise positioning features, serving as a mediator that transfers the magnetic field from permanent magnets to the sorting region while maintaining the required 1-25 micron distance control through structural design rather than direct magnet-to-channel positioning
3Measurement precision
If conventional magnetic sorting methods are used, then the system is simple to operate, but the sorting resolution is limited to micron scale and cannot effectively separate submicron particles
Solution Approach 1:
The patent changes the magnetic field parameters by implementing high-gradient magnetic fields through closely spaced magnetic pole arrays (1-25 microns) with opposite polarities. This parameter change enables the system to resolve submicron particle size differences (≥0.5 microns) while maintaining ease of operation, as the improved resolution is achieved through structural design rather than complex operational procedures
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 solution enhances the resolution of negative magnetophoresis sorting from the micron scale to the submicron scale, enabling the separation of particles as small as 0.5 microns, improving the sorting size difference resolution and increasing throughput, allowing for efficient sorting of submicron biological samples.
Implementation Method 1
high-permeability alloys are configured to conduct magnetic fields of the permanent magnets to the magnetic pole arrays
Implementation Method 2
magnetic pole arrays generate two magnetic fields having high intensity, high gradient, and opposite polarities
Implementation Method 3
enhances the resolution of negative magnetophoresis sorting from the micron scale to the submicron scale
Implementation Method 4
magnetic pole arrays generate two magnetic fields having high intensity, high gradient, and opposite polarities on left and right positions of the same side of the sorting channel
Data Source
AI summary
The present invention provides a magnetic sorting microfluidic chip, including a substrate, a chip model material layer, a micro-channel unit and a magnetic sorting unit, where the chip model material layer is disposed on the substrate, and the micro-channel unit and the magnetic sorting unit are both disposed in the chip model material layer; the micro-channel unit includes a sorting channel and magnetic pole channels; the sorting channel is provided with a plurality of sorting channel inlets and a plurality of sorting channel outlets; and the magnetic sorting unit includes permanent magnets, high-permeability alloys, and magnetic pole arrays disposed in the magnetic pole channels, where the high-permeability alloys are configured to conduct magnetic fields of the permanent magnets to the magnetic pole arrays, so that the magnetic pole arrays generate magnetic fields having opposite polarities on left and right positions of the sorting channel.