Liquid-Liquid Interface Microfluidic Circulation
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Solution Overview
Problem
Current microfluidic technologies face challenges such as the need for large electromagnets, limited lifetime of paramagnetic liquid tubes due to ion diffusion, toxicity of paramagnetic ions, and limited stable geometries, which hinder their adoption in microfluidics, especially for life science applications and sub-millimeter scale operations.
Innovation Solution
A device and method utilizing a magnetic field to create a liquid-liquid interface where a less-paramagnetic liquid circulates within a more-paramagnetic liquid without contact with a solid wall, using a configuration of magnetic field elements like permanent or electropermanent magnets to stabilize the liquid tube and antitube, allowing for improved stability, longer lifetime, and compact magnetic field generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large electromagnets are used to generate magnetic fields for liquid tube stabilization, then magnetic field strength is sufficient, but device size and complexity increase significantly
Solution Approach 1:
The patent replaces electromagnets (electrical-mechanical system) with permanent magnets (static magnetic field system) to generate the magnetic fields needed for liquid tube stabilization. This substitution eliminates the need for power supplies, control circuits, and moving parts associated with electromagnets, significantly reducing device complexity and size while maintaining sufficient magnetic field strength for confining paramagnetic liquid tubes in microfluidic channels.
2Ease of operation
If paramagnetic liquid tubes are used for fluid transport, then magnetic control is achieved, but lifetime is limited due to ion diffusion
Solution Approach 1:
The patent changes the chemical composition parameters of the liquid tubes by using non-aqueous paramagnetic liquids (such as organic solvents with dissolved paramagnetic salts) instead of traditional aqueous paramagnetic solutions. This parameter change reduces ion diffusion across the liquid-liquid interface, thereby extending the lifetime of paramagnetic liquid tubes while maintaining their magnetic controllability for fluid transport and manipulation.
3Quantity of substance
If paramagnetic ions are used to create magnetic susceptibility difference, then magnetic field control is enabled, but toxicity increases
Solution Approach 1:
The patent changes the chemical nature of paramagnetic liquids by replacing aqueous solutions containing toxic paramagnetic ions (such as holmium, gadolinium, or cobalt salts) with non-aqueous paramagnetic liquids or paramagnetic liquids containing biocompatible paramagnetic materials. This parameter change maintains the necessary magnetic susceptibility difference for magnetic field control while significantly reducing or eliminating toxicity, making the system suitable for life science applications.
4Shape
If solid walls are used to confine liquids in microfluidic channels, then geometric stability is achieved, but surface-to-volume ratio increases causing fouling and adsorption
Solution Approach 1:
The patent uses a liquid-liquid interface (another liquid) instead of solid walls to confine and guide the paramagnetic liquid tube in microfluidic channels. This hydraulic approach creates a liquid channel within a liquid medium, stabilized by magnetic fields. The liquid-liquid interface eliminates solid surface contact, thereby preventing fouling and adsorption while maintaining geometric stability through magnetic confinement and interfacial tension.
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
This approach enables stable and long-lasting liquid tubes without solid wall contact, facilitating efficient fluid mixing and circulation on a sub-millimeter scale, suitable for life science applications, with reduced toxicity and cost-effective industrialization, and improved mixing efficiency compared to traditional microfluidic devices.
Implementation Method 1
These separation methods make use of the magnetic field gradient force and the difference in susceptibility of material that is attracted to the magnet and its surrounding medium
Implementation Method 2
circulating a less-paramagnetic liquid into an enclosing more paramagnetic liquid or for circulating a more-paramagnetic liquid into an enclosing less paramagnetic liquid
Data Source
AI summary
Disclosed is a device including at least one circulating zone and at least one fluid including at least one more-paramagnetic liquid and at least one less-paramagnetic liquid forming a liquid-liquid interphase, the device including at least one element generating, in the circulating zone, a magnetic field, wherein the less-paramagnetic liquid is surrounded by the more-paramagnetic liquid in the circulating zone or wherein the more-paramagnetic liquid is surrounded by the less-paramagnetic liquid in the circulating zone. Also disclosed is a method including circulating at least one less-paramagnetic liquid inside one or more circulating zones of a device including at least one circulating zone and at least one more-paramagnetic liquid in the circulating zone.