Microfluidic Chip for Magnetic Susceptibility Measurement
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Solution Overview
Problem
Conventional methods for measuring the magnetic susceptibility of superparamagnetic nanoparticle beads are not suitable for point-of-care testing due to high costs, power consumption, and limitations in quantitative or high-sensitivity measurements, especially when dealing with small volumes of magnetic fluids.
Innovation Solution
A microfluidic chip equipped with a planar Hall resistive sensor that includes a microfluidic channel system allowing for the continuous measurement of magnetic susceptibility of superparamagnetic nanoparticle beads and droplets in a flowing magnetic fluid, enabling accurate measurement with a small amount of fluid (on the order of picoliters).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (SQUID, VSM) are used to measure magnetic susceptibility, then measurement capability is achieved, but cost and device complexity increase significantly
Solution Approach 1:
The patent replaces complex mechanical measurement systems (SQUID, VSM) with a microfluidic chip-based measurement system that uses fluid flow and magnetic field interaction to measure magnetic susceptibility. The microfluidic chip integrates magnetic electrodes, non-magnetic electrodes, and fluid channels into a compact structure that eliminates the need for large, expensive equipment while maintaining measurement capability.
Solution Approach 2:
The patent changes the measurement approach by using magnetic susceptibility to control fluid flow characteristics in the microfluidic channel. Instead of directly measuring magnetic properties with complex instruments, the system measures how magnetic susceptibility affects fluid behavior (flow rate, droplet formation) under applied magnetic fields, providing indirect but accurate measurement with simpler equipment.
2Measurement precision
If conventional methods are used, then magnetic susceptibility can be measured, but power consumption increases
Solution Approach 1:
The patent replaces power-intensive mechanical measurement systems with a low-power microfluidic system that uses controlled fluid flow and weak magnetic fields. The measurement is performed by observing fluid behavior rather than using high-power sensors, dramatically reducing power consumption while maintaining measurement accuracy.
Solution Approach 2:
The system uses the magnetic properties of the sample itself to drive the measurement process. The magnetic susceptibility of the sample naturally influences fluid flow and droplet formation in the microfluidic channel under applied magnetic fields, eliminating the need for external power-intensive measurement mechanisms.
3Measurement precision
If nanoparticle bead clusters are used for measurement, then measurement is feasible, but quantitative measurement of individual nanoparticles is limited
Solution Approach 1:
The patent segments the measurement process to handle individual nanoparticles or small groups rather than requiring large clusters. The microfluidic system can isolate and measure magnetic susceptibility of discrete samples by controlling fluid flow and droplet formation, enabling quantitative measurement of individual nanoparticles while maintaining statistical significance through repeated measurements.
Solution Approach 2:
The patent changes the sample configuration from large clusters to controlled droplets or individual particles in fluid flow. By adjusting fluid flow rates, magnetic field strengths, and droplet formation parameters, the system optimizes measurement conditions for small sample sizes, enabling accurate quantitative measurement without requiring large nanoparticle clusters.
4Measurement precision
If large volumes of magnetic fluid are used, then measurement signal strength is sufficient, but fluid consumption increases
Solution Approach 1:
The patent segments the magnetic fluid into small droplets or controlled flow streams within the microfluidic channel. This segmentation allows the system to use minimal fluid volumes while maintaining sufficient measurement signals by concentrating the magnetic material in discrete, measurable units that pass through the sensing region sequentially.
Solution Approach 2:
The patent changes the measurement approach to work with small fluid volumes by optimizing magnetic field strength, fluid flow rate, and droplet size parameters. The system compensates for reduced fluid volume by adjusting measurement conditions to enhance signal detection efficiency, enabling accurate measurements with picoliter-scale fluid quantities.
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 microfluidic chip allows for high-accuracy, continuous measurement of magnetic susceptibility of superparamagnetic nanoparticle beads in a flowing fluid, overcoming the limitations of existing methods by minimizing the influence of stray magnetic fields and achieving precise measurements with minimal fluid usage.
Implementation Method 1
a planar Hall resistive sensor comprising an active junction area for sensing the superparamagnetic nanoparticle bead and droplet
Implementation Method 2
Superparamagnetic nanoparticle beads have been used in magnetic biosensors to detect the biomaterials to be analyzed. The superparamagnetic nanoparticle beads are materials which show magnetic properties upon the application of an external magnetic field, but lose the magnetic properties when the magnetic field is removed.
Implementation Method 3
the superparamagnetic nanoparticle beads are magnetized by an externally applied magnetic field to produce a stray magnetic field (Hstray)
Data Source
AI summary
The present invention relates to a microfluidic chip for measuring the magnetic susceptibility of a superparamagnetic nanoparticle droplet and a method for measuring magnetic susceptibility using the same. According to the invention, the magnetic susceptibility of a superparamagnetic nanoparticle can be continuously and accurately measured in a flowing fluid using a microfluidic chip including microfluidic channels.