Microfluidic Device Magnetic Cell Separation
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Solution Overview
Problem
Conventional methods for isolating and immobilizing cells in microfluidic devices are limited in their ability to efficiently separate and analyze cells based on their physical and magnetic properties, particularly in heterogeneous cell populations like blood samples, without the need for exogenous labeling techniques.
Innovation Solution
A microfluidic device with a sample inlet, optional cell selective filter, and cell retention body that uses a combination of cell size and magnetic properties to separate and immobilize cells within defined microchannels, featuring metallic films and magnets to concentrate magnetic fields and facilitate precise analysis of physical and biochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cell separation methods are used, then cell separation efficiency is improved, but the device complexity and inability to immobilize cells for analysis worsens
Solution Approach 1:
The device is divided into distinct functional modules: a separation chamber with ferromagnetic elements for cell separation, and an analysis chamber with sample wells for cell immobilization and measurement. This segmentation allows each module to perform its specific function efficiently while maintaining overall system manageability.
Solution Approach 2:
The invention transitions from simple flow-based separation to a multi-dimensional approach by incorporating vertical magnetic field gradients through ferromagnetic elements positioned at specific heights above the channel. This enables simultaneous separation and immobilization in different spatial zones within the same device.
2Measurement precision
If exogenous labeling techniques are used, then cell identification accuracy is improved, but the ease of operation and sample preparation complexity worsens
Solution Approach 1:
The device exploits the inherent magnetic properties of hemoglobin in red blood cells to achieve separation and identification without requiring external labels or markers. The ferromagnetic elements interact directly with the paramagnetic RBCs, enabling label-free detection and analysis.
Solution Approach 2:
The invention changes the magnetic field parameters (strength, gradient, orientation) to selectively interact with cells based on their inherent magnetic properties. By adjusting these parameters, the system can differentiate between cell types without exogenous labeling while maintaining operational simplicity.
3Speed
If cells are not immobilized, then the speed of processing is improved, but the measurement precision and analysis capability worsens
Solution Approach 1:
Cells are pre-separated and immobilized in specific sample wells before measurement begins. This preliminary immobilization step ensures that cells are properly positioned and held stable during subsequent analysis, enabling precise measurements without compromising overall processing speed.
Solution Approach 2:
The device operates in periodic cycles: first separating cells through the magnetic field, then immobilizing them in analysis wells, and finally performing measurements. This periodic operation allows high-speed processing while ensuring precise measurements during the analysis phase.
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
Enables efficient separation and immobilization of target cells, allowing for detailed analysis of their physical and biochemical properties using advanced measurement systems, improving the precision and efficiency of cell isolation and analysis in microfluidic devices.
Implementation Method 1
The high gradient magnetic field is generated when an external magnetic field is applied normal to the axis of a microfluidic channel having a small ferromagnetic wire disposed along its length
Implementation Method 2
RBCs are magnetic due to their high content of hemoglobin. Hemoglobin is a protein comprising of four polypeptide chains, each of which contains a central iron atom capable of reversibly binding oxygen. In its deoxygenated form, each of hemoglobin's iron atoms contains four unpaired electrons, giving the protein a paramagnetic moment
Implementation Method 3
Blood cells flowing parallel to the ferromagnetic wire experience a magnetic force, whereby RBCs are forced away from the magnetic wire and into an outlet channel
Implementation Method 4
a metallic film positioned on or below the sample well base... the metallic film concentrating the applied magnetic field within the one or more than one sample well
Data Source
AI summary
A microfluidic device for the separation and immobilization of one or more cells into sample wells based on one or more physical properties of the one or more cells is provided. Metallic film or magnets are positioned on or below the wells. Openings in the device above the sample wells accommodate a measurement system to determine one or more physical characteristics or properties of the one or more cells immobilized within the microfluidic device. A method for determining a property or one or more physical characteristics of the immobilized one or more cells is also provided.