Microfluidic Impedance Sensor for Label-Free Cell Sorting
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Solution Overview
Problem
Current microfluidic systems for cell sorting and diagnostics require complex and costly fluorescence-activated cell sorting operations, which are not efficient for determining and moving cells without tagging them with fluorescent labels, and often require multiflow control systems.
Innovation Solution
A microfluidic apparatus with a channel and foyer system that uses an impedance sensor to detect and identify cells based on their electrical signature, allowing for controlled movement of cells without fluorescent labels, using a controller to direct cells to different areas for further analysis or dispensing, and an actuator to manage fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorescence-activated cell sorting operations are used, then cell sorting and diagnostics can be performed, but the system becomes complex and costly
Solution Approach 1:
The patent extracts the fluorescent labeling step from the cell sorting process entirely. Instead of requiring fluorescent tags and complex optical detection systems, the invention uses label-free impedance sensing to detect and sort cells based on their intrinsic electrical properties, thereby simplifying the system while maintaining sorting accuracy
Solution Approach 2:
The patent replaces the optical detection and sorting mechanism (fluorescence-activated cell sorting) with an electrical impedance-based detection and dielectrophoretic sorting mechanism. This substitution eliminates the need for complex optical systems, lasers, and fluorescent reagents, significantly reducing system complexity and cost
2Reliability
If fluorescence-activated cell sorting operations are used, then cell sorting can be performed, but the operation becomes costly
Solution Approach 1:
The patent employs inexpensive microfabricated impedance sensors and dielectrophoretic actuators that can be mass-produced using standard semiconductor fabrication techniques. These replace expensive fluorescent reagents, optical components, and specialized equipment, dramatically reducing operational costs while maintaining cell sorting accuracy
Solution Approach 2:
The substitution of optical detection with electrical impedance detection eliminates costly fluorescent reagents, lasers, and optical detectors. The dielectrophoretic sorting mechanism uses affordable electrical fields instead of expensive optical sorting systems, reducing both capital equipment costs and per-operation costs
3Ease of operation
If multiflow control systems are used, then fluid flow can be controlled, but the device complexity increases
Solution Approach 1:
The patent merges multiple fluid control functions into a single integrated microfluidic channel design. The microfabricated impedance sensor and dielectrophoretic actuator are combined in one device, allowing fluid flow control and cell sorting to be achieved through a unified system rather than separate multiflow control components
Solution Approach 2:
The microfabricated device performs multiple functions (fluid flow control, cell detection, cell sorting) within a single integrated platform. The impedance sensor simultaneously detects cell presence and characteristics, while the dielectrophoretic field provides sorting capability, eliminating the need for separate specialized control systems
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 determination and movement of cells within microliter to picoliter volumes without multiflow control systems, allowing for cost-effective and simpler cell sorting and diagnostics, including health diagnostics for diseases like HIV, Malaria, Tuberculosis, cancer, and cardiac diseases.
Implementation Method 1
A sensor is positioned to detect the passage of a particle of interest, e.g., a cell, through the channel
Implementation Method 2
microfluidic systems and devices such as microfluidic devices or chips
Data Source
Figure 1A~1B
Figure 1C~2
Figure 3~4
AI summary
According to an example, a microfluidic apparatus may include a fluid slot and a foyer that is in fluid communication with the fluid slot via a channel having a relatively smaller width than the foyer. The microfluidic apparatus may also include an electrical sensor to measure a change in an electrical field caused by a particle of interest in a fluid passing through the channel from the fluid slot to the foyer, an actuator to apply pressure onto fluid contained in the foyer, and a controller to receive the measured change in the electrical field from the electrical sensor, determine, from the received change in the electrical field, an electrical signature of the particle of interest, and control the actuator to control movement of the particle of interest based upon the determined electrical signature of the particle of interest.