Dielectrophoresis Crossover Frequency Determination
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Solution Overview
Problem
Existing dielectrophoresis (DEP) devices face challenges in accurately determining the cross-over frequency of particles, leading to variations in particle separation efficiency, particularly in biological applications where precise separation of target cells from non-target cells is critical for medical assessments and treatments.
Innovation Solution
A method and system that captures image sequences of particles under varying DEP forces, using image analysis to determine the DEP cross-over frequency, allowing for accurate identification and separation of particles by applying an alternating current (AC) electric field at the frequency where the electrical impedance of cells equals that of the fluid medium, enabling efficient separation of target cells from non-target cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional DEP devices are used to determine cross-over frequency, then particle separation can be performed, but measurement precision of cross-over frequency is poor leading to variations in separation efficiency
Solution Approach 1:
The system continuously monitors particle position in real-time during frequency sweeping and uses this feedback to automatically identify the cross-over frequency when particle motion changes direction. This closed-loop feedback mechanism eliminates manual determination errors and achieves precise, repeatable cross-over frequency measurements, directly resolving the contradiction between measurement precision and separation reliability
Solution Approach 2:
The patent replaces manual visual inspection and mechanical frequency adjustment with automated image analysis and electronic frequency control. The computer system automatically captures particle images, analyzes position changes, determines cross-over frequency, and adjusts the AC field frequency accordingly, eliminating human error and achieving consistent high-precision measurements that improve separation reliability
2Measurement precision
If frequency sweeping is performed to identify cross-over frequency, then accurate particle characterization is achieved, but time consumption increases
Solution Approach 1:
The system performs preliminary frequency sweeping to rapidly identify the approximate cross-over frequency range before conducting detailed measurements. By pre-sweeping through a broad frequency range and detecting where particle motion changes direction, the system narrows down the search area, allowing subsequent precise characterization to be completed much faster, thus resolving the time-precision trade-off
Solution Approach 2:
The patent implements continuous real-time monitoring of particle position throughout the frequency sweeping process, rather than taking discrete measurements. The system continuously captures images and tracks particle motion, ensuring that the cross-over event is never missed and allowing immediate identification of the exact cross-over frequency, thereby reducing total measurement time while maintaining high precision
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 allows for high recovery rates of target cells, typically above 60%, by accurately determining the DEP cross-over frequency, ensuring efficient separation and analysis without damaging or losing desired cells, and provides a non-invasive means to assess cell viability and differentiation.
Implementation Method 1
Dielectrophoresis ('DEP') refers to the force experienced by particles suspended in a fluid medium in applied electric field gradients. The dielectrophoretic force is, generally, speaking, the interaction of a non-uniform electric field with the dipole moment it induces in an object.
Implementation Method 2
The system and method also captures image sequences of the particles and, using image analysis, determines the response of each particle to the electrical field it is experiencing.
Data Source
AI summary
The present invention provides a new method for accurately identifying DEP cross-over frequencies of one or more particles in a sample, and quickly and efficiently conveying that information to assist in the separation, e.g., DEP separation, or analysis of the one of more particles under examination or investigation. The present invention also provides an apparatus and method for monitoring the dielectrophoretic response of one or more particles and determining the DEP cross-over frequency of particles of interest.