Microchip Dielectrophoresis Separation Lysis PCR
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Solution Overview
Problem
Current methods for treating biological samples using dielectrophoresis face challenges in efficiently manipulating particles, particularly in reducing diagnostic time and minimizing contamination risks, while also dealing with heating issues due to applied electric fields.
Innovation Solution
A device and method utilizing planar electrodes in a microchannel for particle separation, lysis, and amplification, employing dielectrophoresis to trap and lyse target cells using RF and DC fields, and subsequent PCR for amplification, all within a single chip to reduce costs and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If RF electric fields are applied via microelectrodes for dielectrophoresis, then particle manipulation and separation is achieved, but heating issues occur due to applied electric fields
Solution Approach 1:
The patent applies periodic RF electric fields at specific frequencies (e.g., 1-100 MHz) to generate dielectrophoretic forces for particle manipulation. By using alternating fields rather than continuous DC fields, the system achieves particle separation while allowing thermal dissipation between cycles, reducing cumulative heating effects in the sample
Solution Approach 2:
The patent optimizes multiple parameters including RF frequency, field amplitude, and pulse duration to maximize dielectrophoretic force while minimizing heating. By adjusting the frequency spectrum and field strength dynamically, the system achieves effective particle manipulation at lower temperatures
2Reliability
If multiple separate devices are used for separation, lysis, and amplification, then each function can be optimized, but diagnostic time increases and contamination risks increase
Solution Approach 1:
The patent integrates three separate functions (dielectrophoretic separation, electrical lysis, and PCR amplification) into a single microfluidic chip device. Sample particles are separated by DEP forces, then lysed by applied electric fields, and finally amplified by PCR all within the same closed system, eliminating transfer steps that cause contamination and reducing total diagnostic time
Solution Approach 2:
The microchip device performs multiple functions sequentially: it acts as a separator for particle classification, a lysis chamber for cell disruption, and a PCR reactor for DNA amplification. This multi-functional integration allows one device to replace multiple separate instruments, streamlining the diagnostic workflow
3Reliability
If high amplitude DC voltage pulses are applied for cell lysis, then membrane integrity is destroyed for PCR, but device complexity increases
Solution Approach 1:
The patent replaces mechanical or chemical lysis methods with electrical field-induced lysis. High amplitude DC voltage pulses (e.g., 100-1000 V) are applied directly through the microelectrodes to create electroporation effects that destroy cell membranes, enabling DNA release for PCR without requiring complex mechanical disruption devices or chemical reagent 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
This approach enables efficient separation, lysis, and amplification of biological particles, reducing overall diagnostic time and contamination risks, while allowing for smaller sample volumes and minimizing heating-related issues.
Implementation Method 1
DEP exploits frequency dependent differences in polarizability between the particles to be treated and the surrounding liquid that occur when RF (Radio Frequency) electric fields are applied thereto via microelectrodes
Implementation Method 2
the microelectrodes can additionally be used to apply DC (Direct Current) voltage pulses of high amplitude (of the order of 100 V) for short times (of the order of microseconds) to destroy membrane integrity of dielectrophoretically captured cells
Implementation Method 3
Application of electric fields to conductive solutions is accompanied by heating
Data Source
AI summary
A plurality of planar electrodes (5) in a microchannel (4) is used for separation, lysis and PCR in a chip (10). Cells from a sample are brought to the electrodes (5). Depending on sample properties, phase pattern, frequency and voltage of the electrodes and flow velocity are chosen to trap target cells (16) using DEP, whereas the majority of unwanted cells (17) flushes through. After separation the target cell (16) are lysed while still trapped. Lysis is carried out by applying RF pulses and/or thermally so as to change the dielectric properties of the trapped cells. After lysis, the target cells (16) are amplified within the microchannel (4), so as to obtain separation, lysis and PCR on same chip (1).