Particle Separation Using Time-Variable Force Fields
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Solution Overview
Problem
Existing methods for separating particles based on dielectrophoresis face limitations, including inability to discriminate particles subject to the same force, requirement of liquid flows, and lack of precise control over particle position post-separation, which are undesirable in many applications, especially in biological sample analysis.
Innovation Solution
A method and apparatus utilizing time-variable, non-uniform force fields with stable-equilibrium points that are translated at controlled speeds to separate particles based on their response to the force field, allowing for precise control over particle movement and separation without the need for liquid flows, enabling the isolation and quantification of particles based on their physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dielectrophoresis is used to separate particles, then particles can be separated based on their physical properties, but particles subject to the same force (both NDEP or both PDEP) cannot be discriminated
Solution Approach 1:
The patent applies dynamic modulation of the electric field by alternating between two frequencies (f1 and f2), creating time-varying force fields that translate stable-equilibrium points. This dynamic approach allows particles subject to the same initial force to be separated based on their differential response speeds to the frequency-modulated field, enabling discrimination of particles that static fields cannot distinguish.
Solution Approach 2:
The patent changes the frequency parameter of the applied electric field, switching between f1 and f2 at different time intervals. This parameter modulation creates distinct stable-equilibrium point translations that exploit differences in particle response characteristics, allowing separation of particles that would otherwise be indistinguishable under constant frequency conditions.
2Manufacturing precision
If liquid flows are used in separation methods, then particle separation can be achieved, but precise control over particle position after separation cannot be maintained
Solution Approach 1:
The patent replaces mechanical liquid flow systems with an electric field-based manipulation system. By using time-variable electric fields to create and translate stable-equilibrium points, the system achieves particle separation and positioning without relying on fluid dynamics, thereby maintaining precise control over particle positions throughout the separation and measurement processes.
3Device complexity
If Travelling waves are used for particle separation, then liquid flow requirements are eliminated, but accurate control on particle position cannot be maintained
Solution Approach 1:
The patent employs periodic switching between two frequencies (f1 and f2) to modulate the electric field. This periodic action creates controlled translations of stable-equilibrium points that can be precisely timed and positioned, allowing accurate particle position control without requiring liquid flows or Travelling wave mechanisms.
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 effectively separates particles by exploiting differences in their response to the force field, allowing for accurate control over particle position and quantity determination, even when particles are subject to the same force, and does not require liquid flows, addressing the limitations of existing methods.
Implementation Method 1
The force fields can be for dielectrophoresis (positive or negative), electrophoresis or electrohydrodynamic motion
Implementation Method 2
The force fields can be for dielectrophoresis (positive or negative), electrophoresis or electrohydrodynamic motion
Implementation Method 3
The stable-equilibrium points of the field are translated in space at a speed substantially comparable to the speed of translation of the fastest particles in the sample so that only these follow by changing position
Data Source
AI summary
The invention pertains to a method and apparatus to separate and quantify particles using time-variable force fields. The force fields can be for dielectrophoresis (positive or negative), electrophoresis, or electrohydrodynamic. In one aspect, the fields are translated and/or modified in space at a speed substantially comparable to the speed of translation of the fastest particles in the sample. The translation and/or modification of the force fields can also occur with varying speed. In another aspect, the field is translated and/or modified in a first direction at high speed. In another aspect, the quantity or size of the particles is determined by an indirect measurement of the speed of movement after varying the force field by means of a relationship between the speed of movement and the volume of the particles. This invention also pertains to an apparatus to produce appropriate field configurations necessary for the selective movement of particles.