EWOD Magnetic Particle Extraction With Minimal Liquid Carryover
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Solution Overview
Problem
Conventional methods for separating magnetically responsive particles from droplets in EWOD devices result in significant volumes of liquid accompanying the particles, inefficient use of device space, and a risk of particles becoming embedded in the device surfaces.
Innovation Solution
The method involves using a magnetic field to aggregate and separate magnetically responsive particles from a droplet by applying a force, rather than relying on electrowetting to split the droplet, allowing for high capture efficiency with minimal liquid volume and reduced surface area occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrowetting is used to split the droplet for particle separation, then particles can be separated from the droplet, but significant volumes of liquid accompany the particles
Solution Approach 1:
The patent extracts only the magnetically responsive particles from the droplet by applying a magnetic field that pulls particles to the droplet interface, allowing selective removal of particles with minimal liquid attachment. This extraction approach separates particles without splitting the droplet, thus avoiding the problem of significant liquid volume accompanying the particles.
2Productivity
If conventional separation methods are used, then particles can be removed from droplets, but device space is inefficiently utilized
Solution Approach 1:
The magnetic field application enables the same droplet manipulation platform to perform both droplet transport (via electrowetting) and particle separation (via magnetic field), eliminating the need for separate physical separation chambers or additional device components. This multi-functionality optimizes device space utilization while maintaining high separation efficiency.
3Manufacturing precision
If particles are separated by conventional methods, then separation can be achieved, but particles risk becoming embedded in device surfaces
Solution Approach 1:
The magnetic field acts as an intermediary force that pulls particles to the droplet interface without direct contact between particles and device surfaces. The magnetic force mediates the separation process, allowing particles to be extracted from the droplet while minimizing contact with potentially embedding surfaces, thus improving reliability.
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
Achieves selective separation of magnetically responsive particles with minimal liquid volume, enhancing efficiency and reducing the risk of particle embedding, while optimizing device space utilization.
Implementation Method 1
operating the magnet element to apply a magnetic field to the liquid droplet, wherein at least a portion of the magnetically responsive particles aggregate within the liquid droplet in response to the magnetic field; and separating the aggregated magnetically responsive particles from the liquid droplet with the magnetic field, wherein the aggregated magnetically responsive particles move in response to the magnetic field
Implementation Method 2
performing an electrowetting operation to move the liquid droplet along the element array to a location relative to a magnet element
Data Source
AI summary
A method of operating an EWOD device to employs a magnetic field to separate magnetically responsive particles from a polar liquid droplet. The method includes the steps of dispensing a liquid droplet onto an element array of the EWOD device, wherein the liquid droplet includes magnetically responsive particles; performing an electrowetting operation to move the liquid droplet along the element array to a location relative to a magnet element in proximity to that location of the EWOD device; operating the magnet element to apply a magnetic field to the liquid droplet, wherein at least a portion of the magnetically responsive particles aggregate within the liquid droplet in response to the magnetic field; and separating the aggregated magnetically responsive particles from the liquid droplet with the magnetic field, wherein the aggregated magnetically responsive particles move in response to the magnetic field to a location on the element array in proximity to the magnet element. Embodiments of the methods of the present application may be performed by an EWOD control system executing program code stored on a non-transitory computer readable medium.