High-throughput dielectrophoretic filtration of sub-micron and micro particles in macroscopic porous materials
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RESEARCH PAPER
High-throughput dielectrophoretic filtration of sub-micron and micro particles in macroscopic porous materials Malte Lorenz 1 & Daniel Malangré 2 & Fei Du 1 & Michael Baune 1 & Jorg Thöming 1,3 & Georg R. Pesch 1,3 Received: 31 October 2019 / Revised: 22 February 2020 / Accepted: 27 February 2020 # The Author(s) 2020
Abstract State-of-the-art dielectrophoretic (DEP) separation techniques provide unique properties to separate particles from a liquid or particles with different properties such as material or morphology from each other. Such separators do not operate at throughput that is sufficient for a vast fraction of separation tasks. This limitation exists because high electric field gradients are required to drive the separation which are generated by electrode microstructures that limit the maximum channel size. Here, we investigate DEP filtration, a technique that uses open porous microstructures instead of microfluidic devices to easily increase the filter cross section and, therefore, also the processable throughput by several orders of magnitude. Previously, we used simple microfluidic porous structures to derive design rules predicting the influence of key parameters on DEP filtration in real complex porous filters. Here, we study in depth DEP filtration in microporous ceramics and underpin the previously postulated dependencies by a broad parameter study (Lorenz et al., 2019). We will further verify our previous claim that the main separation mechanism is indeed positive DEP trapping by showing that we can switch from positive to negative DEP trapping when we increase the electric conductivity of the suspension. Two clearly separated trapping mechanisms (positive and negative DEP trapping) at different conductivities can be observed, and the transition between them matches theoretical predictions. This lays the foundation for selective particle trapping, and the results are a major step towards DEP filtration at high throughput to solve existing separation problems such as scrap recovery or cell separation in liquid biopsy.
Keywords Dielectrophoresis . Micron and sub-micron particle separation . Material-selective particle filtration . Open porous ceramic microstructures
Introduction
Published in the topical collection Bioanalytics and Higher Order Electrokinetics with guest editors Mark A. Hayes and Federica Caselli. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00216-020-02557-0) contains supplementary material, which is available to authorized users. * Georg R. Pesch [email protected] 1
Chemical Process Engineering (CVT), University of Bremen, Leobener Str. 6, 28359 Bremen, Germany
2
Center of Applied Space Technology and Microgravity (ZARM), University of Bremen, Am Fallturm 2, 28359 Bremen, Germany
3
MAPEX Center for Materials and Processes, University of Bremen, 330 440, 28334 Bremen, Germany
Separation of micron and sub-micron particles from liquid media or according to their properties is essential for a wide variety of
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