Magnetic Fields in Microfluidic Systems

A special issue of Magnetochemistry (ISSN 2312-7481).

Deadline for manuscript submissions: closed (30 September 2018) | Viewed by 18348

Special Issue Editors


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Guest Editor
Queensland Micro- and Nanotechnology Centre, Griffith University, West Creek Road, Nathan, QLD 4111, Australia
Interests: microfluidics; nanofluidics; micro/nanomachining technologies; micro/nanoscale science; instrumentation for biomedical applications
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Interests: magneto-microfluidics; nanofluidics; magnetohydrodynamics; computational fluid dynamics; accelerator in space

Special Issue Information

Dear Colleagues,

Among all the active actuation methods in microfluidic devices, magnetic fields have exhibited distinguished performance in instant and remote controllability without limitation on dielectric properties of the liquid. For the last few decades, the study of magnetic properties, for both solid and liquid materials, has attracted increasing attention, such as field generation by multifunctional electromagnets, magnetization of nanoparicles or microparticles, paramagnetic liquid, and so on. Interestingly, magneto microfluidics emerged at the fields of biological and biochemical devices, where the interaction among liquid, paramagnetic particles, diamagnetic cells, channel structure, and magnetization in general, and particularly the synchronization between particle migration and the localized magnetic moments, can lead to new phenomena and function and result in a high potential of technological applications, namely in sensors and actuators.

This Special Issue of Magnetochemistry aims to collect recent work devoted to the illustration of magnetically tunable properties or driven behavior in microfluidic devices, including but not limited to the configuration optimization, more comprehensive understanding on magnetization and flow, the span extension on versatile applications, namely in the topics listed below.

Prof. Dr. Nam-Trung Nguyen
Prof. Dr. Guiping Zhu
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Magnetic fields
  • Magnetization
  • Microfluidic device
  • Micro/mini channel
  • Fluid flow
  • Interfacial tension
  • Computational fluid dynamics
  • Magnetic applications

Published Papers (4 papers)

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Research

9 pages, 2914 KiB  
Article
Effects of Vertical Magnetohydrodynamic Flows on Chiral Surface Formation in Magnetoelectrolysis
by Iwao Mogi, Ryoichi Morimoto, Ryoichi Aogaki and Kohki Takahashi
Magnetochemistry 2018, 4(3), 40; https://doi.org/10.3390/magnetochemistry4030040 - 06 Sep 2018
Cited by 7 | Viewed by 3520
Abstract
Magnetoelectrolysis (electrolysis in magnetic fields) has potential to produce chiral surfaces on metal films. The Lorentz force causes two types of magnetohydrodynamic (MHD) flows; a vertical MHD flow and micro-MHD vortices, and the combination of these MHD flows has been considered to produce [...] Read more.
Magnetoelectrolysis (electrolysis in magnetic fields) has potential to produce chiral surfaces on metal films. The Lorentz force causes two types of magnetohydrodynamic (MHD) flows; a vertical MHD flow and micro-MHD vortices, and the combination of these MHD flows has been considered to produce chiral surfaces. This paper shows the effects of vertical MHD flow on the chiral surface formation in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. To control the vertical MHD flows the working electrode was embedded in a tube wall with various heights of 2–12 mm, and the vertical MHD flows were expected to penetrate into the tubes with damping. In both MED and MEE experiments, the surface chirality diminished considerably at the wall height of 12 mm. When the penetrating MHD flow could not reach the electrode surface in the sufficiently tall wall, such an MHD flow could not affect the micro-MHD vortices. These results demonstrate that the vertical MHD flow plays a significant role in symmetry breaking of micro-MHD vortices. Full article
(This article belongs to the Special Issue Magnetic Fields in Microfluidic Systems)
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17 pages, 4104 KiB  
Article
Supervised Learning to Predict Sperm Sorting by Magnetophoresis
by James Boon Yong Koh, Xinhui Shen and Marcos
Magnetochemistry 2018, 4(3), 31; https://doi.org/10.3390/magnetochemistry4030031 - 02 Jul 2018
Cited by 6 | Viewed by 4342
Abstract
Machine learning is gaining popularity in the commercial world, but its benefits are yet to be well-utilised by many in the microfluidics community. There is immense potential in bridging the gap between applied engineering and artificial intelligence as well as statistics. We illustrate [...] Read more.
Machine learning is gaining popularity in the commercial world, but its benefits are yet to be well-utilised by many in the microfluidics community. There is immense potential in bridging the gap between applied engineering and artificial intelligence as well as statistics. We illustrate this by a case study investigating the sorting of sperm cells for assisted reproduction. Slender body theory (SBT) is applied to compute the behavior of sperm subjected to magnetophoresis, with due consideration given to statistical variations. By performing computations on a small subset of the generated data, we train an ensemble of four supervised learning algorithms and use it to make predictions on the velocity of each sperm. Our results suggest that magnetophoresis can magnify the difference between normal and abnormal cells, such that a sorted sample has over twice the proportion of desirable cells. In addition, we demonstrated that the predictions from machine learning gave comparable results with significantly lower computational costs. Full article
(This article belongs to the Special Issue Magnetic Fields in Microfluidic Systems)
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17 pages, 2428 KiB  
Article
Numerical Study of Lateral Migration of Elliptical Magnetic Microparticles in Microchannels in Uniform Magnetic Fields
by Jie Zhang and Cheng Wang
Magnetochemistry 2018, 4(1), 16; https://doi.org/10.3390/magnetochemistry4010016 - 12 Feb 2018
Cited by 16 | Viewed by 5084
Abstract
This work reports numerical investigation of lateral migration of a paramagnetic microparticle of an elliptic shape in a plane Poiseuille flow of a Newtonian fluid under a uniform magnetic field by direct numerical simulation (DNS). A finite element method (FEM) based on the [...] Read more.
This work reports numerical investigation of lateral migration of a paramagnetic microparticle of an elliptic shape in a plane Poiseuille flow of a Newtonian fluid under a uniform magnetic field by direct numerical simulation (DNS). A finite element method (FEM) based on the arbitrary Lagrangian–Eulerian (ALE) approach is used to study the effects of strength and direction of the magnetic field, particle–wall separation distance and particle shape on the lateral migration. The particle is shown to exhibit negligible lateral migration in the absence of a magnetic field. When the magnetic field is applied, the particle migrates laterally. The migration direction depends on the direction of the external magnetic field, which controls the symmetry property of the particle rotational velocity. The magnitude of net lateral migration velocity over a π cycle is increased with the magnetic field strength when the particle is able to execute complete rotations, expect for α = 45° and 135°. By investigating a wide range of parameters, our direct numerical simulations yield a comprehensive understanding of the particle migration mechanism. Based on the numerical data, an empirical scaling relationship is proposed to relate the lateral migration distance to the asymmetry of the rotational velocity and lateral oscillation amplitude. The scaling relationship provides useful guidelines on design of devices to manipulate nonspherical micro-particles, which have important applications in lab-on-a-chip technology, biology and biomedical engineering. Full article
(This article belongs to the Special Issue Magnetic Fields in Microfluidic Systems)
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12 pages, 3499 KiB  
Article
Fabrication of Magnetically Driven Microvalve Arrays Using a Photosensitive Composite
by Tasuku Nakahara, Junya Suzuki, Yuki Hosokawa, Fusao Shimokawa, Hidetoshi Kotera and Takaaki Suzuki
Magnetochemistry 2018, 4(1), 7; https://doi.org/10.3390/magnetochemistry4010007 - 06 Jan 2018
Cited by 10 | Viewed by 4612
Abstract
Microvalves play an important role in fluid control in micro total analysis systems (µTAS). Previous studies have reported complex fabrication processes for making microvalve elements in a channel. Hence, there is a need for a simpler microvalve fabrication method for achieving throughput improvement [...] Read more.
Microvalves play an important role in fluid control in micro total analysis systems (µTAS). Previous studies have reported complex fabrication processes for making microvalve elements in a channel. Hence, there is a need for a simpler microvalve fabrication method for achieving throughput improvement and cost reduction in µTAS. In this study, we propose a simple fabrication method for a magnetically driven microvalve array using a photosensitive composite. The composite was prepared by mixing a photoresist and magnetic particles of pure iron. The simple fabrication process was performed by using a laminating layer composed of a sacrificial part and the composite in a channel. The microvalve elements were fabricated by one-step photolithography using the processability of the sacrificial layer and composite. Further, we demonstrated the magnetic driving property of the fabricated microvalve array device. Compared to devices containing non-driving microvalves, the flow rate was decreased by 50%, and the pressure difference between the inlet and outlet increased by up to 4 kPa with increase in driving microvalve elements. These results imply that our proposed device could be useful for practical µTAS applications. Full article
(This article belongs to the Special Issue Magnetic Fields in Microfluidic Systems)
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