Active Colloidal and Micro Systems for Propulsion and Manipulation

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "E:Engineering and Technology".

Deadline for manuscript submissions: 31 May 2024 | Viewed by 5912

Special Issue Editors

Liaoning Key Laboratory of Marine Sensing and Intelligent Detection, Department of Information Science and Technology, Dalian Maritime University, Dalian 116026, China
Interests: dielectrophoresis; microfluidics and nanofluidics; Lab on a chip; microplastics; soft materials and interfaces; biosensor; particle manipulation and separation; biological cell characterization

E-Mail Website
Guest Editor
Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
Interests: microfluidics; micro-/nanofabrication; smart materials; surface modification; biomimetic sensors and systems
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Colloidal suspensions are heterogeneous fluids containing solid microscopic particles. They play a crucial role in our everyday life, from the food and pharmaceutical industries to medicine and nanotechnology. The colloidal suspensions include two major classes: equilibrium and active, i.e., maintained out of thermodynamic equilibrium by external electric or magnetic fields, light, chemical reactions, or hydrodynamic shear flow. Due to the remarkable properties of converting available energy sources into directed propulsion and the capability of dynamic self-assembly into complex functional geometry, active colloidal suspensions are fabricated for the application of tunable self-assembled micro-swimmers and micro-robots. To precisely control and manipulate these micro/nanoscale targets and objects, the microsystem, including microfluidic and nanofluidic platforms, provides a powerful and promising technique for their potential in the fields of chemical, biological, and environmental science. Accordingly, this Special Issue seeks to showcase research papers, communications, and review articles that focus on novel methodological developments for the generation, fabrication, and utilization of active colloidal suspensions in a variety formats, with particular interest being paid to techniques for self-propulsion micro-swimmers and micro-robots as well as the manipulation, separation, characterization, and identification of micro/nanoscale particles and targets in micron systems.

Dr. Kai Zhao
Dr. Kaihuan Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 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

  • active colloidal
  • stimuli-responsive materials
  • micro-swimmers
  • manipulation and separation
  • dielectrophoresis
  • microfluidics
  • micro-/nanofabrication
  • micro systems

Published Papers (4 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

12 pages, 1574 KiB  
Article
Anisotropic Diffusion of Elongated Particles in Active Coherent Flows
by Dongdong Li, Yanan Liu, Hao Luo and Guangyin Jing
Micromachines 2024, 15(2), 199; https://doi.org/10.3390/mi15020199 - 28 Jan 2024
Viewed by 648
Abstract
The study of particle diffusion, a classical conundrum in scientific inquiry, holds manifold implications for various real-world applications. Particularly within the domain of active flows, where the motion of self-propelled particles instigates fluid movement, extensive research has been dedicated to unraveling the dynamics [...] Read more.
The study of particle diffusion, a classical conundrum in scientific inquiry, holds manifold implications for various real-world applications. Particularly within the domain of active flows, where the motion of self-propelled particles instigates fluid movement, extensive research has been dedicated to unraveling the dynamics of passive spherical particles. This scrutiny has unearthed intriguing phenomena, such as superdiffusion at brief temporal scales and conventional diffusion at longer intervals. In contrast to the spherical counterparts, anisotropic particles, which manifest directional variations, are prevalent in nature. Although anisotropic behavior in passive fluids has been subject to exploration, enigmatic aspects persist in comprehending the interplay of anisotropic particles within active flows. This research delves into the intricacies of anisotropic passive particle diffusion, exposing a notable escalation in translational and rotational diffusion coefficients, as well as the superdiffusion index, contingent upon bacterial concentration. Through a detailed examination of particle coordinates, the directional preference of particle diffusion is not solely dependent on the particle length, but rather determined by the ratio of the particle length to the associated length scale of the background flow field. These revelations accentuate the paramount importance of unraveling the nuances of anisotropic particle diffusion within the context of active flows. Such insights not only contribute to the fundamental understanding of particle dynamics, but also have potential implications for a spectrum of applications. Full article
(This article belongs to the Special Issue Active Colloidal and Micro Systems for Propulsion and Manipulation)
Show Figures

Figure 1

12 pages, 3372 KiB  
Article
Entropy by Neighbor Distance as a New Measure for Characterizing Spatiotemporal Orders in Microscopic Collective Systems
by Yulei Fu, Zongyuan Wu, Sirui Zhan, Jiacheng Yang, Gaurav Gardi, Vimal Kishore, Paolo Malgaretti and Wendong Wang
Micromachines 2023, 14(8), 1503; https://doi.org/10.3390/mi14081503 - 26 Jul 2023
Viewed by 934
Abstract
Collective systems self-organize to form globally ordered spatiotemporal patterns. Finding appropriate measures to characterize the order in these patterns will contribute to our understanding of the principles of self-organization in all collective systems. Here we examine a new measure based on the entropy [...] Read more.
Collective systems self-organize to form globally ordered spatiotemporal patterns. Finding appropriate measures to characterize the order in these patterns will contribute to our understanding of the principles of self-organization in all collective systems. Here we examine a new measure based on the entropy of the neighbor distance distributions in the characterization of collective patterns. We study three types of systems: a simulated self-propelled boid system, two active colloidal systems, and one centimeter-scale robotic swarm system. In all these systems, the new measure proves sensitive in revealing active phase transitions and in distinguishing steady states. We envision that the entropy by neighbor distance could be useful for characterizing biological swarms such as bird flocks and for designing robotic swarms. Full article
(This article belongs to the Special Issue Active Colloidal and Micro Systems for Propulsion and Manipulation)
Show Figures

Figure 1

10 pages, 3051 KiB  
Article
Dielectrophoresis-Based Selective Droplet Extraction Microfluidic Device for Single-Cell Analysis
by Seito Shijo, Daiki Tanaka, Tetsushi Sekiguchi, Jun-ichi Ishihara, Hiroki Takahashi, Masashi Kobayashi and Shuichi Shoji
Micromachines 2023, 14(3), 706; https://doi.org/10.3390/mi14030706 - 22 Mar 2023
Viewed by 1873
Abstract
We developed a microfluidic device that enables selective droplet extraction from multiple droplet-trapping pockets based on dielectrophoresis. The device consists of a main microchannel, five droplet-trapping pockets with side channels, and drive electrode pairs appropriately located around the trapping pockets. Agarose droplets capable [...] Read more.
We developed a microfluidic device that enables selective droplet extraction from multiple droplet-trapping pockets based on dielectrophoresis. The device consists of a main microchannel, five droplet-trapping pockets with side channels, and drive electrode pairs appropriately located around the trapping pockets. Agarose droplets capable of encapsulating biological samples were successfully trapped in the trapping pockets due to the difference in flow resistance between the main and side channels. Target droplets were selectively extracted from the pockets by the dielectrophoretic force generated between the electrodes under an applied voltage of 500 V. During their extraction from the trapping pockets, the droplets and their contents were exposed to an electric field for 400–800 ms. To evaluate whether the applied voltage could potentially damage the biological samples, the growth rates of Escherichia coli cells in the droplets, with and without a voltage applied, were compared. No significant difference in the growth rate was observed. The developed device enables the screening of encapsulated single cells and the selective extraction of target droplets. Full article
(This article belongs to the Special Issue Active Colloidal and Micro Systems for Propulsion and Manipulation)
Show Figures

Figure 1

13 pages, 3609 KiB  
Article
DC-Dielectrophoretic Manipulation and Isolation of Microplastic Particle-Treated Microalgae Cells in Asymmetric-Orifice-Based Microfluidic Chip
by Tianbo Gao, Kai Zhao, Jiaqi Zhang and Kaihuan Zhang
Micromachines 2023, 14(1), 229; https://doi.org/10.3390/mi14010229 - 16 Jan 2023
Cited by 3 | Viewed by 1823
Abstract
A novel direct-current dielectrophoretic (DC–DEP) method is proposed for the manipulation and isolation of microplastic particle (MP)-treated microalgae cells according to their dielectric properties in a microfluidic chip. The lateral migration and trajectory of the microalgae cells were investigated. To induce stronger DC–DEP [...] Read more.
A novel direct-current dielectrophoretic (DC–DEP) method is proposed for the manipulation and isolation of microplastic particle (MP)-treated microalgae cells according to their dielectric properties in a microfluidic chip. The lateral migration and trajectory of the microalgae cells were investigated. To induce stronger DC–DEP effects, a non-homogeneous electric-field gradient was generated by applying the DC electric voltages through triple pairs of asymmetric orifices with three small orifices and one large orifice located on the opposite microchannel wall across the whole channel, leading to the enhanced magnitude of the non-uniform electric-field gradient and effective dielectrophoretic area. The effects of the applied voltage, the polystyrene (PS) adsorption coverage, and thickness on the DC–DEP behaviors and migration were numerically investigated, and it was found that the effect of the PS adsorption thickness of the Chlorella cells on the DC–DEP behaviors can be neglected, but the effect on their trajectory shifts cannot. In this way, the separation of 3 µm and 6 µm Chlorella coated with 100% PS particles and the isolation of the Chlorella cells from those coated with various coverages and thicknesses of PS particles was successfully achieved, providing a promising method for the isolation of microalgae cells and the removal of undesired cells from a target suspension. Full article
(This article belongs to the Special Issue Active Colloidal and Micro Systems for Propulsion and Manipulation)
Show Figures

Figure 1

Back to TopTop