scholarly journals An Experimental Study of 3D Electrode-Facilitated Particle Traffic Flow-Focusing Driven by Induced-Charge Electroosmosis

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 135 ◽  
Author(s):  
Tianyi Jiang ◽  
Ye Tao ◽  
Hongyuan Jiang ◽  
Weiyu Liu ◽  
Yansu Hu ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Yeast Cells ◽  
Bottom Surface ◽  
Flow Focusing ◽  
Electrode Strip ◽  
Geometry Configuration ◽  
Particle Stream ◽  
Induced Charge ◽  
Channel Bottom ◽  
3D Electrode

In this paper we present a novel microfluidic approach for continuous, rapid and switchable particle concentration, using induced-charge electroosmosis (ICEO) in 3D electrode layouts. Field-effect control on non-linear electroosmosis in the transverse direction greatly facilitates a selective concentration of biological yeast cells from a straight main microchannel into one of the three downstream branch channels in our microfluidic device. For the geometry configuration of 3D driving electrode plates on sidewalls and a 2D planar gate electrode strip on the channel bottom surface, we briefly describe the underlying physics of an ICEO-based particle flow-focusing method, and provide relevant simulation results to show how gate voltage amplitude can be used to guide the motion trajectory of the concentrated particle stream. With a relatively simple geometrical configuration, the proposed microfluidic device provides new possibilities to controllably concentrate micro/nanoparticles in continuous flow by using ICEO, and is suitable for a high-throughput front-end cell concentrator interfacing with various downstream biosensors.

scholarly journals A High-Throughput Electrokinetic Micromixer via AC Field-Effect Nonlinear Electroosmosis Control in 3D Electrode Configurations

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 432 ◽  
Author(s):  
Kai Du ◽  
Weiyu Liu ◽  
Yukun Ren ◽  
Tianyi Jiang ◽  
Jingni Song ◽  
...  
Keyword(s):  
Field Effect ◽  
Bottom Surface ◽  
Microfluidic Mixing ◽  
New Device ◽  
Experimental Parameters ◽  
Voltage Wave ◽  
Effect Transistor ◽  
Ac Field ◽  
Channel Bottom ◽  
3D Electrode

In this study, we make use of the AC field-effect flow control on induced-charge electroosmosis (ICEO), to develop an electrokinetic micromixer with 3D electrode layouts, greatly enhancing the device performance compared to its 2D counterpart of coplanar metal strips. A biased AC voltage wave applied to the central gate terminal, i.e., AC field-effect control, endows flow field-effect-transistor of ICEO the capability to produce arbitrary symmetry breaking in the transverse electrokinetic vortex flow pattern, which makes it fascinating for microfluidic mixing. Using the Debye-Huckel approximation, a mathematical model is established to test the feasibility of the new device design in stirring nanoparticle samples carried by co-flowing laminar streams. The effect of various experimental parameters on constructing a viable micromixer is investigated, and an integrated microdevice with a series of gate electrode bars disposed along the centerline of the channel bottom surface is proposed for realizing high-flux mixing. Our physical demonstration on field-effect nonlinear electroosmosis control in 3D electrode configurations provides useful guidelines for electroconvective manipulation of nanoscale objects in modern microfluidic systems.

Continuous-flow focusing of microparticles using induced-charge electroosmosis in a microfluidic device with 3D AgPDMS electrodes

RSC Advances ◽  
2015 ◽  
Vol 5 (82) ◽  
pp. 66602-66610 ◽  
Author(s):  
Yankai Jia ◽  
Yukun Ren ◽  
Hongyuan Jiang
Keyword(s):  
Microfluidic Device ◽  
Continuous Flow ◽  
Alternating Current ◽  
Flow Focusing ◽  
Negative Effects ◽  
Induced Charge

Efficient continuous-flow focusing of microparticles using induced-charge electroosmosis is presented and 3D AgPDMS electrodes are employed to avoid the negative effects of alternating current electroosmosis and dielectrophoresis.

scholarly journals Negative Pressure Provides Simple and Stable Droplet Generation in a Flow-Focusing Microfluidic Device

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 662
Author(s):  
Nikita A. Filatov ◽  
Anatoly A. Evstrapov ◽  
Anton S. Bukatin
Keyword(s):  
Microfluidic Device ◽  
Negative Pressure ◽  
Low Cost ◽  
Control Valve ◽  
Droplet Microfluidics ◽  
Droplet Generation ◽  
Electric Signal ◽  
Absolute Pressure ◽  
Flow Focusing ◽  
Wide Range

Droplet microfluidics is an extremely useful and powerful tool for industrial, environmental, and biotechnological applications, due to advantages such as the small volume of reagents required, ultrahigh-throughput, precise control, and independent manipulations of each droplet. For the generation of monodisperse water-in-oil droplets, usually T-junction and flow-focusing microfluidic devices connected to syringe pumps or pressure controllers are used. Here, we investigated droplet-generation regimes in a flow-focusing microfluidic device induced by the negative pressure in the outlet reservoir, generated by a low-cost mini diaphragm vacuum pump. During the study, we compared two ways of adjusting the negative pressure using a compact electro-pneumatic regulator and a manual airflow control valve. The results showed that both types of regulators are suitable for the stable generation of monodisperse droplets for at least 4 h, with variations in diameter less than 1 µm. Droplet diameters at high levels of negative pressure were mainly determined by the hydrodynamic resistances of the inlet microchannels, although the absolute pressure value defined the generation frequency; however, the electro-pneumatic regulator is preferable and convenient for the accurate control of the pressure by an external electric signal, providing more stable pressure, and a wide range of droplet diameters and generation frequencies. The method of droplet generation suggested here is a simple, stable, reliable, and portable way of high-throughput production of relatively large volumes of monodisperse emulsions for biomedical applications.

scholarly journals The Combined Effects of Co-Culture and Substrate Mechanics on 3D Tumor Spheroid Formation within Microgels Prepared via Flow-Focusing Microfluidic Fabrication

Pharmaceutics ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 229 ◽  
Author(s):  
Dongjin Lee ◽  
Chaenyung Cha
Keyword(s):  
Mechanical Properties ◽  
Cell Culture ◽  
Microfluidic Device ◽  
3D Cell Culture ◽  
Breast Adenocarcinoma ◽  
Adherent Cell ◽  
Flow Focusing ◽  
Spheroid Formation ◽  
3D Scaffold ◽  
Tumor Spheroids

Tumor spheroids are considered a valuable three dimensional (3D) tissue model to study various aspects of tumor physiology for biomedical applications such as tissue engineering and drug screening as well as basic scientific endeavors, as several cell types can efficiently form spheroids by themselves in both suspension and adherent cell cultures. However, it is more desirable to utilize a 3D scaffold with tunable properties to create more physiologically relevant tumor spheroids as well as optimize their formation. In this study, bioactive spherical microgels supporting 3D cell culture are fabricated by a flow-focusing microfluidic device. Uniform-sized aqueous droplets of gel precursor solution dispersed with cells generated by the microfluidic device are photocrosslinked to fabricate cell-laden microgels. Their mechanical properties are controlled by the concentration of gel-forming polymer. Using breast adenocarcinoma cells, MCF-7, the effect of mechanical properties of microgels on their proliferation and the eventual spheroid formation was explored. Furthermore, the tumor cells are co-cultured with macrophages of fibroblasts, which are known to play a prominent role in tumor physiology, within the microgels to explore their role in spheroid formation. Taken together, the results from this study provide the design strategy for creating tumor spheroids utilizing mechanically-tunable microgels as 3D cell culture platform.

3D FOCALIZATION MICROFLUIDIC DEVICE BUILT WITH LTCC TECHNOLOGY FOR NANOPARTICLE GENERATION USING NANOPRECIPITATION ROUTE

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000275-000280 ◽  
Author(s):  
Houari Cobas Gomez ◽  
Mario Ricardo Gongora-Rubio ◽  
Bianca Oliveira Agio ◽  
Vanessa Tiemi Kimura ◽  
Adriano Marim de Oliveira ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Chemical Process ◽  
Chemical Processes ◽  
Polydispersity Index ◽  
Flow Focusing ◽  
Enabling Technology ◽  
Fine Chemistry ◽  
Excellent Control ◽  
Microsystem Technologies ◽  
Nanoparticle Generation

Nanoprecipitation is a nanonization technique used for nanoparticle generation. Several fields, like pharmacology and fine chemistry, make use of such technique. Typically are used a bulky batch mechanical processes rendering high polydispersity index of generated nanoparticles, poorly particle size reproducibility and energy wasting. LTCC-based microsystem technologies allow the implementation of different unitary operations for chemical process, making it an enabling technology for the miniaturization of chemical processes. In fact, recently LTCC microfluidic reactors have been used to produce micro and nanoparticles with excellent control of size distribution and morphology. The present work provides a report on the performance of a 3D LTCC flow focusing Microfluidic device designed to fabricate polymeric nanocapsules for Hydrocortisone drug encapsulation, using nanoprecipitation route. Monodisperse Hydrocortisone nanocapsules were obtained with sizes (Tp) from 188.9 nm to 459.1 nm with polydispersity index (PDI) from 0.102 to 0.235.

scholarly journals Droplet Generation in a Flow-Focusing Microfluidic Device with External Mechanical Vibration

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 743
Author(s):  
Zhaoqin Yin ◽  
Zemin Huang ◽  
Xiaohui Lin ◽  
Xiaoyan Gao ◽  
Fubing Bao
Keyword(s):  
Microfluidic Device ◽  
Vibration Frequency ◽  
Linear Correlation ◽  
Vibration Amplitude ◽  
Mechanical Vibration ◽  
Droplet Generation ◽  
Flow Focusing ◽  
Generation Frequency ◽  
External Vibration ◽  
Shrinkage Process

The demand for highly controllable droplet generation methods is very urgent in the medical, materials, and food industries. The droplet generation in a flow-focusing microfluidic device with external mechanical vibration, as a controllable droplet generation method, is experimentally studied. The effects of vibration frequency and acceleration amplitude on the droplet generation are characterized. The linear correlation between the droplet generation frequency and the external vibration frequency and the critical vibration amplitude corresponding to the imposing vibration frequency are observed. The droplet generation frequency with external mechanical vibration is affected by the natural generation frequency, vibration frequency, and vibration amplitude. The droplet generation frequency in a certain microfluidic device with external vibration is able to vary from the natural generation frequency to the imposed vibration frequency at different vibration conditions. The evolution of dispersed phase thread with vibration is remarkably different with the process without vibration. Distinct stages of expansion, shrinkage, and collapse are observed in the droplet formation with vibration, and the occurrence number of expansion–shrinkage process is relevant with the linear correlation coefficient.

Formation of Copolymer-Ag Nanoparticles Composite Micelles in Three-dimensional Co-flow Focusing Microfluidic Device

2019 ◽  
Vol 34 (6) ◽  
pp. 1259-1265
Author(s):  
Mengran Feng ◽  
Guangyao He ◽  
Si Yi ◽  
Weizheng Song ◽  
Yanjun Chen ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Ag Nanoparticles ◽  
Three Dimensional ◽  
Flow Focusing

scholarly journals Closed-loop feedback control of microbubble diameter from a flow-focusing microfluidic device

2020 ◽  
Vol 14 (3) ◽  
pp. 034101
Author(s):  
Yanjun Xie ◽  
Adam J. Dixon ◽  
J. M. Robert Rickel ◽  
Alexander L. Klibanov ◽  
John A. Hossack
Keyword(s):  
Feedback Control ◽  
Microfluidic Device ◽  
Closed Loop ◽  
Flow Focusing ◽  
Loop Feedback ◽  
Closed Loop Feedback
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