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

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.

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 135 ◽  
Author(s):  
Tianyi Jiang ◽  
Ye Tao ◽  
Hongyuan Jiang ◽  
Weiyu Liu ◽  
Yansu Hu ◽  
...  

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.


Lab on a Chip ◽  
2016 ◽  
Vol 16 (15) ◽  
pp. 2803-2812 ◽  
Author(s):  
Yukun Ren ◽  
Jiangwei Liu ◽  
Weiyu Liu ◽  
Qi Lang ◽  
Ye Tao ◽  
...  

We propose a novel continuous-flow microfluidic particle concentrator with a specified focusing-particle number ratio (FR) at different channel outlets using induced-charge electroosmosis (ICEO).


Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 662
Author(s):  
Nikita A. Filatov ◽  
Anatoly A. Evstrapov ◽  
Anton S. Bukatin

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.


Pharmaceutics ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 229 ◽  
Author(s):  
Dongjin Lee ◽  
Chaenyung Cha

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.


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 ◽  
...  

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.


Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 743
Author(s):  
Zhaoqin Yin ◽  
Zemin Huang ◽  
Xiaohui Lin ◽  
Xiaoyan Gao ◽  
Fubing Bao

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.


2019 ◽  
Vol 34 (6) ◽  
pp. 1259-1265
Author(s):  
Mengran Feng ◽  
Guangyao He ◽  
Si Yi ◽  
Weizheng Song ◽  
Yanjun Chen ◽  
...  

Lab on a Chip ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 2373-2382 ◽  
Author(s):  
Paria Coliaie ◽  
Manish S. Kelkar ◽  
Nandkishor K. Nere ◽  
Meenesh R. Singh

While the conventional screening techniques suffer from depletion of supersaturation, the continuous-flow microfluidic device screens crystalline materials at controlled supersaturation.


Soft Matter ◽  
2018 ◽  
Vol 14 (6) ◽  
pp. 1056-1066 ◽  
Author(s):  
Cunlu Zhao ◽  
Chun Yang

In this work, we report an effective microfluidic technique for continuous-flow trapping and localized enrichment of micro- and nano-particles by using induced-charge electrokinetic (ICEK) phenomena.


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