scholarly journals Microparticle Inertial Focusing in an Asymmetric Curved Microchannel

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 57 ◽  
Author(s):  
Arzu Özbey ◽  
Mehrdad Karimzadehkhouei ◽  
Hossein Alijani ◽  
Ali Koşar

Inertial Microfluidics offer a high throughput, label-free, easy to design, and cost-effective solutions, and are a promising technique based on hydrodynamic forces (passive techniques) instead of external ones, which can be employed in the lab-on-a-chip and micro-total-analysis-systems for the focusing, manipulation, and separation of microparticles in chemical and biomedical applications. The current study focuses on the focusing behavior of the microparticles in an asymmetric curvilinear microchannel with curvature angle of 280°. For this purpose, the focusing behavior of the microparticles with three different diameters, representing cells with different sizes in the microchannel, was experimentally studied at flow rates from 400 to 2700 µL/min. In this regard, the width and position of the focusing band are carefully recorded for all of the particles in all of the flow rates. Moreover, the distance between the binary combinations of the microparticles is reported for each flow rate, along with the Reynolds number corresponding to the largest distances. Furthermore, the results of this study are compared with those of the microchannel with the same curvature angle but having a symmetric geometry. The microchannel proposed in this study can be used or further modified for cell separation applications.

Author(s):  
Arzu Özbey ◽  
Mehrdad Karimzadehkhouei ◽  
Hossein Alijani ◽  
Ali Koşar

Inertial microfluidics offers high throughput, label-free, easy to design, and cost-effective solutions and is a promising technique based on hydrodynamic forces (passive techniques) instead of external ones, which can be employed in lab-on-a-chip and micro-total-analysis-systems for focusing, manipulation, and separation of microparticles in chemical and biomedical applications. The current work, studies the focusing behavior of microparticles in an asymmetric curvilinear microchannel. For this purpose, focusing behavior, including position and band width, of microparticles of diameters of 10, 15 and 20 µm, which served as representatives of different cells, in an asymmetric curvilinear microchannel with curvature angle of 280° was experimentally studied at flow rates from 400 to 2700 µL/min (corresponding to Reynolds numbers between 30 and 205). The results revealed that the largest distance between focusing bands of 20 µm and 10 µm microparticles as well as between focusing bands of 15 µm and 10 µm was obtained at Reynolds number of 121. For the case of microparticles of diameters 20 µm and 15 µm, the largest distance was seen at Reynolds number of 144. The focusing band width became smaller in the asymmetric microchannel so that focusing could be more clearly observed in this configuration.


Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Kaan Erdem ◽  
Vahid Ebrahimpour Ahmadi ◽  
Ali Kosar ◽  
Lütfullah Kuddusi

Label-free, size-dependent cell-sorting applications based on inertial focusing phenomena have attracted much interest during the last decade. The separation capability heavily depends on the precision of microparticle focusing. In this study, five-loop spiral microchannels with a height of 90 µm and a width of 500 µm are introduced. Unlike their original spiral counterparts, these channels have elliptic configurations of varying initial aspect ratios, namely major axis to minor axis ratios of 3:2, 11:9, 9:11, and 2:3. Accordingly, the curvature of these configurations increases in a curvilinear manner through the channel. The effects of the alternating curvature and channel Reynolds number on the focusing of fluorescent microparticles with sizes of 10 and 20 µm in the prepared suspensions were investigated. At volumetric flow rates between 0.5 and 3.5 mL/min (allowing separation), each channel was tested to collect samples at the designated outlets. Then, these samples were analyzed by counting the particles. These curved channels were capable of separating 20 and 10 µm particles with total yields up to approximately 95% and 90%, respectively. The results exhibited that the level of enrichment and the focusing behavior of the proposed configurations are promising compared to the existing microfluidic channel configurations.


Author(s):  
Ivano Gregoratto ◽  
Calum J. McNeil ◽  
Michael W. Reeks

A planar micro-device capable of rapidly separating large volumes of dilute suspensions was designed and modelled using a commercial CFD package. The device consists of a single planar Archimedean spiral micro channel with a bifurcation at the exit. The device exploits small inertial and hydrodynamic differences between particles of dissimilar size, which arise as the sample is rapidly pumped through the device. The channel length and location of the bifurcation were found to affect the separation achievable by the devices. Devices of varying geometries were fabricated using conventional silicon micro fabrication processes and were tested by flowing dilute aqueous suspensions of polystyrene particles (diameters of 1μm, 8μm and 10μm) through the devices at various flow rates. A 3.5 fold concentration enhancement of 10μm particles was achieved in the longer devices at flow rates of 2 ml/min, whereas the 1μm particles showed negligible concentration increases at similar flow rates. The device may be used as a sample preparation stage in a complex μTAS, where rapid, continuous concentration of dilute suspensions is often required.


RSC Advances ◽  
2015 ◽  
Vol 5 (66) ◽  
pp. 53857-53864 ◽  
Author(s):  
Amy E. Reece ◽  
Kaja Kaastrup ◽  
Hadley D. Sikes ◽  
John Oakey

A staged microfluidic inertial focusing device capable of high-yield, high-throughput complex fluid enrichment has been developed for integrated microfluidic cellular assays and biological micro total analysis systems.


2003 ◽  
Vol 766 ◽  
Author(s):  
Vineet Sharma ◽  
Arief B. Suriadi ◽  
Frank Berauer ◽  
Laurie S. Mittelstadt

AbstractNormal photolithography tools have focal depth limitations and are unable to meet the expectations of high resolution photolithography on highly topographic structures. This paper shows a cost effective and promising technique of combining two different approaches to achieve critical dimensions of traces on slope pattern continuity on highly topographic structures. Electrophoretically deposited photoresist is used on 3-D structured wafers. This photoresist coating technique is fairly known in the MEMS industries to achieve uniform and conformal photoresist films on 3D surfaces. Multi step exposures are used to expose electrophoretically deposited photoresist. AlCu (Cu-0.5%), 0.47-0.53 μm thick metal film is deposited on 3D structured silicon substrate to plate photoresist. By combining these two novel methods, metal (AlCu) traces of 75 μm line width and 150 μm pitch (from top flat to down the slope) have been demonstrated on isotropically etched 350 μm deep trenches with 5-10% line width loss.


2020 ◽  
Vol 26 (40) ◽  
pp. 5188-5204
Author(s):  
Uzair Nagra ◽  
Maryam Shabbir ◽  
Muhammad Zaman ◽  
Asif Mahmood ◽  
Kashif Barkat

Nanosized particles, with a size of less than 100 nm, have a wide variety of applications in various fields of nanotechnology and biotechnology, especially in the pharmaceutical industry. Metal nanoparticles [MNPs] have been synthesized by different chemical and physical procedures. Still, the biological approach or green synthesis [phytosynthesis] is considered as a preferred method due to eco-friendliness, nontoxicity, and cost-effective production. Various plants and plant extracts have been used for the green synthesis of MNPs, including biofabrication of noble metals, metal oxides, and bimetallic combinations. Biomolecules and metabolites present in plant extracts cause the reduction of metal ions into nanosized particles by one-step preparation methods. MNPs have remarkable attractiveness in biomedical applications for their use as potential antioxidant, anticancer and antibacterial agents. The present review offers a comprehensive aspect of MNPs production via top-to-bottom and bottom-to-top approach with considerable emphasis on green technology and their possible biomedical applications. The critical parameters governing the MNPs formation by plant-based synthesis are also highlighted in this review.


Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 793
Author(s):  
Uroš Zupančič ◽  
Joshua Rainbow ◽  
Pedro Estrela ◽  
Despina Moschou

Printed circuit boards (PCBs) offer a promising platform for the development of electronics-assisted biomedical diagnostic sensors and microsystems. The long-standing industrial basis offers distinctive advantages for cost-effective, reproducible, and easily integrated sample-in-answer-out diagnostic microsystems. Nonetheless, the commercial techniques used in the fabrication of PCBs produce various contaminants potentially degrading severely their stability and repeatability in electrochemical sensing applications. Herein, we analyse for the first time such critical technological considerations, allowing the exploitation of commercial PCB platforms as reliable electrochemical sensing platforms. The presented electrochemical and physical characterisation data reveal clear evidence of both organic and inorganic sensing electrode surface contaminants, which can be removed using various pre-cleaning techniques. We demonstrate that, following such pre-treatment rules, PCB-based electrodes can be reliably fabricated for sensitive electrochemical biosensors. Herein, we demonstrate the applicability of the methodology both for labelled protein (procalcitonin) and label-free nucleic acid (E. coli-specific DNA) biomarker quantification, with observed limits of detection (LoD) of 2 pM and 110 pM, respectively. The proposed optimisation of surface pre-treatment is critical in the development of robust and sensitive PCB-based electrochemical sensors for both clinical and environmental diagnostics and monitoring applications.


RSC Advances ◽  
2015 ◽  
Vol 5 (31) ◽  
pp. 23990-23998 ◽  
Author(s):  
Gaoling Liang ◽  
Zhongjun Zhao ◽  
Yin Wei ◽  
Kunping Liu ◽  
Wenqian Hou ◽  
...  

A simple, label-free and cost-effective localized surface plasmon resonance (LSPR) immunosensing method was developed for detection of alpha-fetoprotein (AFP).


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