Continuous-Flow Cell Dipping and Medium Exchange in a Microdevice using Dielectrophoresis

Alhammadi, Falah; Waheed, Waqas; El‐Khasawneh, Bashar; Alazzam, Anas

doi:10.3390/mi9050223

Cited by 15 publications

(9 citation statements)

References 39 publications

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“…DEP has been extensively used in microfluidic systems for manipulating of particles and cells. The magnitude of the DEP force depends on the electrical properties, size, and shape of the particle, conductivity of the medium, and the frequency, non-uniformity, and amplitude of the AC signal [30]. As the force is linearly proportional to the term ∇||Erms2, one approach to enhance manipulation of cells using DEP is by increasing the spatial non-uniformity of the electric field [29,31,32].…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Porous Gold Film Using Graphene Oxide as a Sacrificial Layer

et al. 2019

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An original and simple fabrication process to produce thin porous metal films on selected substrates is reported. The fabrication process includes the deposition of a thin layer of gold on a substrate, spin coating of a graphene oxide dispersion, etching the gold film through the graphene oxide layer, and removing the graphene oxide layer. The porosity of the thin gold film is controlled by varying the etching time, the thickness of the gold film, and the concentration of the graphene oxide dispersion. Images by scanning electron and metallurgical microscopes show a continuous gold film with random porosity formed on the substrate with a porosity size ranging between hundreds of nanometers to tens of micrometers. This general approach enables the fabrication of porous metal films using conventional microfabrication techniques. The proposed process is implemented to fabricate electrodes with patterned porosity that are used in a microfluidic system to manipulate living cells under dielectrophoresis. Porous electrodes are found to enhance the magnitude and spatial distribution of the dielectrophoretic force.

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Section: Resultsmentioning

confidence: 99%

Fabrication of Porous Gold Film Using Graphene Oxide as a Sacrificial Layer

et al. 2019

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“…The microfluidic channel was fabricated from well-mixed polydimethylsiloxane (PDMS) elastomer and a curing agent (10:1), which was degassed in a vacuum chamber [43]. The mixture was then poured onto a microchannel and baked in a convective oven for 35 min at 100 °C.…”

Section: Methodsmentioning

confidence: 99%

Dielectrophoresis of Amyloid-Beta Proteins as a Microfluidic Template for Alzheimer’s Research

Al-Ahdal

Kayani

Ali

et al. 2019

IJMS

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We employed dielectrophoresis to a yeast cell suspension containing amyloid-beta proteins (Aβ) in a microfluidic environment. The Aβ was separated from the cells and characterized using the gradual dissolution of Aβ as a function of the applied dielectrophoretic parameters. We established the gradual dissolution of Aβ under specific dielectrophoretic parameters. Further, Aβ in the fibril form at the tip of the electrode dissolved at high frequency. This was perhaps due to the conductivity of the suspending medium changing according to the frequency, which resulted in a higher temperature at the tips of the electrodes, and consequently in the breakdown of the hydrogen bonds. However, those shaped as spheroidal monomers experienced a delay in the Aβ fibril transformation process. Yeast cells exposed to relatively low temperatures at the base of the electrode did not experience a positive or negative change in viability. The DEP microfluidic platform incorporating the integrated microtip electrode array was able to selectively manipulate the yeast cells and dissolve the Aβ to a controlled extent. We demonstrate suitable dielectrophoretic parameters to induce such manipulation, which is highly relevant for Aβ-related colloidal microfluidic research and could be applied to Alzheimer’s research in the future.

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“…The rGO film is patterned to create two electrodes which are then connected to an AC signal to generate inhomogeneous electric device using a syringe pump. The channel fabrication, medium and samples preparations, are detailed in [40][41][42]. Figure 5 shows the pDEP response of RBCs under an AC signal of 5 Vpp at 1 MHz.…”

Section: Living Cells Manipulationmentioning

confidence: 99%

Micro-Pattern of Graphene Oxide Films Using Metal Bonding

et al. 2020

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Recently, graphene has been explored in several research areas according to its outstanding combination of mechanical and electrical features. The ability to fabricate micro-patterns of graphene facilitates its integration in emerging technologies such as flexible electronics. This work reports a novel micro-pattern approach of graphene oxide (GO) film on a polymer substrate using metal bonding. It is shown that adding ethanol to the GO aqueous dispersion enhances substantially the uniformity of GO thin film deposition, which is a great asset for mass production. On the other hand, the presence of ethanol in the GO solution hinders the fabrication of patterned GO films using the standard lift-off process. To overcome this, the fabrication process provided in this work takes advantage of the chemical adhesion between the GO or reduced GO (rGO) and metal films. It is proved that the adhesion between the metal layer and GO or rGO is stronger than the adhesion between the latter and the polymer substrate (i.e., cyclic olefin copolymer used in this work). This causes the removal of the GO layer underneath the metal film during the lift-off process, leaving behind the desired GO or rGO micro-patterns. The feasibility and suitability of the proposed pattern technique is confirmed by fabricating the patterned electrodes inside a microfluidic device to manipulate living cells using dielectrophoresis. This work adds great value to micro-pattern GO and rGO thin films and has immense potential to achieve high yield production in emerging applications.

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Continuous-Flow Cell Dipping and Medium Exchange in a Microdevice using Dielectrophoresis

Cited by 15 publications

References 39 publications

Fabrication of Porous Gold Film Using Graphene Oxide as a Sacrificial Layer

Fabrication of Porous Gold Film Using Graphene Oxide as a Sacrificial Layer

Dielectrophoresis of Amyloid-Beta Proteins as a Microfluidic Template for Alzheimer’s Research

Micro-Pattern of Graphene Oxide Films Using Metal Bonding

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