Microarray Dot Electrodes Utilizing Dielectrophoresis for Cell Characterization

Abstract

During the last three decades; dielectrophoresis (DEP) has become a vital tool for cell manipulation and characterization due to its non-invasiveness. It is very useful in the trend towards point-of-care systems. Currently, most efforts are focused on using DEP in biomedical applications, such as the spatial manipulation of cells, the selective separation or enrichment of target cells, high-throughput molecular screening, biosensors and immunoassays. A significant amount of research on DEP has produced a wide range of microelectrode configurations. In this paper; we describe the microarray dot electrode, a promising electrode geometry to characterize and manipulate cells via DEP. The advantages offered by this type of microelectrode are also reviewed. The protocol for fabricating planar microelectrodes using photolithography is documented to demonstrate the fast and cost-effective fabrication process. Additionally; different state-of-the-art Lab-on-a-Chip (LOC) devices that have been proposed for DEP applications in the literature are reviewed. We also present our recently designed LOC device, which uses an improved microarray dot electrode configuration to address the challenges facing other devices. This type of LOC system has the capability to boost the implementation of DEP technology in practical settings such as clinical cell sorting, infection diagnosis, and enrichment of particle populations for drug development.

Dielectrophoretic Manipulation and Separation of Microparticles Using Microarray Dot Electrodes

“…The magnitude of the particle movement and the direction of this movement depend on the relative polarizabilities of the particles and the surrounding medium [22]. For a spherical particle of radius r , the DEP force is defined as: $\langle {\overrightarrow{F}}_{\mathit{\text{DEP}}}\rangle =2\pi r^3{\mathrm{italic\epsilon }}_o{\mathrm{italic\epsilon }}_{m}Re[K(\omega )]\nabla E^2$where ε o and ε m represent the permittivity values of the free space and the relative permittivity of the surrounding medium, respectively; ∇ E denotes the electric field gradient; and Re[ K (ω)] is the real part of the Clausius-Mossotti factor.…”

“…For example, when ${\mathit{\epsilon }}_P^{*}$ is higher than ${\mathit{\epsilon }}_m^{*}$, the Re[K(ω)] sign is positive, and the particles experience p-DEP and travel towards the higher electric field gradient region. On the contrary, when ${\mathit{\epsilon }}_P^{*}$ is lower than ${\mathit{\epsilon }}_m^{*}$, the Re[ K (ω)] sign is negative, and the particles travel towards the low electric field gradient region, experiencing n-DEP effect [22]. …”

Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

“…The non-uniform field can be created by applying voltage across geometrical electrodes [67], by placing an insulator between electrodes [68,69] or even electrodeless [70,71]. …”

Fabrication of a Cell Electrostimulator Using Pulse Laser Deposition and Laser Selective Thin Film Removal

“…Too overlapping will deliver too much energy over the glass, resulting on damage at surface, while low overlapping will result on inefficient material removal. In Figure 5 are presented some samples of tracks of a 200 nm aluminum layer ablated with different frequencies (10,12, and 14 KHz) and scan speeds (60 and 100 mm/s), and therefore with different pulse overlapping.…”

“…Most of them are fabricated using standard photolithography [12] because this technique is more versatile and allows the preparation of electrodes with a broad range of shapes and sizes, both single electrodes and the electrode arrays. However, photolithography technique needs usually about 3 h to fabricate planar electrodes, and it demands the use of several components in various steps and the final use of chemical components to remove the additional film.…”