Dielectrophoresis of micro/nano particles using curved microelectrodes

Abstract

Dielectrophoresis, the induced motion of polarisable particles in non-homogenous electric field, has been proven as a versatile mechanism to transport, immobilise, sort and characterise micro/nano scale particle in microfluidic platforms. The performance of dielectrophoretic (DEP) systems depend on two parameters: the configuration of microelectrodes designed to produce the DEP force and the operating strategies devised to employ this force in such processes. This work summarises the unique features of curved microelectrodes for the DEP manipulation of target particles in microfluidic systems. The curved microelectrodes demonstrate exceptional capabilities including (i) creating strong electric fields over a large portion of their structure, (ii) minimising electro-thermal vortices and undesired disturbances at their tips, (iii) covering the entire width of the microchannel influencing all passing particles, and (iv) providing a large trapping area at their entrance region, as evidenced by extensive numerical and experimental analyses. These microelectrodes have been successfully applied for a variety of engineering and biomedical applications including (i) sorting and trapping model polystyrene particles based on their dimensions, (ii) patterning carbon nanotubes to trap low-conductive particles, (iii) sorting live and dead cells based on their dielectric properties, (iv) real-time analysis of drug-induced cell death, and (v) interfacing tumour cells with environmental scanning electron microscopy to study their morphological properties. The DEP systems based on curved microelectrodes have a great potential to be integrated with the future lab-on-achip systems.

Three-dimensional printing of freeform helical microstructures: a review

“…Lab-on-a-chip systems: cell separators Highly efficient lab-on-a-chip systems, specically those used for the detection and separation of microparticles such as cells and viruses, have rapidly progressed through the miniaturization of components and the fabrication of smaller functional devices. [61][62][63] The miniaturization of these systems via the design and fabrication of complex 3D microuidic devices showed new functionality and increased performance. 61,62 Helical geometry has been recently used in the fabrication of highly efficient dielectrophoretic (DEP) cell separators in two different avenues: helical-shaped microelectrodes and helical-shaped microuidic channels.…”

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

“…With the low speeds involved to avoid leakage in the concertation of the sample, the flow of the medium was constant; the flow affects the output result of the DEP fields applied [21]. Additionally, it is a fast, low-voltage magnitude, and potentially low-cost method to extract measurements and to avoid hydrodynamic effects [19,48,49].…”

Sensitive quantification and visual detection of bacteria using CdSe/ZnS@SiO2 nanoparticles as fluorescent probes

“…In order to achieve a better visualization and detection of bacteria, the integrated DEP microuidic chip was proposed to capture and enrich the target bacteria. [25][26][27][28] Yang et al demonstrated that positive DEP could concentrate Listeria efficiently at the edges the interdigitated micro-electrodes from the ow in microuidic channels. 29 Therefore, bacteria visualizations were worth further study by using highly efficient uorescent markers and an integrated dielectrophoresis microuidic chip.…”