dielectrophoresis

Small extracellular vesicles (sEVs) reflect the genotype and phenotype of original cells and are biomarkers for early diagnosis and treatment monitoring of tumors. Yet, their small size and low density make them difficult to isolate and detect in body fluid samples. This study proposes a novel acDEP-Exo chip filled with transparent micro-beads, which formed a non-uniform electrical field, and finally achieved rapid, sensitive, and tunable sEVs capture and detection. The method requires only 20-50 μL of sample, achieved a limit of detection (LOD) of 161 particles/μL, and can detect biomarkers within 13 min...

Dielectrophoresis (DEP), which arises from the interaction between dielectric particles and an aqueous solution in a nonuniform electric field, contributes to the manipulation of nano and microparticles in many fields, including colloid physics, analytical chemistry, molecular biology, clinical medicine, and pharmaceutics. The measurement of the DEP force could provide a more complete solution for verifying current classical DEP theories. This review reports various imaging, fluidic, optical, and mechanical approaches for measuring the DEP forces at different amplitudes and frequencies...

Human mesenchymal stem cells (hMSCs) have gained traction in transplantation therapy due to their immunomodulatory, paracrine, immune-evasive, and multipotent differentiation potential. The inherent heterogeneity of hMSCs poses a challenge for therapeutic treatments and necessitates the identification of robust biomarkers to ensure reproducibility in both in vivo and in vitro experiments. In this study, we utilized dielectrophoresis (DEP), a label-free electrokinetic phenomenon, to investigate the heterogeneity of hMSCs derived from bone marrow (BM) and adipose tissue (AD)...

Type 2 diabetes mellitus (T2DM) is a prevalent and debilitating disease with numerous health risks, including cardiovascular diseases, kidney dysfunction, and nerve damage. One important aspect of T2DM is its association with the abnormal morphology of red blood cells (RBCs), which leads to increased blood viscosity and impaired blood flow. Therefore, evaluating the mechanical properties of RBCs is crucial for understanding the role of T2DM in cellular deformability. This provides valuable insights into disease progression and potential diagnostic applications...

A novel optically induced dielectrophoresis (ODEP) system that can operate under flow conditions is designed for automatic trapping of cells and subsequent induction of 2D multi-frequency cell trajectories. Like in a "ping-pong" match, two virtual electrode barriers operate in an alternate mode with varying frequencies of the input voltage. The so-derived cell motions are characterized via time-lapse microscopy, cell tracking, and state-of-the-art machine learning algorithms, like the wavelet scattering transform (WST)...

Nano/microfluidic-based nucleic acid tests have been proposed as a rapid and reliable diagnostic technology. Two key steps for many of these tests are target nucleic acid (NA) immobilization followed by an enzymatic reaction on the captured NAs to detect the presence of a disease-associated sequence. NA capture within a geometrically confined volume is an attractive alternative to NA surface immobilization that eliminates the need for sample pre-treatment ( e.g. label-based methods such as lateral flow assays) or use of external actuators ( e...

Exosomes, with diameters ranging from 30 to 150 nm, are saucer-shaped extracellular vesicles (EVs) secreted by various type of human cells. They are present in virtually all bodily fluids. Owing to their abundant nucleic acid and protein content, exosomes have emerged as promising biomarkers for noninvasive molecular diagnostics. However, the need for exosome separation purification presents tremendous technical challenges due to their minuscule size. In recent years, microfluidic technology has garnered substantial interest as a promising alternative capable of excellent separation performance, reduced reagent consumption, and lower overall device and operation costs...

Dielectrophoresis is a potential candidate for aligning nanorods on electrodes, in which the interplay between electric fields and microfluidics is critically associated with its yield. Despite much of previous work on dielectrophoresis, the impact of frequency modulation on dielectrophoresis-driven nanowire self-assembly is insufficiently understood. In this work, we systematically explore the frequency dependence of the self-alignment of silicon nanowires using a microfluidic channel. We vary the frequency from 1kHz to 1000kHz and analyze the resulting alignments in conjunction with numerical analysis...

There are many applications where upstream sample processing is required to concentrate dispersed particles in flow; this may be to increase the concentration (e.g., to enhance biosensor accuracy) or to decrease it (e.g., by removing contaminants from flow). The AC electrokinetic phenomenon, dielectrophoresis (DEP), has been used widely for particle trapping for flow, but the magnitude of the force drops reduces rapidly with distance from electrode edges, so that nm-scale particles such as viruses and bacteria are only trapped when near the electrode surface...

Microfluidic technology has great advantages in the precise manipulation of micro-nano particles, and the hybrid microfluidic separation technology has attracted much attention due to the advantages of both active and passive separation technology at the same time. In this paper, the hydrophoresis sorting technique is combined with the dielectrophoresis technique, and a dielectrophoresis-assisted hydrophoresis microdevice is studied to separate blood cells. By using the dielectrophoresis force to change the suspension position of the cells in the channel, the scope of the hydrophoresis device for sorting particles is expanded...

[This retracts the article DOI: 10.1155/2020/5358181.].

High-efficient separation of (bio)microparticles has important applications in chemical analysis, environmental monitoring, drug screening, and disease diagnosis and treatment. As a label-free and high-precision separation scheme, dielectrophoresis (DEP) has become a research hotspot in microparticle separation, especially for biological cells. When processing cells with DEP, relatively high electric conductivities of suspending media are sometimes required to maintain the biological activities of the biosample, which results in high temperature rises within the system caused by Joule heating...

The manipulation of single particles remains a topic of interest with many applications. Here we characterize the impact of selected parameters on the motion of single particles thanks to dielectrophoresis (DEP) induced by visible light, in a technique called Light-induced Dielectrophoresis, or LiDEP, also known as optoelectronic tweezers, optically induced DEP, and image-based DEP. Baker's yeast and Candida cells are exposed to an electric field gradient enabled by shining a photoconductive material with a specific pattern of visible light, and their response is measured in terms of the average cell velocity towards the gradient...

The presented study demonstrates the capability of the template-based electrokinetic assembly (TEA) and guidance to manipulate and capture individual biological cells within a microfluidic platform. Specifically, dielectrophoretic (DEP) focusing of K-562 cells towards lithographically-defined "wells" on the microelectrodes and positioning singles cells withing these "wells" was demonstrated. K-562 lymphoblast cells, are widely used in immunology research. The DEP guidance, particularly involving positive DEP (pDEP), enables the controlled guidance and positioning of conductive and dielectric particles, including biological cells, opening new directions for the accurate and efficient microassembly of biological entities, which is crucial for single cell analysis and other applications in biotechnology...

The rotation of cells is of significant importance in various applications including bioimaging, biophysical analysis and microsurgery. Current methods usually require complicated fabrication processes. Herein, we proposed an induced charged electroosmosis (ICEO) based on a chip manipulation method for rotating cells. Under an AC electric field, symmetric ICEO flow microvortexes formed above the electrode surface can be used to trap and rotate cells. We have discussed the impact of ICEO and dielectrophoresis (DEP) under the experimental conditions...

No abstract text is available yet for this article.

The analysis of cell electrophysiology for pathogenic samples at BSL3 can be problematic. It is virtually impossible to isolate infected from uninfected without a label, for example green fluorescent protein, which can potentially alter the cell electrical properties. Furthermore, the measurement of highly pathogenic organisms often requires equipment dedicated only for use with these organisms due to safety considerations. To address this, we have used dielectrophoresis to study the electrical properties of the human THP-1 cell line and monocyte-derived macrophages before and after infection with non-labelled Mycobacterium tuberculosis...

Single-cell arrays have emerged as a versatile method for executing single-cell manipulations across an array of biological applications. In this paper, an innovative microfluidic platform is unveiled that utilizes optoelectronic tweezers (OETs) to array and sort individual cells at a flow rate of 20 µL min-1 . This platform is also adept at executing dielectrophoresis (DEP)-based, light-guided single-cell retrievals from designated micro-wells. This presents a compelling non-contact method for the rapid and straightforward sorting of cells that are hard to distinguish...

Advances in the Internet of Things (IoT) technology have driven the demand for miniaturized electronic devices, prompting research on small-scale energy-storage systems. Micro-supercapacitors (MSCs) stand out in this regard because of their compact size, high power density, high charge-discharge rate, and extended cycle life. However, their limited energy density impedes commercialization. To resolve this issue, a simple and innovative approach is reported herein for fabricating highly efficient on-chip MSCs integrated with nanoporous metal microwires formed by dielectrophoresis (DEP)-driven gold nanoparticle (AuNP) assembly...

The fillers inside a polymer matrix should typically be self-assembled in both the horizontal and vertical directions to obtain 3-dimentional (3D) percolation pathways, whereby the fields of application can be expanded and the properties of organic-inorganic composite films improved. Conventional dielectrophoresis techniques can typically only drive fillers to self-assemble in only one direction. We have devised a one-step dielectrophoresis-driven approach that effectively induces fillers self-assembly along two orthogonal axes, which results in the formation of 3D interconnected T-shaped iron microstructures (3D-T CIP) inside a polymer matrix...