Hybrid Cell Adhesive Material for Instant Dielectrophoretic Cell Trapping and Long-Term Cell Function Assessment (original) (raw)
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Lab on a Chip, 2014
In this manuscript, we demonstrate the rapid formation of three-dimensional (3D) embryonic stem cell (ESC) aggregates with controllable sizes and shapes in hydrogels using dielectrophoresis (DEP). The ESCs encapsulated within a methacrylated gelatin (GelMA) prepolymer were introduced into a DEP device and, upon applying an electric field and crosslinking of the GelMA hydrogel, formed 3D ESC aggregates. Embryoid bodies (EBs) fabricated using this method showed high cellular viability and pluripotency. The proposed technique enables production of EBs on a large scale and in a high-throughput manner for potential cell therapy and tissue regeneration applications.
Spatial manipulation of cells and organelles using single electrode dielectrophoresis
BioTechniques, 2012
The selection, isolation, and accurate positioning of single cells in three dimensions are increasingly desirable in many areas of cell biology and tissue engineering. We describe the application of a simple and low cost dielectrophoretic device for picking out and relocating single target cells. The device consists of a single metal electrode and an AC signal generator. It does not require microfabrication technologies or sophisticated electronics. The dielectrophoretic manipulator also discriminates between live and dead cells and is capable of redistributing intracellular organelles.
Exercising Spatiotemporal Control of Cell Attachment with Optically Transparent Microelectrodes
Langmuir, 2008
This paper describes a novel approach of controlling cell-surface interactions through an electrochemical "switching" of biointerfacial properties of optically transparent microelectrodes. The indium tin oxide (ITO) microelectrodes, fabricated on glass substrates, were modified with poly(ethylene glycol) (PEG) silane to make glass and ITO regions resistant to protein and cell adhesion. Cyclic voltammetry, with potassium ferricyanide serving as a redox reporter molecule, was used to monitor electron transfer across the electrolyte-ITO interface. PEG silane modification of ITO correlated with diminished electron transfer, judged by the disappearance of ferricyanide redox activity. Importantly, application of reductive potential (−1.4 V vs Ag/AgCl reference) corresponded with reappearance of typical ferricyanide redox peaks, thus pointing to desorption of an insulating PEG silane layer. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) characterization of the silanized ITO surfaces after electrical stimulation indicated complete removal of the silane layer. Significantly, electrical stimulation allowed to "switch" chosen electrodes from nonfouling to protein-adhesive while leaving other ITO and glass regions protected by a nonfouling PEG silane layer. The spatial and temporal control of biointerfacial properties afforded by our approach was utilized to micropattern proteins and cells and to construct micropatterned co-cultures. In the future, control of the biointerfacial properties afforded by this novel approach may allow the organization of multiple cell types into precise geometric configurations in order to create better in vitro mimics of cellular complexity of the native tissues.
Biomedical Microdevices, 2008
The manipulation of biological cells is essential to many biomedical applications. Insulator-based dielectrophoresis (iDEP) trapping consists of insulating structures which squeeze the electric field in a conductive solution to create a non-uniform electric field. The iDEP trapping microchip with the open-top microstructures was designed and fabricated in this work. For retaining the merit of microfabrication, the microelectrodes were deposited on the substrate to reduce the voltage required, due to the shortened spacing between them. The dielectrophoretic responses of both live and dead HeLa cells under different frequencies (100 Hz, 1 kHz and 1 MHz) have been investigated herein. The live cells exhibited negative dielectrophoresis at low frequencies of 100 Hz and 1 kHz, but a positive dielectrophoretic response with the frequency at 1 MHz. As for dead cells, positive dielectrophoretic responses were shown at all the frequencies applied. Therefore, selective trapping of dead HeLa cells from live cells was achieved experimentally at the frequency of 1 kHz. The open-top microstructures are suitable for trapping cells or biological samples, and easily proceeding to further treatment for cells, such as culturing or contact detection. The intensity of the emitted light during fluorescent detection will not suffer interference by a cover, as it does not exist herein.
Label-free Isolation and Enrichment of Cells Through Contactless Dielectrophoresis
Journal of Visualized Experiments, 2013
Dielectrophoresis (DEP) is the phenomenon by which polarized particles in a non-uniform electric field undergo translational motion, and can be used to direct the motion of microparticles in a surface marker-independent manner. Traditionally, DEP devices include planar metallic electrodes patterned in the sample channel. This approach can be expensive and requires a specialized cleanroom environment. Recently, a contact-free approach called contactless dielectrophoresis (cDEP) has been developed. This method utilizes the classic principle of DEP while avoiding direct contact between electrodes and sample by patterning fluidic electrodes and a sample channel from a single polydimethylsiloxane (PDMS) substrate, and has application as a rapid microfluidic strategy designed to sort and enrich microparticles. Unique to this method is that the electric field is generated via fluidic electrode channels containing a highly conductive fluid, which are separated from the sample channel by a thin insulating barrier. Because metal electrodes do not directly contact the sample, electrolysis, electrode delamination, and sample contamination are avoided. Additionally, this enables an inexpensive and simple fabrication process.
Electro-mechanical manipulation of mammalian cells in suspension
2011 - 14th International Symposium on Electrets, 2011
Low-frequency storage modulus, G'(ω), given by Eq. (11). † All values are mean ± SD (CHO: N = 5, U937: N = 10). APPENDIX II. Gene delivery by electroporation after dielectrophoretic positioning of cells in a non-uniform electric field
Biotechnology and Bioengineering, 2003
In this study we describe an original, efficient, and innovative printed circuit board (PCB) device able to generate dielectrophoresis-based, software-controlled cages that can be moved to any place inside a microchamber. Depending on their dielectrophoretic properties, eukaryotic cells can be “entrapped” in cages and moved under software control. The main conclusion gathered from the experimental data reported is that the PCB device based on dielectrophoresis permits levitation and movement of different tumor cells at different dielectrophoresis conditions. The results presented herein are therefore the basis for experiments aimed at forced interactions or separation of eukaryotic cells using “lab-on-a-chip.” In fact, because many cages can be controlled at the same time, and two or more cages can be forced to share the same or a different location, it is possible, in principle, either to bring in contact cells of a differing histotype or to separate them. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 474–479, 2003.
Scientific reports, 2018
Dielectrophoresis using multi-electrode arrays allows a non-invasive interface with biological cells for long-term monitoring of electrophysiological parameters as well as a label-free and non-destructive technique for neuronal cell manipulation. However, experiments for neuronal cell manipulation utilizing dielectrophoresis have been constrained because dielectrophoresis devices generally function outside of the controlled environment (i.e. incubator) during the cell manipulation process, which is problematic because neurons are highly susceptible to the properties of the physiochemical environment. Furthermore, the conventional multi-electrode arrays designed to generate dielectrophoretic force are often fabricated with non-transparent materials that confound live-cell imaging. Here we present an advanced single-neuronal cell culture and monitoring platform using a fully transparent microfluidic dielectrophoresis device for the unabated monitoring of neuronal cell development and ...
Methods of Micropatterning and Manipulation of Cells for Biomedical Applications
Micromachines
Micropatterning and manipulation of mammalian and bacterial cells are important in biomedical studies to perform in vitro assays and to evaluate biochemical processes accurately, establishing the basis for implementing biomedical microelectromechanical systems (bioMEMS), point-of-care (POC) devices, or organs-on-chips (OOC), which impact on neurological, oncological, dermatologic, or tissue engineering issues as part of personalized medicine. Cell patterning represents a crucial step in fundamental and applied biological studies in vitro, hence today there are a myriad of materials and techniques that allow one to immobilize and manipulate cells, imitating the 3D in vivo milieu. This review focuses on current physical cell patterning, plus chemical and a combination of them both that utilizes different materials and cutting-edge micro-nanofabrication methodologies.
Selective trapping of single mammalian breast cancer cells by insulator-based dielectrophoresis
The trapping or immobilization of individual cells at specific locations in microfluidic platforms is essential for single cell studies, especially those requiring cell stimulation and downstream analysis of cellular content. Selectivity for individual cell types is required when mixtures of cells are analyzed in heterogeneous and complex matrices, such as the selection of metastatic cells within blood samples. Here, we demonstrate a microfluidic device based on direct current (DC) insulator-based dielectrophoresis (iDEP) for selective trapping of single MCF-7 breast cancer cells from mixtures with both mammalian peripheral blood mononuclear cells (PBMC) as well MDA-MB-231 as a second breast cancer cell type. The microfluidic device has a teardrop iDEP design optimized for the selective capture of single cells based on their differential DEP behavior under DC conditions. Numerical simulations adapted to experimental device geometries and buffer conditions predicted the trapping condition in which the dielectrophoretic force overcomes electrokinetic forces for MCF-7 cells, whereas PBMCs were not trapped.