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Results 451 - 500 of 1437
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Manohar Aswin K - - 2008
Electrochemical impedance spectroscopy (EIS) has been used to determine several electrochemical properties of the anode and cathode of a mediator-less microbial fuel cell (MFC) under different operational conditions. These operational conditions included a system with and without the bacterial catalyst and EIS measurements at the open-circuit potential of the anode ...
Liu W W Department of Mechanical Engineering, University of Victoria, BC, Canada. - - 2008
Experiments using single cells are valuable for revealing individual cell behaviour, which is of interest to many biomedical researchers. In such experiments, various types of devices capable of aligning cells into organized arrays are often used. In this paper, we present a novel Single Cell Micro Array device that makes ...
Borgatti Monica - - 2008
The isolation of rare cells, such as fetal nucleated red blood cells and trophoblasts, from maternal blood for non-invasive prenatal diagnosis is a new field of research exhibiting several difficulties since this strategy requires unresolved basic technological protocols for a successful outcome. However, several achievements in the field of Laboratory-on-a-chip ...
Raptis Leda - - 2008
Electroporation was initially developed for the introduction of DNA into cells which grow in suspension and was performed in a cuvette with two flat electrodes on opposite sides. Different configurations were subsequently developed for the electroporation of adherent cells in situ, while the cells were growing on nonconductive surfaces or ...
Machado David J - - 2008
Single-cell amperometry is a powerful tool for the study of the mechanisms underlying secretion from cells that release electrochemically active substances like catecholamines, histamine, or serotonin. Amperometry has changed our view of the secretory process and the quantal release phenomenon. Today, it is a relatively easy technique to set up ...
Sugiura Tadao - - 2008
Nanomanipulation is a technology to manipulate a small object sized in nanometer to submicron scale. Optical tweezers is one of nanomanipulation techniques, which can investigate pico-newton to femto-newton force exerted on microscopic objects. We have developed a cell palpation system by use of optical tweezers and performed palpation experiments on ...
Al Kindi Adil - - 2008
Experimental and clinical studies have proven the feasibility of cellular cardiomyoplasty in treating the damaged myocardium following ischemic injury. Over the years, this field has exploded with different investigators trying different routes of cell delivery ranging from direct cell injection into the heart to peripheral intravenous delivery utilizing the various ...
Wei Yang - - 2008
The aim of this study is to investigate the effects of extremely low-frequency pulsed electromagnetic field (PEMF) on osteoblast-like cells. PEMF with a magnetic flux density of 1.55 mT at 48 Hz was employed to stimulate the MC3T3-E1 cell and the primary osteoblast cell derived from 2-day-old Sprague Dawley (SD) ...
Raptis Leda - - 2008
Cultured adherent cells can be electroporated in situ, as they grow on a glass slide coated with electrically conductive, optically transparent indium-tin oxide (ITO). Although the introduction of DNA is a common use, the technique of electroporation in situ is valuable for studying many aspects of signal transduction. This is ...
Yang Liju - - 2008
Dielectrophoresis (DEP) has been regarded as a useful tool for manipulating biological cells prior to the detection of cells. Since DEP uses high AC electrical fields, it is important to examine whether these electrical fields in any way damage cells or affect their characteristics in subsequent analytical procedures. In this ...
Prakash Somashekar Bangalore - - 2008
We report a novel technique for assessing cell proliferation that employs integrated capacitance sensors for monitoring the growth of anchorage-dependent living cells. The sensors measure substrate coupling capacitances of cells cultured on-chip in a standard in vitro environment. The biophysical phenomenon underlying the capacitive behavior of cells is the counterionic ...
Feili Dara - - 2008
Organic field effect transistors can be integrated into micromachined polyimide-based neural stimulation electrode arrays in order to build active switching matrices. With this approach, a matrix of N x M electrode contacts requires only N + M interconnects to a stimulator when active switching elements are used instead of N ...
Mathis B J - - 2008
The search for microorganisms that are capable of catalyzing the reduction of an electrode within a fuel cell has primarily been focused on bacteria that operate mesobiotically. Bacteria that function optimally under extreme conditions are beginning to be examined because they may serve as more effective catalysts (higher activity, greater ...
Boettcher Michael - - 2008
We present a simple lab-on-chip device for handling small samples of delicate cells, e.g. stem cells. It uses a combination of sedimentation and dielectrophoresis. The transport of cells is driven by gravitation. Dielectrophoresis uses radio-frequency electric fields for generating particle-selective forces dependent on size and polarisability. Electrodes along the channels ...
Asphahani Fareid F Department of Materials Science & Engineering, University of Washington, Seattle, WA 98195-2120, United - - 2008
Impedance measurements of cell-based sensors are a primary characterization route for detection and analysis of cellular responses to chemical and biological agents in real time. The detection sensitivity and limitation depend on sensor impedance characteristics and thus on cell patterning techniques. This study introduces a cell patterning approach to bind ...
Huh Yun Suk - - 2007
A microfluidic cell lysis chip equipped with a micromixer and SPE unit was developed and used for quantitative analysis of intracellular proteins. This miniaturized sample preparation system can be employed for any purpose where cell disruption is needed to obtain intracellular constituents for the subsequent analysis. This system comprises a ...
Liu Yan-Jun - - 2007
An integrated smart microfluidic device consisting of nickel micropillars, microvalves, and microchannels was developed for specific capture and sorting of cells. A regular hexagonal array of nickel micropillars was integrated on the bottom of a microchannel by standard photolithography, which can generate strong induced magnetic field gradients under an external ...
Calì Corrado - - 2008
Electrical synapses continuously transfer signals bi-directionally from one cell to another, directly or indirectly via intermediate cells. Electrical synapses are common in many brain structures such as the inferior olive, the subcoeruleus nucleus and the neocortex, between neurons and between glial cells. In the cortex, interneurons have been shown to ...
Torchilin Vladimir P - - 2008
Cell-penetrating peptides (CPPs) including TAT peptide (TATp) have been successfully used for intracellular delivery of a broad variety of cargoes including various nanoparticulate pharmaceutical carriers (liposomes, micelles, nanoparticles). Here, we will consider the main results in this area, with a special emphasis on TATp-mediated delivery of liposomes and DNA. We ...
Xu Chun - - 2008
Dental magnetic attachments, usually applied locally to oral cavities, produce stray fields (flux leakage) spreading in adjacent tissues. It has been found that human periodontal ligament (PDL) cells change their geometry and the structure of their cytoskeleton F-actins when the cell cultures are exposed to B-field strengths of B = ...
Moisescu Mihaela G - - 2008
Studying cell behaviour under irradiation with radiofrequency electromagnetic fields (RF-EMF) is often impeded by the difficulty to monitor cell characteristics during irradiation. Here we report the design and the application of a complete device for continuous microscopic observation of cells exposed to modulated EMF similar to mobile phones signals. The ...
Lanthier Martin - - 2008
Shewanella oneidensis MR-1 grew for over 50 days in microbial fuel cells, incompletely oxidizing lactate to acetate with high recovery of the electrons derived from this reaction as electricity. Electricity was produced with lactate or hydrogen and current was comparable to that of electricigens which completely oxidize organic substrates. However, ...
Hunt Thomas P - - 2008
We present an integrated circuit/microfluidic chip that traps and moves individual living biological cells and chemical droplets along programmable paths using dielectrophoresis (DEP). Our chip combines the biocompatibility of microfluidics with the programmability and complexity of integrated circuits (ICs). The chip is capable of simultaneously and independently controlling the location ...
Parkesh Raman - - 2008
NAADP (nicotinic acid adenine dinucleotide phosphate) is a recently discovered second messenger, and as such, we have much yet to learn about its functions in health and disease. A bottleneck in this basic research is due to NAADP, like all second messengers, being charged to prevent it from leaking out ...
Finkelstein Erik I - - 2007
Galvanotaxis, that is, migration induced by DC electric fields, is thought to play a significant role in development and wound healing, however, the mechanisms by which extrinsic electric fields orchestrate intrinsic motility responses are unknown. Using mammalian cell lines (3T3, HeLa, and CHO cells), we tested one prevailing hypothesis, namely, ...
Ateh D D - - 2007
Polypyrrole (PPy) is a conducting polymer that may be electrochemically generated with the incorporation of any anionic species, including net-negatively charged biological molecules such as proteins and polysaccharides. In this article, dermatan and chloride-loaded PPy films were prepared on gold sputter-coated coverslips and various skin derived cells were studied on ...
Cho Young-Ho - - 2007
The paper presents a couple of biofluidic devices, whose functions are inspired from biological cell concentration and deformability monitoring functions. The cell concentration monitoring chip is inspired from RBC control mechanism in kidney, performing cell concentration monitoring functions. The cell deformability chip, inspired from selective RBC destruction mechanism in spleen, ...
Schwenzer Nina F - - 2007
PURPOSE: To evaluate the effects of the static magnetic field and typical imaging sequences of a high-field magnetic resonance scanner (3 Tesla) on the induction of double-strand breaks (DSBs) in two different human cell lines. MATERIALS AND METHODS: Human promyelocytic leukemia cells (HL-60) and human acute myeloid leukemia cells (KG-1a) ...
Ino Kosuke - - 2008
In order to understand the behavior of individual cells, single cell analyses have attracted attention since most cell-based assays provide data with values averaged across a large number of cells. Techniques for the manipulation and analysis of single cells are crucial for understanding the behavior of individual cells. In the ...
Saunders Rachel E - - 2008
A piezoelectric actuated, drop-on-demand inkjet printing system has been used to deliver suspensions of human fibroblast cells from a well-characterized cell line (HT 1080) in order to investigate the behaviour of cells exposed to the mechanical and fluid stresses associated with the printing process. By varying the amplitude and rise ...
Hoshino Akiyoshi - - 2007
Magnetic particles have been used widely in both biotechnological and medical fields, including for immunoassay, enzyme immobilization, drug transport, and immunological diagnosis. Especially particles with bioactive molecules such as antibodies and streptavidin are very useful tools for cell separation. Here we report affinity selection of neutrophils and macrophages from peritoneal ...
Yang Liju - - 2008
In this study, we present a new, simple and rapid impedance method to detect bacterial cells by making use of the impedance properties of bacterial cell suspensions using interdigitated microelectrodes. It was found that bacterial cell suspensions in deionized (DI) water with different cell concentrations could generate different electrical impedance ...
Chung Chiung-Yin - - 2007
INTRODUCTION: Most cardiac arrhythmias are associated with pathology-triggered ion channel remodeling. However, multicellular effects, for example, exaggerated anisotropy and altered cell-to-cell coupling, can also indirectly affect action potential morphology and electrical stability via changed electrotonus. These changes are particularly relevant in structural heart disease, including hypertrophy and infarction. Recent computational ...
Pu Jin - - 2007
The mechanisms by which cancer cells migrate to metastasise are not fully understood. Breast cancers are accompanied by electrical depolarisation of tumour epithelial cells. The electrical changes can be detected on the skin and are used to differentiate malignant from benign breast tumours. Could the electrical signals play a role ...
Jang Ling-Sheng - - 2007
This work presents a microfluidic device to capture physically single cells within microstructures inside a channel and to measure the impedance of a single HeLa cell (human cervical epithelioid carcinoma) using impedance spectroscopy. The device includes a glass substrate with electrodes and a PDMS channel with micro pillars. The commercial ...
Lovelady D C - - 2007
Since 1984, electric cell-substrate impedance sensing (ECIS) has been used to monitor cell behavior in tissue culture and has proven sensitive to cell morphological changes and cell motility. We have taken ECIS measurements on several cultures of noncancerous and cancerous human ovarian surface epithelial cells. By analyzing the noise in ...
Ito Akira - - 2007
Micropatterning of target cells is highly desired for tissue engineering and cell biology. Although recent progress in surface chemistry has enabled the spatial control of cell adhesion onto substrates, conventional methods usually require specialized devices and time-consuming processes to fabricate the substrate. In this study, we demonstrate a simple and ...
Sato Shuichi - - 2007
Applications of dc electric field across parallel plate electrodes filled with an aqueous dispersion of carbon nanotubes produce slowly changing, geometrically regular patterns over the anode surface. The pattern is made visible by nonuniform concentration distributions of black-colored carbon nanotubes. Temporal developments of the pattern can be categorized to the ...
Arumuganathar Sumathy - - 2007
We recently pioneered the ability to directly electrospin living cells from which scaffolds to membranes were derived. This protocol, now widely referred to as 'cell electrospinning', is currently undergoing in-depth investigations where the post-treated cell's global gene expression to its sub-cellular components is being investigated for understanding any effects post-treating. ...
Kim Sang Kyung - - 2007
A microfluidic electroporator operating under a continuous low dc voltage (7 to approximately 15 V) is reported. The proposed electroporation microchip exploits the ionic conductivity of polyelectrolytic gel electrodes to precisely control the electric field that is applied to cells without bubble generation in the microchannel. In this study, pDADMAC ...
Gac Séverine Le - - 2007
We report here the sonoporation of HL60 (human promyelocytic leukemia) suspension cells in a microfluidic confinement using a single laser-induced cavitation bubble. Cavitation bubbles can induce membrane poration of cells located in their close vicinity. Membrane integrity of suspension cells placed in a microfluidic chamber is probed through either the ...
James Conrad D - - 2008
We report here a non-invasive, reversible method for interrogating single cells in a microfluidic flow-through system. Impedance spectroscopy of cells held at a micron-sized pore under negative pressure is demonstrated and used to determine the presence and viability of the captured cell. The cell capture pore is optimized for electrical ...
Irimia Daniel D BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Shriners Hospital for Children, and Harvard Medical School, Boston, MA, USA. - - 2007
Asymmetrical delivery of stimuli to moving cells for perturbing spatially-heterogeneous intracellular signaling is an experimental challenge not adequately met by existing technologies. Here, we report a robust microfluidic platform allowing localized treatment of the front and/or back of moving cells which crawl through narrow channels that they completely occlude. The ...
Nakano Koji - - 2008
The purpose of this study was to investigate the effect of a polymer coating using modified polyvinyl alcohol (PVA-R) on the interaction between liposomes and macrophage cells (J774 cells). The PVA-R-coated liposomes, which were labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocianin perchlorate (DiI) as a fluorescence reagent, were prepared with the conventional hydration method ...
Urdaneta Mario - - 2007
A novel method of modeling multiple frequency dielectrophoresis (MFDEP) is introduced based on the concept of an effective Clausius-Mossotti factor, CM(eff), for a particle that is exposed to electrical fields of different frequencies, coming either from one or multiple pairs of electrodes. This analysis clearly illustrates how adding frequencies adds ...
Mackonis E Claridge - - 2007
Cell survival following exposure to spatially modulated beams, as created by intensity-modulated radiotherapy (IMRT), is investigated. In vitro experiments were performed using malignant melanoma cells (MM576) exposed to a therapeutic megavoltage photon beam. We compared cell survival in modulated fields with cell survival in uniform control fields. Three different spatial ...
Pabst M - - 2007
Electrogenic cells are able to generate electrical signals which can be measured by various invasive electrophysiological methods such as patch-clamp or sharp microelectrode recordings. Growing cells on the surfaces of e.g. metal microelectrodes or field-effect transistors allows the recording of an extracellular component of these signals. For an understanding of ...
Kua Chin Hock - - 2007
This study presents a new cell manipulation method using a moving dielectrophoretic force to transport or fractionate cells along a microfluidic channel. The proposed moving dielectrophoresis (mDEP) is generated by sequentially energizing a single electrode or an array of electrodes to form an electric field that moves cells continuously along ...
Zehbe Rolf - - 2007
The micro structured deposition of vital cells is an important challenge in tissue engineering, biosensor technology, and in all research dealing with cell-cell and cell-substrate contacts. Hence, an inkjet printing technology has been developed to manufacture Au-based micro electrodes by sputter coating inversely printed polyester-foils. These electrodes feature minimal structure ...
Garner Allen L - - 2007
The interaction of nanosecond duration pulsed electric fields (nsPEFs) with biological cells, and the models describing this behavior, depend critically on the electrical properties of the cells being pulsed. Here, we used time domain dielectric spectroscopy to measure the dielectric properties of Jurkat cells, a malignant human T-cell line, before ...
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