scholarly journals Multichannel cell detection in microcompartments by means of true parallel measurements using the Solartron S-1260

2020 ◽  
Vol 11 (1) ◽  
pp. 49-56
Author(s):  
T.A. Nguyen ◽  
D. Echtermeyer ◽  
A. Barthel ◽  
G. Urban ◽  
U. Pliquett
Keyword(s):  
Electrode Array ◽  
Cell Behavior ◽  
Cell Detection ◽  
Multielectrode Arrays ◽  
Behavior Monitoring ◽  
Common Electrode ◽  
The Common ◽  
Electrode Systems ◽  
Generator Output ◽  
Simultaneous Assessment

AbstractDesigning proper frontend electronics is critical in the development of highly sophisticated electrode systems. Multielectrode arrays for measuring electrical signals or impedance require multichannel readout systems. Even more challenging is the differential or ratiometric configuration with simultaneous assessment of measurement and reference channels. In this work, an eight-channel frontend was developed for contacting a 2×8 electrode array (8 measurement and 8 reference electrodes) with a large common electrode to the impedance gain-phase analyzer Solartron 1260 (S-1260). Using the three independent and truly parallel monitor channels of the S-1260, impedance of trapped cells and reference material was measured at the same time, thereby considerably increasing the performance of the device. The frontend electronics buffers the generator output and applies a potentiostatic signal to the common electrode of the chip. The applied voltage is monitored using the current monitor of the S-1260 via voltage/current conversion. The frontend monitors the current through the electrodes and converts it to a voltage fed into the voltage monitors of the S-1260. For assessment of the 8 electrode pairs featured by the chip, a relay-based multiplexer was implemented. Extensive characterization and calibration of the frontend were carried out in a frequency range between 100 Hz and 1 MHz. Investigating the influence of the multiplexer and the frontend electronics, direct measurement with and without frontend was compared. Although differences were evident, they have been negligible below one per cent. The significance of measurement using the complex S-1260-frontend-electrode was tested using Kohlrausch's law. The impedance of an electrolytic dilution series was measured and compared to the theoretical values. The coincidence of measured values and theoretical prediction serves as an indicator for electrode sensitivity to cell behavior. Monitoring of cell behavior on the microelectrode surface will be shown as an example.

scholarly journals EEG Assessment in Patients With Disorders of Consciousness: Aims, Advantages, Limits, and Pitfalls

2021 ◽  
Vol 12 ◽  
Author(s):  
Davide Rossi Sebastiano ◽  
Giulia Varotto ◽  
Davide Sattin ◽  
Silvana Franceschetti
Keyword(s):  
Electrode Array ◽  
Analytical Techniques ◽  
Clinical Use ◽  
Eeg Signal ◽  
Review Of Literature ◽  
Future Developments ◽  
Complex Patient ◽  
Common Electrode ◽  
Signal Processing Methods ◽  
Eeg Signal Processing

This study presents a brief review of literature exploring simple EEG-polygraphic examinations and procedures that can be carried out at a patient's bedside. These include EEG with a common electrode array and sleep evaluation. The review briefly discusses more complex analytical techniques, such as the application of advanced EEG signal processing methods developed by our research group, to define what type of consistent markers are suitable for clinical use or to better understand complex patient conditions. These advanced analytical techniques aim to detect relevant EEG-based markers that could be useful in evaluating patients and predicting outcomes. These data could contribute to future developments in research.

scholarly journals A Surgical Navigation System for Guiding Exact Cochleostomy Using Auditory Feedback: A Clinical Feasibility Study

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Byunghyun Cho ◽  
Nozomu Matsumoto ◽  
Shizuo Komune ◽  
Makoto Hashizume
Keyword(s):  
Feasibility Study ◽  
Navigation System ◽  
Auditory Feedback ◽  
Surgical Navigation ◽  
Complex Structure ◽  
Electrode Array ◽  
Scala Tympani ◽  
Correct Placement ◽  
Surgical Navigation System ◽  
The Common

In cochlear implantation (CI), the insertion of the electrode array into the appropriate compartment of the cochlea, the scala tympani, is important for an optimal hearing outcome. The current surgical technique for CI depends primarily on the surgeon’s skills and experience level to achieve the correct placement of the electrode array, and the surgeon needs to confirm that the exact placement is achieved prior to completing the procedure. Thus, a surgical navigation system can help the surgeon to access the scala tympani without injuring important organs in the complex structure of the temporal bone. However, the use of a surgical microscope has restricted the effectiveness of the surgical navigation because it has been difficult to deliver the navigational information to the surgeon from outside of the surgeon’s visual attention. We herein present a clinical feasibility study of an auditory feedback function developed as a computer-surgeon interface that can guide the surgeon to the preset cochleostomy location. As a result, the surgeon could confirm that the drilling point was correct, while keeping his or her eyes focused on the microscope. The proposed interface reduced the common frustration that surgeons experience when using surgical navigation during otologic surgeries.

Cell Imaging via Multi-Electrode Array Using Microfluidic Chip

2019 ◽  
Vol 9 (6) ◽  
pp. 1267-1271
Author(s):  
Dayong Fan ◽  
Jiafeng Yao
Keyword(s):  
Electrical Impedance Tomography ◽  
Microfluidic Chip ◽  
Electrical Impedance ◽  
Material Selection ◽  
Electrode Array ◽  
Cell Number ◽  
Structure Design ◽  
Cell Detection ◽  
Impedance Tomography ◽  
Multi Electrode Array

As a new medical detection method, electrical impedance tomography has been used in biology and medicine in recent years due to its advantages such as safety, non-invasiveness and radiation-free. In this paper, we designed a multi-electrode array microfluidic chip for the cell detection with electrical impedance tomography. The microfluidic chip structure design, material selection and processing technology are emphatically described. Finally, the feasibility of microfluidic chip for the cell with electrical impedance tomography is verified by simulations with different cell number and different electrodes excitation pattern.

scholarly journals Electrocardiogram Artifacts Caused by Deep Brain Stimulation

2004 ◽  
Vol 31 (3) ◽  
pp. 343-346 ◽  
Author(s):  
Constantine Constantoyannis ◽  
Brett Heilbron
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Electrode Position ◽  
The Status ◽  
Common Electrode ◽  
The Common ◽  
Bipolar Patients ◽  
Ecg Artifacts ◽  
Ecg Interpretation ◽  
Deep Brain

Background:Deep brain stimulation (DBS) is increasingly used to treat a variety of neurological conditions (e.g. movement disorders and chronic pain). This prospective study was designed to detect electrocardiogram (ECG) artifacts induced by deep brain stimulation and to investigate which factors (patient disease, electrode position within the brain or type of stimulation) produced these artifacts.Methods:Twelve patients (four women, eight men) with deep brain stimulators were enrolled in the study. Patients were selected to represent the common indications for DBS (Parkinson's disease, tremor, dystonia), the common electrode locations (pallidum, thalamus, subthalamic nucleus) and the two types of stimulation (monopolar, bipolar). Patients had one ECG with the DBS turned 'on'and another with the DBS turned 'off'. The ECGs were then randomized and read by a cardiologist blinded to the status of the patient and DBS and artifacts were noted to be either present or absent.Results:The six patients using monopolar stimulation all had artifacts on their electrocardiograms. These artifacts were severe enough to interfere with ECG interpretation. There were no artifacts detected in the six patients using bipolar stimulation. Electrode location and patient disease appeared to have no effect on ECG artifact.Conclusion:Deep brain stimulation can cause ECG artifacts when monopolar settings are used. These artifacts are not present with bipolar settings or when the DBS is turned 'off'. Knowledge of these potential ECG artifacts and how to avoid them is essential to facilitate accurate ECG interpretation.

scholarly journals Implication of integrin α5β1 in human breast carcinoma apoptosis and drug resistance

2011 ◽  
Vol 57 (1) ◽  
pp. 77-84 ◽  
Author(s):  
G.E. Morozevich ◽  
N.I. Kozlova ◽  
N.A. Ushakova ◽  
M.E. Preobrazhenskaya ◽  
A.E. Berman
Keyword(s):  
Significant Inhibition ◽  
Cell Behavior ◽  
Signal Pathways ◽  
Human Breast ◽  
Integrin Α5β1 ◽  
Increased Sensitivity ◽  
The Common ◽  
Common Signal ◽  
Α2β1 Integrin ◽  
Mcf 7

Doxorubicin-resistant MCF-7Dox line, which is a derivative of the drug-sensitive MCF-7 human breast carcinima line, differs from the latter by a strongly reduced expression of the α2β1 integrin and a highly increased expression of the α5β1 receptor. Silencing of this integrin in the MCF-7Dox cells by transfection with α5-specific siRNA markedly stimulated anoikis and increased sensitivity of the cells to doxorubicin. α5β1 silencing also leads to significant inhibition of the activity of kinases Akt and Erk2 in MCF-7Dox cells. Our results suggest that integrins α5β1-induced signals, controlling distinct aspects of cell behavior, are conducted through the common signal pathways.

Stretchable Bioelectrodes

2010 ◽  
Vol 1271 ◽  
Author(s):  
Pinghung Wei ◽  
B. Ziaie
Keyword(s):  
Room Temperature ◽  
Mechanical Strain ◽  
Electrode Array ◽  
Cell Behavior ◽  
Stretchable Electrode

AbstractIn this paper, we present a stretchable electrode array for studying cell behavior subjected to mechanical strain. The electrode array consists of four gold nail-head pins (250μm tip diameter and 1.75mm spacing) or tungsten microwires (25.4μm in diameter) inserted into a polydimethylsiloxane (PDMS) platform (25.4×25.4mm2). Fusible indium alloy (liquid at room temperature) filled microchannels were used to connect the electrodes to the outside, thus providing the required stretchability. The electrodes were able to withstand strains of up to 40%. Repeated strain tests of several hundred cycles did not reveal any failure, illustrating the robustness of the platform. Mice cardiomyocytes and chick neurons were successfully cultured onto the platform.

scholarly journals Multi-Electrode Array with a Planar Surface for Cell Patterning by Microprinting

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5379 ◽  
Author(s):  
Jan Slavík ◽  
Josef Skopalík ◽  
Ivo Provazník ◽  
Jaromír Hubálek
Keyword(s):  
Electrode Array ◽  
Adhesive Layer ◽  
Microfluidic Channels ◽  
Multielectrode Arrays ◽  
Insulation Layer ◽  
Planar Surface ◽  
Non Invasive ◽  
Electrophysiological Measurements ◽  
A Cell ◽  
Poly Ethylene

Multielectrode arrays (MEAs) are devices for non-invasive electrophysiological measurements of cell populations. This paper describes a novel fabrication method of MEAs with a fully planar surface. The surface of the insulation layer and the surface of the electrodes were on one plane; we named this device the planar MEA (pMEA). The main advantage of the pMEA is that it allows uniform contact between the pMEA surface and a substrate for positioning of microfluidic channels or microprinting of a cell adhesive layer. The fabrication of the pMEA is based on a low adhesive Au sacrificial peel-off layer. In divergence from conventional MEAs with recessed electrodes, the electrodes of the pMEA lead across the sloped edge of the insulation layer. To make this, the profile of the edge of the insulation layer was measured and the impedance of the planar electrodes was characterized. The impedance of the pMEA was comparable with the impedance of conventional MEA electrodes. The pMEA was tested for patterning HL-1 cells with a combination of imprinting fibronectin and coating by antifouling poly (l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG). The HL-1 cells remained patterned even at full confluency and presented spontaneous and synchronous beating activity.

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