scholarly journals A Measurement Setup and Automated Calculation Method to Determine the Charge Injection Capacity of Implantable Microelectrodes

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4152 ◽  
Author(s):  
Ana Cisnal ◽  
Juan-Carlos Fraile ◽  
Javier Pérez-Turiel ◽  
Victor Muñoz-Martinez ◽  
Carsten Müller ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Charge Injection ◽  
Experimental Setup ◽  
Excitable Tissue ◽  
Tissue Resistance ◽  
Voltage Transient ◽  
Transient Measurements ◽  
Functional Electrostimulation

The design of safe stimulation protocols for functional electrostimulation requires knowledge of the “maximum reversible charge injection capacity” of the implantable microelectrodes. One of the main difficulties encountered in characterizing such microelectrodes is the calculation of the access voltage Va. This paper proposes a method to calculate Va that does not require prior knowledge of the overpotential terms and of the electrolyte (or excitable tissue) resistance, which is an advantage for in vivo electrochemical characterization of microelectrodes. To validate this method, we compare the calculated results with those obtained from conventional methods for characterizing three flexible platinum microelectrodes by cyclic voltammetry and voltage transient measurements. This paper presents the experimental setup, the required instrumentation, and the signal processing.

scholarly journals Development of ultrasound echocardiography technique for imaging of the cardiovascular system of small organisms in vivo

2021 ◽  
Vol 2127 (1) ◽  
pp. 012061
Author(s):  
A S Machikhin ◽  
L A Zykova ◽  
A B Burlakov ◽  
S A Titov ◽  
A N Bogachenkov ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Optical Microscope ◽  
Simultaneous Recording ◽  
Video Data ◽  
Optical Data ◽  
Experimental Setup ◽  
High Frequency Ultrasound ◽  
Ultrasonic Signals

Abstract A technique based on a high-frequency ultrasound scanner was developed for imaging and characterization of the cardiovascular system of small organisms in vivo. An optical microscope combined with the ultrasonic unit was used in the experimental setup for simultaneous recording ultrasonic signals and video data. It was shown that combination of optical and ultrasonic data is effective to visualize dynamic processes in a living object. In addition to imaging of the cardiovascular system, video data was processed to estimate the period and phase of the cardiac cycle and to generate a trigger signal for the ultrasonic unit. The proposed approach and developed experimental setup were applied to imaging of the Danio rerio larva. In a result of the processing of the synchronous ultrasonic and optical data, the blood flow in the heart of the larva and the movement of surrounding organs were observed.

Characterization of Electroactive Amino Acids with Fast-Scan Cyclic Voltammetry

2021 ◽  
Author(s):  
Moriah E Weese-Myers ◽  
Ashley E Ross
Keyword(s):  
Amino Acids ◽  
Cyclic Voltammetry ◽  
Electrochemical Technique ◽  
Fast Scan Cyclic Voltammetry ◽  
Design And Optimization ◽  
Peptide Release ◽  
Signaling Peptides ◽  
The Brain

Abstract Small molecules and signaling peptides are extensively involved in controlling basic brain function. While classical neurotransmitters can be detected with a variety of techniques, methods for measurement of rapidly-released neuropeptides remain underdeveloped. Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique often used for subsecond detection of small molecule neurotransmitters, in vivo. A few peptides have been detected with FSCV; however, a detailed analysis of the electrochemical signature of all electroactive amino acids with FSCV has not been fully investigated. Because the mechanisms, locations, and timescales for signaling peptide release in the brain are relatively unexplored, developing sensitive and selective tools capable of quantitating neuropeptide signaling is essential. To bridge this gap, we used FSCV to characterize the electroactive amino acids: cysteine, methionine, histidine, tryptophan, and tyrosine. We show that tyrosine, tryptophan, and histidine are easily oxidized on carbon fiber surfaces with FSCV, while detection of the sulfur-containing amino acids is more difficult. This study provides critical information for electrochemical waveform design and optimization for detection of peptides containing these amino acids.

Application of fast-scan cyclic voltammetry for the in vivo characterization of optically evoked dopamine in the olfactory tubercle of the rat brain

The Analyst ◽  
2016 ◽  
Vol 141 (12) ◽  
pp. 3746-3755 ◽  
Author(s):  
Ken T. Wakabayashi ◽  
Michael J. Bruno ◽  
Caroline E. Bass ◽  
Jinwoo Park
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Fiber ◽  
Rat Brain ◽  
Olfactory Tubercle ◽  
Fast Scan Cyclic Voltammetry ◽  
Carbon Fiber Microelectrodes ◽  
In Vivo Characterization

Dopamine regulation in the rat brain olfactory tubercle was characterized by fast-scan cyclic voltammetry coupled with carbon–fiber microelectrodes and optogenetics.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

Comparison of Immunological and Functional Assays for Measurement of Soluble Fibrin

1995 ◽  
Vol 74 (02) ◽  
pp. 673-679 ◽  
Author(s):  
C E Dempfle ◽  
S A Pfitzner ◽  
M Dollman ◽  
K Huck ◽  
G Stehle ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Low Grade ◽  
Plasma Samples ◽  
Normal Range ◽  
Soluble Fibrin ◽  
Discriminating Power ◽  
Fibrin Monomer ◽  
Cerebral Ischemic

SummaryVarious assays have been developed for quantitation of soluble fibrin or fibrin monomer in clinical plasma samples, since this parameter directly reflects in vivo thrombin action on fibrinogen. Using plasma samples from healthy blood donors, patients with cerebral ischemic insult, patients with septicemia, and patients with venous thrombosis, we compared two immunologic tests using monoclonal antibodies against fibrin-specific neo-epitopes, and two functional tests based on the cofactor activity of soluble fibrin complexes in tPA-induced plasminogen activation. Test A (Enzymun®-Test FM) showed the best discriminating power among normal range and pathological samples. Test B (Fibrinostika® soluble fibrin) clearly separated normal range from pathological samples, but failed to discriminate among samples from patients with low grade coagulation activation in septicemia, and massive activation in venous thrombosis. Functional test C (Fibrin monomer test Behring) displayed good discriminating power between normal and pathological range samples, and correlated with test A (r = 0.61), whereas assay D (Coa-Set® Fibrin monomer) showed little discriminating power at values below 10 μg/ml and little correlation with other assays. Standardization of assays will require further characterization of analytes detected.

Insulinomimetic properties of trace elements and characterization of their in vivo mode of action

Diabetes ◽  
1990 ◽  
Vol 39 (10) ◽  
pp. 1243-1250 ◽  
Author(s):  
L. Rossetti ◽  
A. Giaccari ◽  
E. Klein-Robbenhaar ◽  
L. R. Vogel
Keyword(s):  
Trace Elements ◽  
Mode Of Action

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

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