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Electrophysiology
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
In electrochemistry, the interrelationship between the electric and ionic activities are commonly considered for electrode design. Using the Nernst Equation (3.10), the electric potential (E) will be present between the ions on either side of the cell membrane (Bronzino, 2000):
EM behavior when the wavelength is large compared to the object size
Published in James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney, Basic Introduction to Bioelectromagnetics, 2018
James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney
Electrodes interact with the basic elements of the nervous system, the neurons that combine to create nerves, which transmit impulses throughout the body. A protective fatty coating called myelin insulates the nerve fibers, so that several fibers can run side by side in a bundle without interfering with each other. In this respect, nerves work much like transmission lines and are sometimes modeled this way electrically. The nerve cell uses a combination of electricity and electrochemistry. The synaptic terminals at the ends of the nerve hold neurotransmitter chemicals in membranous sacs. When the electrical signal reaches the end of the nerve, the neurotransmitters are released. The chemical neurotransmitters spread across the gap between the neurons, and at the next neuron stimulate the production of an electrical charge, which carries the nerve impulse forward into the next neuron. Thus, along the length of a neuron, the signal is purely electrical, and at the junctions, it is electrochemical. Electricity can be used to stimulate the neuron either along its length or at a junction. Receiving electrical signals must generally be done along the length of a neuron.
Technological Evolution of Wireless Neurochemical Sensing with Fast-Scan Cyclic Voltammetry
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
Dan P. Covey, Kevin E. Bennet, Charles D. Blaha, Pedram Mohseni, Kendall H. Lee, Paul A. Garris
Although new optical methods are being developed [10], neurotransmitters have traditionally been measured by using microdialysis and voltammetry. In microdialysis, an analyte is physically removed from the brain extracellular fluid for an ex vivo determination [11]. Sophisticated analytical tools such as capillary electrophoresis, laser-induced fluorescence, and mass spectrometry have been coupled to this sampling technique, and these provide it with exquisite sensitivity and selectivity. However, large probe size (~200 μm) and slow sampling rates (minutes) are a limiting factor. Because neurotransmitters are directly monitored at an implanted microsensor using electrochemistry, voltammetry exhibits superior temporal and spatial resolution [12]. Previously criticized aspects of voltammetry are poor selectivity due to the plethora of easily oxidized species in the brain extracellular fluid, and poor sensitivity. As described in Section 7.3, recent advances in electrochemistry for neurochemical sensing have addressed these criticisms, and now this approach has become the technique of choice for many in vivo monitoring applications.
Applications of trimetallic nanomaterials as Non-Enzymatic glucose sensors
Published in Drug Development and Industrial Pharmacy, 2023
Israr U. Hassan, Gowhar A. Naikoo, Fareeha Arshad, Fatima Ba Omar, Alaa A. A. Aljabali, Vijay Mishra, Yachana Mishra, Mohamed EL-Tanani, Nitin B. Charbe, Sai Raghuveer Chava, Ángel Serrano-Aroca, Murtaza M. Tambuwala
Because of their extraordinary properties, Au, Pt, and Pd are commonly used in the field of electrochemistry, especially in the development of biosensors for the detection of various target molecules. In an exciting study by Han et al. researchers developed trimetallic Pt-Au-Pd nanoparticles for the electrochemical sensing of glucose molecules [15]. The team used β-lactoglobulin (BLG) as a dispersant to enhance their extraordinary properties, Au, Pt, and Pd are commonly used in the field of electrochemistry, especially in the development of biosensors for the detection of various target molecules. In an exciting study by Han et al. researchers developed trimetallic Pt-Au-Pd nanoparticles for electrochemical sensing of glucose molecules. The team used β-lactoglobulin (BLG) as a dispersant to enhance the biocompatibility of the electrochemical sensor developed.
Phase I and phase II metabolism simulation of antitumor-active 2-hydroxyacridinone with electrochemistry coupled on-line with mass spectrometry
Published in Xenobiotica, 2019
Agnieszka Potęga, Dorota Garwolińska, Anna M. Nowicka, Michał Fau, Agata Kot-Wasik, Zofia Mazerska
In this work, the ability of EC/MS to expedite the generation and identification of the main phase I metabolites of 2-OH-AC will be discussed. The formation of the reactive 2-OH-AC intermediate metabolite and the possibility to simulate its covalent binding to biomolecule (i.e. glutathione (GSH) and/or N-acetylcysteine (NAC) as biomarkers of metabolic activity; phase II metabolism) are also taken into account. Furthermore, to show the capability of electrochemistry to simulate certain P450-mediated reactions, the results obtained by EC were also compared with those gained after controlled-potential electrolysis (CPE) and conventional in vitro studies by conducting incubations of 2-OH-AC with human and rat liver microsomes (HLMs and RLMs, respectively). The products of electrolysis and enzymatic transformations of 2-OH-AC were analyzed by reversed-phase liquid chromatography (LC) with UV-Vis detection and/or diode array detection and monitored by MS. The relation between the products generated electrochemically and enzymatically for the model compound 2-OH-AC can provide a clue to the nature of their metabolic pathway initiation (Volk et al., 1992). It opens up further perspectives directed to the search for more effective and less toxic antitumor drugs among acridinone derivatives. It is significant because it improves the risk evaluation for potential drugs in the optimal chemotherapy schedules designed for individual patients.
Biodistribution and targeting properties of iron oxide nanoparticles for treatments of cancer and iron anemia disease
Published in Nanotoxicology, 2019
To synthesize IONP, various chemical synthesis have been suggested, which involve: (i) co-precipitation by mixing ferrous and ferric salts in an aqueous medium (Martínez-Mera et al. 2007), (ii) electrochemistry where an electric current is applied between an anode and a cathode introduced in an electrolyte, the anode oxidizes metal ions of the electrolyte that are further reduced to metal by the cathode with the help of stabilizers (Khan and Petrikowski 2000; Ramimoghadam, Bagheri, and Hamid 2014), (iii) flow injection syntheses by mixing reagents under laminar flow regime in a capillary reactor (Salazar-Alvarez, Muhammed, and Zagorodni 2006), (iv) hydrothermal reactions in which mixed metal hydroxides can be autoclaved to produce nanoparticle powders (Wan et al. 2005), (v) laser pyrolysis where a laser heats a mixture of iron precursors and a flowing mixture of gas (Veintemillas-Verdaguer 1998), (vi) high temperature reaction of polyol with an iron source (Cai and Wan 2007), (vii) sol-gel methods in which precursors undergo hydroxylation and condensation to yield nanometric particles (sol), followed by condensation and polymerization to produce a three-dimensional metal oxide network (wet gel), ending by a heating process that results in a crystallized structure (Albornoz and Jacobo 2006), (viii) sonolysis or thermolysis involving the decomposition or collapse of organometallic precursors such as ferrous salts (Osuna et al. 1996), (ix) spray pyrolysis in which solutions of ferric salts and a reducing agent in organic solvent is sprayed in reactors leading to the condensation of the aerosol solute and solvent evaporation (Pecharromán 1994).