scholarly journals Amperometric Biosensors for L-Arginine Determination Based on L-Arginine Oxidase and Peroxidase-Like Nanozymes

2021 ◽  
Vol 11 (15) ◽  
pp. 7024
Author(s):  
Nataliya Stasyuk ◽  
Galina Gayda ◽  
Olha Demkiv ◽  
Lyubomyr Darmohray ◽  
Mykhailo Gonchar ◽  
...  
Keyword(s):  
Pharmaceutical Preparation ◽  
Enzymatic Reaction ◽  
High Sensitivity ◽  
The Novel ◽  
Limited Data ◽  
Amperometric Biosensors ◽  
Graphite Electrodes ◽  
Sensitivity And Selectivity ◽  
The Cost

There are limited data on amperometric biosensors (ABSs) for L-arginine (Arg) determination based on oxidases that produce hydrogen peroxide (H2O2) as a byproduct of enzymatic reaction, and artificial peroxidases (POs) for decomposition of H2O2. The most frequently proposed Arg-sensitive oxidase-based ABSs contain at least two enzymes in the bioselective layer; this complicates the procedure and increases the cost of analysis. Therefore, the construction of a one-enzyme ABS for Arg analysis is a practical problem. In the current work, fabrication, and characterization of three ABS types for the direct measurement of Arg were proposed. L-arginine oxidase (ArgO) isolated from the mushroom Amanita phalloides was co-immobilized with PO-like nanozymes (NZs) on the surface of graphite electrodes. As PO mimetics, chemically synthesized NZs of CeCu (nCeCU) and NiPtPd (nNiPtPd), as well as green-synthesized hexacyanoferrate of copper (gCuHCF), were used. The novel ABSs exhibited high sensitivity and selectivity to Arg, broad linear ranges and good storage stabilities. Two ABSs were tested on real samples of products containing Arg, including the pharmaceutical preparation “Tivortine”, juices, and wine. A high correlation (R = 0.995) was demonstrated between the results of testing “Tivortine” and juice using nCeCU/GE and nNiPtPd/GE. It is worth mentioning that only a slight difference (less than 1%) was observed for “Tivortin” between the experimentally determined content of Arg and its value declared by the producer. The proposed ArgO-NZ-based ABSs may be promising for Arg analysis in different branches of science, medicine, and industry.

scholarly journals Synthesis and Characterization of the Perthiatriarylmethyl Radical and Its Dendritic Derivatives with High Sensitivity and Selectivity to Superoxide Radical

2018 ◽  
Vol 24 (27) ◽  
pp. 6865-6865 ◽  
Author(s):  
Xiaoli Tan ◽  
Shanqing Tao ◽  
Wenbo Liu ◽  
Antal Rockenbauer ◽  
Frederick A. Villamena ◽  
...  
Keyword(s):  
Superoxide Radical ◽  
High Sensitivity ◽  
Synthesis And Characterization ◽  
Sensitivity And Selectivity

scholarly journals Chromatographic Methods for the Determination of Aminexil, Pyridoxine, and Niacinamide in a Novel Cosmetic Hair Preparation

2020 ◽  
Vol 103 (4) ◽  
pp. 1167-1172
Author(s):  
Mamdouh R Rezk ◽  
Hebatallah M Essam ◽  
Enas A Amer ◽  
Dina M S Youssif
Keyword(s):  
High Performance ◽  
High Sensitivity ◽  
Ammonia Solution ◽  
Hplc Method ◽  
The Novel ◽  
Chromatographic Methods ◽  
Ich Guidelines ◽  
Sensitivity And Selectivity ◽  
Keratin Fibers

Abstract Background Aminexil, a new compound patented by L’Oreal, has a stimulating effect on human keratin fibers. Pyridoxine HCl and niacinamide are added to boost the hair tonic effect of aminexil. Objective Two novel chromatographic methods were developed for the determination of aminexil (AX), niacinamide (NA) and pyridoxine HCl (PD) in the novel hair tonic preparation. Methods The developed methods were high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) with densitometric determination. Different experimental parameters were investigated and optimized to achieve complete baseline separation and well resolved peaks. The RP-HPLC separation was achieved using a Thermoscientific BDS hypersil C18 (250 × 4.6 mm, 5 µm) column using 0.005 M hexane sulfonic acid: methanol (80: 20, v/v) as a mobile phase. For the TLC method, the three analytes were partitioned between propanol: toluene: ammonia solution (40:60:2, v/v/v) and fluorescent silica plates. The two methods were validated in compliance with International Conference on Harmonization (ICH) guidelines. The obtained data were statistically analyzed to confirm the existing results. The developed methods were successfully applied for determination of the studied drugs in pure forms and in the cosmetic preparation. Results For the HPLC method, the RSDs of AX, NA and PD were 0.70, 0.88 and 1.17 respectively. For the TLC method, the RSDs of AX, NA and PD were 1.06, 1.37 and 0.73 respectively. Conclusions The proposed chromatographic methods showed high sensitivity and selectivity for the three compounds under analysis in the laboratory prepared mixture and in the hair tonic preparation. Highlights Aminexil, Pyridoxine, Niacinamide, HPLC. The present work offers two reproducible, accurate, validated, time and cost saving alternatives for the quantitative and qualitative determination of medicated hair preparation.

Molecular Motor and Electrokinetic Contributions to Outer Hair Cell Electromotility

1998 ◽  
Vol 79 (1) ◽  
pp. 471-473 ◽  
Author(s):  
Rocco A. Jerry ◽  
Ashim Dutta
Keyword(s):  
Hair Cell ◽  
Molecular Motors ◽  
Outer Hair Cell ◽  
Motor Behavior ◽  
Molecular Motor ◽  
High Sensitivity ◽  
Length Change ◽  
The Novel ◽  
Sensitivity And Selectivity ◽  
A New Technique

Jerry, Rocco A. and Ashim Dutta. Molecular motor and electrokinetic contributions to outer hair cell electromotility. J. Neurophysiol. 79: 471–473, 1998. The outer hair cell of the inner ear is believed to be responsible for the high sensitivity and selectivity of mammalian hearing. Molecular motors are generally believed to cause the electrically-driven length change (electromotility) of the outer hair cell. It has been suggested that electrokinetic effects might also play a significant role in electromotility, along with the molecular motors. This paper describes a new technique that can be used to experimentally determine the percentage of the electromotile response that is caused by electrokinetic effects. The technique is based on the novel idea that molecular motor activity cannot in itself generate a net force on the cell, but that electrokinetic effects can. Our method is the first that can separate molecular motor behavior from electrokinetic behavior, during experiments on the outer hair cell.

Synthesis and characterization of combinatorial libraries of semiconductor gas sensors.

2003 ◽  
Vol 804 ◽  
Author(s):  
M. A. Aronova ◽  
K. S. Chang ◽  
I. Takeuchi ◽  
H. Jabs ◽  
D. Westerheim ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Pulsed Laser ◽  
Combinatorial Libraries ◽  
High Sensitivity ◽  
Pulsed Laser Ablation ◽  
Electronic Noses ◽  
Sensitivity And Selectivity ◽  
Semiconductor Gas Sensors ◽  
Array Geometry

ABSTRACTWe have fabricated thin-film combinatorial gas sensor libraries based on doped semiconducting SnO2 thin films. The utility of combinatorial libraries is two-fold: one is to search and optimize the compositions for high sensitivity and selectivity of gases, and the other is to make use of the natural array geometry of the libraries with different sensor elements for electronic noses. Combinatorial pulsed-laser ablation was used to deposit compositionally varying arrays of sensor elements onto a pre-patterned device electrode configuration. Using a multiplexing electronics, we have demonstrated detection of chloroform, formaldehyde, and benzene gases at concentrations down to 12.5 ppm through pattern recognition of signals from the arrays of sensors.

CdSe Quantum Dots Decorated by 3-Aminobenzeneboronic Acid as Fluorescence Probe for Glucose

2011 ◽  
Vol 306-307 ◽  
pp. 1338-1341
Author(s):  
Shao Wei Wang ◽  
Xia Ona Zhang ◽  
Jing Hua Yu
Keyword(s):  
Quantum Dots ◽  
Fluorescence Probe ◽  
High Sensitivity ◽  
Cdse Quantum Dots ◽  
Optimal Conditions ◽  
Cdse Qds ◽  
Relative Standard ◽  
Sensitivity And Selectivity

A simple route to the production of high-quality CdSe quantum dots (QDs) is presented. The characterization of CdSe QDs was measured by Zetasizer Nano ZS, ultraviolet-visible spectoscopy and fluorospectrophotometer. The CdSe QDs were decorated by 3-Aminobenzeneboronic acid to obtain good fluorescent characteristic. Under the optimal conditions, the decreased normalized absorbance was linear to the concentration of glucose from 1.0×10−7 to 2.9×10−6 mol·L-1with a detection limit of 5.0´10-8mol·L-1. The relative standard deviation (RSD) for the determination of 1.0×10-7mol·L-1was 1.4 % by 11 replicate determination. In this paper, the fluorescent behavior of glucose with the decorated CdSe QDs was studied, and it is found that the system has a high sensitivity and selectivity for analysis of glucose.

scholarly journals The Use of Chemically Precipitated Lead Sulfide Thin Films as a Material for Sensors Meant for Lead Content in Water Media Control

2011 ◽  
pp. 64-73
Author(s):  
Keyword(s):  
Thin Films ◽  
Lead Sulfide ◽  
High Sensitivity ◽  
Ion Selective Electrodes ◽  
Analytical Control ◽  
The Novel ◽  
Media Control ◽  
Primary Converter ◽  
Water Media ◽  
Sensitivity And Selectivity

Surface-sensitive properties of the sensor elements based on semiconductor thin fills of lead sulfide have been studied in order to use them as primary converter for ecological/analytical control of water media. Distinctive feater of the novel sensor elements is their high sensitivity and selectivity that five and more times exceeds similar properties of commercial ion-selective electrodes.

Synthesis and Characterization of the Perthiatriarylmethyl Radical and Its Dendritic Derivatives with High Sensitivity and Selectivity to Superoxide Radical

2018 ◽  
Vol 24 (27) ◽  
pp. 6958-6967 ◽  
Author(s):  
Xiaoli Tan ◽  
Shanqing Tao ◽  
Wenbo Liu ◽  
Antal Rockenbauer ◽  
Frederick A. Villamena ◽  
...  
Keyword(s):  
Superoxide Radical ◽  
High Sensitivity ◽  
Synthesis And Characterization ◽  
Sensitivity And Selectivity

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

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