scholarly journals Electrochemical Properties of Phytosynthesized Gold Nanoparticles for Electrosensing

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 311
Author(s):  
Natalia Yu. Stozhko ◽  
Maria A. Bukharinova ◽  
Ekaterina I. Khamzina ◽  
Aleksey V. Tarasov
Keyword(s):  
Antioxidant Activity ◽  
Gold Nanoparticles ◽  
Current Trend ◽  
Electrochemical Activity ◽  
Peak Potential ◽  
Synthesis Conditions ◽  
Catalytically Active ◽  
Good Biocompatibility ◽  
Ascorbic Acids ◽  
Comprehensive Study

Gold nanoparticles are widely used in electrosensing. The current trend is to phytosynthesize gold nanoparticles (phyto-AuNPs) on the basis of the “green” chemistry approach. Phyto-AuNPs are biologically and catalytically active, stable and biocompatible, which opens up broad perspectives in a variety of applications, including tactile, wearable (bio)sensors. However, the electrochemistry of phytosynthesized nanoparticles is not sufficiently studied. This work offers a comprehensive study of the electrochemical activity of phyto-AuNPs depending on the synthesis conditions. It was found that with an increase in the aliquot of the plant extract, its antioxidant activity (AOA) and pH, the electrochemical activity of phyto-AuNPs grows, which is reflected in the peak potential decrease and an increase in the peak current of phyto-AuNPs electrooxidation. It has been shown that AOA is an important parameter for obtaining phyto-AuNPs with desired properties. Electrodes modified with phyto-AuNPs have demonstrated better analytical characteristics than electrodes with citrate AuNPs in detecting uric and ascorbic acids under model conditions. The data about the phyto-AuNPs’ electrochemistry may be useful for creating highly effective epidermal sensors with good biocompatibility.

scholarly journals Optimization of Synthesis of Seleno-Sargassum fusiforme(Harv.) Setch. Polysaccharide by Response Surface Methodology, Its Characterization, and Antioxidant Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yu-Bin Ji ◽  
Fang Dong ◽  
Miao Yu ◽  
Long Qin ◽  
Dan Liu
Keyword(s):  
Antioxidant Activity ◽  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
Reaction Temperature ◽  
Sargassum Fusiforme ◽  
Synthesis Conditions ◽  
Optimum Reaction ◽  
Series Of Experiments

The response surface methodology was employed to optimize the synthesis conditions of seleno-Sargassum fusiforme(Harv.) Setch. polysaccharide. Three independent variables (reaction time, reaction temperature, and ratio of Na2SeO3to SFPSI) were tested. Furthermore, the characterization and antioxidant activity of Se-SFPSIin vivowere investigated. The result showed that the actual experimental Se content of Se-SFPSI was 3.352 mg/g at the optimum reaction conditions of reaction time 8 h, reaction temperature 71°C, and ratio of Na2SeO3to SFPSIB 1.0 g/g. A series of experiments showed that the characterization of Se-SFPSIB was significantly different from that of SFPSIB. Additionally, antioxidant activity assay indicated that the Se-SFPSIB could increase catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity of mice bearing tumor S180in blood, heart, and liver while decreasing malondialdehyde (MDA) levels. It can be concluded that selenylation is a feasible approach to obtain seleno-polysaccharide which was utilized as highly biological medicine or functional food.

scholarly journals Biosynthesized gold nanoparticles-doped hydroxyapatite as antibacterial and antioxidant nanocomposite

2021 ◽  
Author(s):  
Is Fatimah ◽  
Putwi Widya Citradewi ◽  
Amri Yahya ◽  
Bambang Nugroho ◽  
Habibi Hidayat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antioxidant Activity ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Dpph Scavenging Activity ◽  
Dpph Scavenging

Abstract The composite of green synthesized gold nanoparticles (Au NPs)-doped hydroxyapatite (HA) has been prepared. The gold nanoparticles were produced via bioreduction of HAuCl4 with Clitoria ternatea flower extract, and utilized in the synthesis of hydroxyapatite using Ca(OH)2 and ammonium diphosphate as precursor. The aim of this research is to study the structural analysis of the composite and antibacterial activity test toward Eschericia coli, Staphylococcus aureus, Klebsiela pneumoniae, and Streptococcus pyogenes. In addition, the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method. The monitoring of gold nanoparticles formation was conducted by UV–vis spectroscopy and particle size analyses, meanwhile the synthesized composite was studied using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that homogeneously dispersed gold nanoparticles in HA structure was obtained with the particle size ranging at 5-80 nm. The nanocomposite demonstrated antibacterial activity against tested bacteria. The nanocomposite expressed an antioxidant activity as shown by the DPPH scavenging activity of 66 and 58% at the concentration of 100 μg/mL and 50 μg/mL, respectively.

ANTIBODY CONJUGATES WITH GOLD NANOPARTICLES AS A COMPONENT OF IMMUNOCHROMATOGRAPHIC DIAGNOSTICUMS: THE INFLUENCE OF SYNTHESIS CONDITIONS ON THE COMPOSITION AND REACTIVITY

2020 ◽  
pp. 180-181
Author(s):  
N. Byzova ◽  
A. Zherdev ◽  
B. Dzantiev
Keyword(s):  
Gold Nanoparticles ◽  
Immunochromatographic Test ◽  
C Reactive Protein ◽  
Synthesis Conditions ◽  
Reactive Protein ◽  
Test Systems ◽  
Antibody Conjugates ◽  
Analytical Reagents ◽  
D Dimer

A series of preparations of gold nanoparticles with diameters from 13 to 60 nm and their conjugates with antibodies (murine immunoglobulins of class G) of different composition were obtained. The composition of the conjugates and the amount of antibodies that retain their reactivity in an immobilized form are characterized. Using the example of immunochromatographic test systems for the detection of D-dimer and C-reactive protein, the effectiveness of conjugates as analytical reagents is compared.

Gold nanoparticles immobilised in a superabsorbent hydrogel matrix: facile synthesis and application for the catalytic reduction of toxic compounds

2020 ◽  
Vol 56 (8) ◽  
pp. 1263-1266 ◽  
Author(s):  
Hassan A. H. Alzahrani ◽  
Mark A. Buckingham ◽  
William P. Wardley ◽  
Richard D. Tilley ◽  
Nicholas Ariotti ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ionic Strength ◽  
Catalytic Reduction ◽  
High Ionic Strength ◽  
Facile Synthesis ◽  
Superabsorbent Hydrogel ◽  
Toxic Compounds ◽  
Hydrogel Matrix ◽  
Catalytically Active

AuNP easily synthesised inside bulk hydrogel spheres; stable and catalytically active, even in high ionic strength environments.

scholarly journals Correlation Study of Honey Regarding their Physicochemical Properties and Sugars and Cyclitols Content

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 34 ◽  
Author(s):  
Ileana Andreea Ratiu ◽  
Hossam Al-Suod ◽  
Małgorzata Bukowska ◽  
Magdalena Ligor ◽  
Bogusław Buszewski
Keyword(s):  
Electrical Conductivity ◽  
Antioxidant Activity ◽  
Statistical Analysis ◽  
Physicochemical Properties ◽  
Sugar Content ◽  
Correlation Study ◽  
Osmotic Effect ◽  
Defensive Role ◽  
Wide Range ◽  
Comprehensive Study

Honey is a natural sweetener, with an osmotic effect on microorganisms due to the increased sugar content and low amount of water. Cyclitols are minor constituents of honey. They play a defensive role in plants against unfavorable environmental conditions. Honey’s physicochemical properties can vary, resulting in a wide range of colors, flavors, scents, antioxidant activity, dissimilar values of pH, acidity, electrical conductivity, etc. Some literature regarding correlation between honey types is already available, but a comprehensive study displaying an ample evaluation of multifarious aspects is still needed. This study focuses on the correlation between 18 honey types, originating from 10 countries, collected during four years, summarizing a total of 38 samples. A total of 6 physicochemical properties and 18 target components (sugars and cyclitols) were considered as variables. A correlation analysis is presented between the investigated parameters and between honey types, together with the statistical analysis which allowed for observation of the clusters’ distribution according with the investigated variables.

scholarly journals DNA-mediated engineering of multicomponent enzyme crystals

2015 ◽  
Vol 112 (15) ◽  
pp. 4564-4569 ◽  
Author(s):  
Jeffrey D. Brodin ◽  
Evelyn Auyeung ◽  
Chad A. Mirkin
Keyword(s):  
Gold Nanoparticles ◽  
Protein Interactions ◽  
Building Blocks ◽  
Inorganic Nanoparticles ◽  
Protein Protein Interactions ◽  
Dna Interactions ◽  
Interparticle Interactions ◽  
Crystalline Materials ◽  
Catalytically Active ◽  
Surface Chemistries

The ability to predictably control the coassembly of multiple nanoscale building blocks, especially those with disparate chemical and physical properties such as biomolecules and inorganic nanoparticles, has far-reaching implications in catalysis, sensing, and photonics, but a generalizable strategy for engineering specific contacts between these particles is an outstanding challenge. This is especially true in the case of proteins, where the types of possible interparticle interactions are numerous, diverse, and complex. Herein, we explore the concept of trading protein–protein interactions for DNA–DNA interactions to direct the assembly of two nucleic-acid–functionalized proteins with distinct surface chemistries into six unique lattices composed of catalytically active proteins, or of a combination of proteins and DNA-modified gold nanoparticles. The programmable nature of DNA–DNA interactions used in this strategy allows us to control the lattice symmetries and unit cell constants, as well as the compositions and habit, of the resulting crystals. This study provides a potentially generalizable strategy for constructing a unique class of materials that take advantage of the diverse morphologies, surface chemistries, and functionalities of proteins for assembling functional crystalline materials.

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