scholarly journals TRYPTOFAN TRANSFORMATION DURING THE REACTION WITH TETRACHLOROAURIC ACID

2020 ◽  
pp. 30-34
Author(s):  
T. Makarenko ◽  
R. Linnik ◽  
M. Malysheva ◽  
Iu. Mukha ◽  
N. Vityuk ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Amino Acid ◽  
Spectral Characteristics ◽  
Kynurenine Pathway ◽  
Human Organism ◽  
Acid Oxidation ◽  
Actual Problem ◽  
Main Band ◽  
Au Nps ◽  
Positive Mode

Gold nanoparticles (Au NPs) are effective agents for early diagnostic and treatment of a variety of diseases, including cancer. However, initial components in the synthesis like surfactants, which are commonly used to stabilize nanoparticles, can produce toxic effects on living organisms. Thus, finding ways to reduce the toxicity of nanoscale preparations is an actual problem. In this regard the essential aminoacid tryptophan (Trp) is a promising reagent for the synthesis of Au NPs that can serve as a reducer of Au(ІІІ) ions and particle stabilizer. In this work, in order to increase the biocompatibility of the nanoscale system, the synthesis of gold nanoparticles was performed in the presence of Trp. The reaction between HAuCl4 and Trp proceeded in aqueous medium with neutral pH at different temperatures. Spectral characteristics of products formed in Au/Trp systems and were studied. In the absorption spectra the main band of Trp at 280 nm was shifted to 250 nm during the reaction; for all studied systems upon excitation of fluorescence with the wavelength of λex = 340 nm the maximum of the emission bands were observed at λem = 450 nm, while for initial tryptophan (λex = 280 nm) it was located at λex = 375nm. Mass spectra of Trp solution in positive mode contained the signal at 131 Da, that was characteristic for ionized indole moiety of amino acid. For supernatants of studied Au/Trp systems in positive mode signals of ionized fragments with masses of 118, 146 and 174 Da were observed. Based on the data it was revealed that amino acid oxidation proceeded through the formation of kynurenine or through the "kynurenine pathway", that corresponds to the metabolic conversion of amino acid in human organism and proves the biocompatibility of formed products.

scholarly journals Easy and fast in-situ functionalization of exfoliated 2D black phosphorus with gold nanoparticles

2021 ◽  
Author(s):  
Salvatore Moschetto ◽  
Andrea Ienco ◽  
Gabriele Manca ◽  
Manuel Serrano-Ruiz ◽  
Maurizio Peruzzini ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Black Phosphorus ◽  
Au Nps ◽  
In Situ Functionalization

Heterostructures of single- and few-layer black phosphorus (2D bP) functionalized with gold nanoparticles (Au NPs) have been recently reported in the literature, exploiting their intriguing properties and biocompatibility for catalytic,...

scholarly journals Continuous citrate‐capped gold nanoparticle synthesis in a two‐phase flow reactor

2021 ◽  
Author(s):  
Spyridon Damilos ◽  
Ioannis Alissandratos ◽  
Luca Panariello ◽  
Anand N. P. Radhakrishnan ◽  
Enhong Cao ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Residence Time ◽  
Flow Reactor ◽  
Phase Flow ◽  
Continuous Manufacturing ◽  
Two Phase ◽  
Process Yield ◽  
Au Nps ◽  
Manufacturing Platform

AbstractA continuous manufacturing platform was developed for the synthesis of aqueous colloidal 10–20 nm gold nanoparticles (Au NPs) in a flow reactor using chloroauric acid, sodium citrate and citric acid at 95 oC and 2.3 bar(a) pressure. The use of a two-phase flow system – using heptane as the continuous phase – prevented fouling on the reactor walls, while improving the residence time distribution. Continuous syntheses for up to 2 h demonstrated its potential application for continuous manufacturing, while live quality control was established using online UV-Vis photospectrometry that monitored the particle size and process yield. The synthesis was stable and reproducible over time for gold precursor concentration above 0.23 mM (after mixing), resulting in average particle size between 12 and 15 nm. A hydrophobic membrane separator provided successful separation of the aqueous and organic phases and collection of colloidal Au NPs in flow. Process yield increased at higher inlet flow rates (from 70 % to almost 100 %), due to lower residence time of the colloidal solution in the separator resulting in less fouling in the PTFE membrane. This study addresses the challenges for the translation of the synthesis from batch to flow and provides tools for the development of a continuous manufacturing platform for gold nanoparticles.Graphical abstract

Macroscopical monolayer films of ordered arrays of gold nanoparticles as SERS substrates for in-situ quantitative detection in aqueous solutions

Nanoscale ◽  
2021 ◽  
Author(s):  
Lixiang Xing ◽  
Cui Wang ◽  
Yi Cao ◽  
Jihui Zhang ◽  
Haibing Xia
Keyword(s):  
Gold Nanoparticles ◽  
Volume Fraction ◽  
Water Volume ◽  
Quantitative Detection ◽  
Monolayer Films ◽  
Au Nps ◽  
Sers Substrates ◽  
Ordered Arrays ◽  
Water Volume Fraction

In this work, macroscopical monolayer films of ordered arrays of gold nanoparticles (MMF-OA-Au NPs) are successfully prepared at the interfaces of toluene-diethylene glycol (DEG) with a water volume fraction of...

scholarly journals PSXI-31 Program Chair Poster Pick: Determination of the threonine requirement in adult and senior Labrador Retrievers using the indicator amino acid oxidation technique

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 321-322
Author(s):  
Jordan T Weil ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Craig N Coon
Keyword(s):  
Amino Acid ◽  
Control Diet ◽  
Genetic Selection ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Oxidation ◽  
Amino Acid Oxidation ◽  
Amino Acid Requirements ◽  
Indispensable Amino Acids ◽  
Nutrient Profiles ◽  
Labrador Retrievers

Abstract Although nutrient profiles for canines have been developed in the past, the need to update amino acid (AA) requirements has gained importance as genetic selection changes the recommended nutrients. Correctly feeding AA to canines can have enormous effects, considering a deficiency or excess of such nutrient can lead to weight loss, disease, or in some cases, death. Amino acid requirements can be determined through the nitrogen balance or indicator amino acid oxidation (IAAO) methods. In this experiment, the IAAO technique was used to determine the threonine (Thr) requirement in Labrador retrievers. A total of six dogs (6 adult and 6 senior) were subjected to six diets with varying levels of Thr, ranging from deficient to excess. Diets were formulated to 1.6x NRC values for all indispensable amino acids. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer AA was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a piecewise model of best fit (JMP® Pro 15). The segmented line regression showed that the Thr mean and population requirements were determined to be 1.21 ± 0.24 and 0.92 ± 0.17 g/1000kcal (mean ± 2SD) for adult and senior dogs, respectively. As the pet food industry becomes more specialized in diets relating to aging, and diseased canines, updating the amino acid requirements related to such animals is increasingly important.

Influence of pH and aurate/amino acid ratios on the tuneable optical features of gold nanoparticles and nanoclusters

2017 ◽  
Vol 532 ◽  
pp. 601-608 ◽  
Author(s):  
Edit Csapó ◽  
Ditta Ungor ◽  
Zoltán Kele ◽  
Péter Baranyai ◽  
Andrea Deák ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Amino Acid ◽  
Influence Of Ph

EFFECT OF PERACETIC ACID OXIDATION ON N-CONTAINING COMPONENTS OF HUMIC MATERIALS

1980 ◽  
Vol 60 (3) ◽  
pp. 541-548 ◽  
Author(s):  
M. SCHNITZER ◽  
D. A. HINDLE
Keyword(s):  
Amino Acid ◽  
Peracetic Acid ◽  
Amino Sugar ◽  
Chemical Oxidation ◽  
Acid Oxidation ◽  
Mild Oxidation ◽  
Total N ◽  
Different Types ◽  
Humic Materials ◽  
Insight Into

Three humic and one fulvic acid were degraded by mild chemical oxidation with peracetic acid, with special emphasis on the effects of this type of oxidation on N-containing components. The different types of N that were considered were NH4+-N, amino acid-N, amino sugar-N, NO2−-N + NO3−-N, and by difference from total N, "unknown" N. The behaviour toward mild chemical oxidation of all four preparations was essentially similar: there were decreases in mino acid-N, amino sugar-N and "unknown" N, increases in NH4+-N, NO2−-N + NO3−-N with one material, and in N-gases. The "unknown" N was not inert. Between 16.6 and 59.1% of the latter appeared to be converted, as a result of mild chemical oxidation, to NH3 and N-gases which were expelled from the systems. The results presented provide an insight into what happens to N-containing humic components as a result of mild oxidation.

scholarly journals Effects of Different Surfactant Charges on the Formation of Gold Nanoparticles by the LASiS Method

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2937
Author(s):  
Muhammad Zulfajri ◽  
Wei-Jie Huang ◽  
Genin-Gary Huang ◽  
Hui-Fen Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Laser System ◽  
Synthesis Process ◽  
Au Nps ◽  
Laser Fluences ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
532 Nm

The laser ablation synthesis in solution (LASiS) method has been widely utilized due to its significant prospects in laser microprocessing of nanomaterials. In this study, the LASiS method with the addition of different surfactant charges (cationic CTAB, nonionic TX-100, and anionic SDS) was used to produce Au NPs. An Nd:YAG laser system at 532 nm excitation with some synthetic parameters, including different laser fluences, ablation times, and surfactant concentrations was performed. The obtained Au NPs were characterized by UV-Vis spectroscopy, transmission electron microscopy, and zeta potential analyzer. The Au NPs exhibited the maximum absorption peak at around 520 nm for all samples. The color of Au NPs was changed from red to reddish by increasing the laser fluence. The surfactant charges also played different roles in the Au NPs’ growth during the synthesis process. The average sizes of Au NPs were found to be 8.5 nm, 5.5 nm, and 15.5 nm with the medium containing CTAB, TX-100, and SDS, respectively. Besides, the different surfactant charges induced different performances to protect Au NPs from agglomeration. Overall, the SDS and CTAB surfactants exhibited higher stability of the Au NPs compared to the Au NPs with TX-100 surfactant.

Boosting the Electrochemistry of Li2O2 in Lithium−Oxygen Batteries by Plasmon-induced Hot-Electron Injection

2021 ◽  
Author(s):  
Weixue Yang ◽  
Fei Li ◽  
Huali Liu ◽  
Zhen Li ◽  
Jiaqi Zhao ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Localized Surface Plasmon Resonance ◽  
Localized Surface Plasmon ◽  
Hot Electron ◽  
Au Nps ◽  
Hot Electron Injection ◽  
Lithium Oxygen Batteries

A photo-assisted Li−Oxygen (Li−O2) battery with Au/SnO2 (ASO) hybrid nanotubes as cathode and photocatalyst has been prepared. The localized surface plasmon resonance (LSPR) excitation of gold nanoparticles (Au NPs) can...

Sign in / Sign up

Export Citation Format

Share Document