scholarly journals Effective replacement of cetyltrimethylammonium bromide (CTAB) by mercaptoalkanoic acids on gold nanorod (AuNR) surfaces in aqueous solutions

Nanoscale ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 658-668 ◽  
Author(s):  
Rafael del Caño ◽  
Jose M. Gisbert-González ◽  
Jose González-Rodríguez ◽  
Guadalupe Sánchez-Obrero ◽  
Rafael Madueño ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Gold Nanorods ◽  
Ligand Exchange ◽  
Cetyltrimethylammonium Bromide ◽  
Gold Nanorod ◽  
Experimental Conditions ◽  
Seed Mediated ◽  
The Stability

The highly packed cetyltrimethylammonium bromide bilayer on the surface of gold nanorods synthesized by the seed-mediated procedure hampers the complete ligand exchange under experimental conditions that preserves the stability of the dispersions.

Removal of Cetyltrimethylammonium Bromide to Enhance the Biocompatibility of Au Nanorods Synthesized by a Modified Seed Mediated Growth Process

2008 ◽  
Vol 8 (9) ◽  
pp. 4670-4674 ◽  
Author(s):  
Byung-Sang Choi ◽  
Muhammad Iqbal ◽  
Takhee Lee ◽  
Young Ha Kim ◽  
Giyoong Tae
Keyword(s):  
Gold Nanorods ◽  
Cetyltrimethylammonium Bromide ◽  
Growth Process ◽  
Complete Removal ◽  
Au Nanorods ◽  
Nir Absorption ◽  
Seed Mediated ◽  
The Stability ◽  
Growth Approach

Previously, we reported the synthesis of stable gold nanorods with higher aspect ratio (∼15–20) and more enhanced uniformity by a modified seed mediated growth approach using a binary surfactant system consisting of CTAB and Pluronic F-127. For the in vivo application of gold nanorods, the removal of CTABs that are strongly bound on prepared Au nanorods is necessary due to their cytotoxicity. Use of heat or acid at various conditions was performed to achieve the complete removal of CTAB from the synthesized Au nanorods while maintaining their stability. Here, we report the appropriate conditions for both treatments that can remove CTAB efficiently without hampering the stability of Au nanorods. After the removal of CTAB, Pluronic F-127 was added additionally for the stabilization and further potential functionalization of Au nanorods to make useful for various applications. VIS-NIR absorption spectroscopy, SEM, TEM, and FTIR were used for characterization.

scholarly journals Investigations of ternary complexes of Co(II) and Ni(II) with thiodiacetate anion and 1,10-phenanthroline or 2,2’-bipyridine in aqueous solutions

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Dariusz Wyrzykowski ◽  
Joanna Pranczk ◽  
Dagmara Jacewicz ◽  
Aleksandra Tesmar ◽  
Bogusław Pilarski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Substitution Reactions ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Hydroxo Complexes ◽  
Binary Complexes ◽  
Vis Spectroscopy ◽  
Potentiometric Titration Method ◽  
The Stability ◽  
Ph Range

AbstractA potentiometric titration method (PT) and a stopped-flow kinetic technique monitored by a UV−Vis spectroscopy have been used to characterize the stability of series of Co(II)- and Ni(II)-thiodiacetato complexes, M(TDA), in the presence of 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) in aqueous solutions. The stability constants of the binary (1:1), ternary (1:1:1) as well as the resulting hydroxo complexes were evaluated and compared to the corresponding oxydiacetate complexes. Based on the species distribution as a function of pH the relative predominance of the species in the system over a pH range was discussed. Furthermore, the kinetic measurements of the substitution reactions of the aqua ligands to phen or bipy in the coordination sphere of the binary complexes M(TDA) were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (0.2–0.5 mM). The kinetic stability of the M(TDA) complexes was discussed in relation to the experimental conditions and the kind of the auxiliary ligands (phen/bipy). Moreover, the influence of the type of primary ligand (thiodiacetate/oxydiacetate) on the substitution rate of the auxiliary ligands was also compared.

The affinity of aldehydic compounds to complex formation. Nickel(II) and cobalt(II) complexes with 2-pyridinecarboxaldehyde

1977 ◽  
Vol 55 (14) ◽  
pp. 2613-2619 ◽  
Author(s):  
M. S. El-Ezaby ◽  
M. A. El-Dessouky ◽  
N. M. Shuaib
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Metal Ion ◽  
Experimental Conditions ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Complex Equilibria ◽  
The Stability ◽  
Hydroxy Groups

The interactions of Ni(II) and Co(II) with 2-pyridinecarboxaldehyde have been investigated in aqueous solutions at μ = 0.10 M (KNO3) at 30 °C. The stability constants of different complex equilibria have been determined using potentiometric methods. Spectrophotometric methods were also used in the case of the nickel(II) – 2-pyridinecarboxaldehyde system. It was concluded that nickel(II) and cobalt(II), analogous to copper(II), enhance hyrdation of 2-pyridinecarboxaldehyde prior to deprotonation of one of the geminal hydroxy groups. Complex species of 1:1 as well as 1:2 metal ion to ligand composition exist under the experimental conditions used.

scholarly journals Two-step synthesis of high aspect ratio gold nanorods

2006 ◽  
Vol 4 (1) ◽  
pp. 160-165 ◽  
Author(s):  
Tom Mortier ◽  
André Persoons ◽  
Thierry Verbiest
Keyword(s):  
Aspect Ratio ◽  
Gold Nanorods ◽  
High Aspect Ratio ◽  
Cetyltrimethylammonium Bromide ◽  
Surfactant Concentration ◽  
Synthetic Method ◽  
Aspect Ratios ◽  
Seed Mediated

AbstractWe describe a very simple, two-step synthetic method to prepare gold nanorods with extremely high aspect ratios (> 20) and average lengths of more than 1000 nm. The method is based on a seed-mediated growth in presence of the surfactant cetyltrimethylammonium bromide. The length and aspect ratios of the nanorods can be manipulated by varying the surfactant concentration.

Synthesis of Chitosan-Stabilized Gold Nanorod Using Tripolyphosphate

2013 ◽  
Vol 652-654 ◽  
pp. 250-253
Author(s):  
Hua Nan Guan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Chemical Synthesis ◽  
Gold Nanorods ◽  
Gold Nanorod ◽  
Gold Salt ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Seed Mediated

An improvement in the previously reported seed-mediated chemical synthesis of gold nanorods (GNRs) is reported. Gold nanoparticles were prepared by reducing gold salt with a polysaccharide, chitosan, in the presence of tripolyphosphate (TPP). The obtained gold nanoparticles were characterized with UV-vis spectroscopy and transmission electron microscopy. The study shows that TPP plays an important role in the formation of GNRs.

scholarly journals Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

2019 ◽  
Vol 15 ◽  
pp. 1407-1415 ◽  
Author(s):  
Maximilian Niehues ◽  
Patricia Tegeder ◽  
Bart Jan Ravoo
Keyword(s):  
Gold Nanorods ◽  
Self Assembly ◽  
Ligand Exchange ◽  
Cetyltrimethylammonium Bromide ◽  
Complete Removal ◽  
Tetraethylene Glycol ◽  
Functionalized Nanoparticles ◽  
Organic Hybrid ◽  
Cross Linker ◽  
End To End

We propose a two-step ligand exchange for the selective end-functionalization of gold nanorods (AuNR) by thiolated cyclodextrin (CD) host molecules. As a result of the complete removal of the precursor capping agent cetyltrimethylammonium bromide (CTAB) by a tetraethylene glycol derivative, competitive binding to the host cavity was prevented, and reversible, light-responsive assembly and disassembly of the AuNR could be induced by host–guest interaction of CD on the nanorods and a photoswitchable arylazopyrazole cross-linker in aqueous solution. The end-to-end assembly of AuNR could be effectively controlled by irradiation with UV and visible light, respectively, over four cycles. By the introduction of AAP, previous disassembly limitations based on the photostationary states of azobenzenes could be solved. The combination photoresponsive interaction and selectively end-functionalized nanoparticles shows significant potential in the reversible self-assembly of inorganic–organic hybrid nanomaterials.

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

Effect of aspect ratio on the chirality of gold nanorods prepared through conventional seed-mediated growth method

2021 ◽  
Vol 1152 ◽  
pp. 338277
Author(s):  
Xiaojuan Zhou ◽  
Qiang Liu ◽  
Xiaoyu Shi ◽  
Chunli Xu ◽  
Baoxin Li
Keyword(s):  
Aspect Ratio ◽  
Gold Nanorods ◽  
Growth Method ◽  
Seed Mediated

scholarly journals Effective Separation of Prime Olefins from Gas Stream Using Anion Pillared Metal Organic Frameworks: Ideal Adsorbed Solution Theory Studies, Cyclic Application and Stability

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 510
Author(s):  
Majeda Khraisheh ◽  
Fares. Almomani ◽  
Gavin Walker
Keyword(s):  
Breakthrough Curves ◽  
Isotherm Models ◽  
Regeneration Ability ◽  
Solution Theory ◽  
Experimental Conditions ◽  
Ideal Adsorbed Solution Theory ◽  
Adsorbed Solution ◽  
The Stability ◽  
Adsorption Desorption ◽  
Adsorbed Solution Theory

The separation of C3H4/C3H6 is one of the most energy intensive and challenging operations, requiring up to 100 theoretical stages, in traditional cryogenic distillation. In this investigation, the potential application of two MOFs (SIFSIX-3-Ni and NbOFFIVE-1-Ni) was tested by studying the adsorption–desorption behaviors at a range of operational temperatures (300–360 K) and pressures (1–100 kPa). Dynamic adsorption breakthrough tests were conducted and the stability and regeneration ability of the MOFs were established after eight consecutive cycles. In order to establish the engineering key parameters, the experimental data were fitted to four isotherm models (Langmuir, Freundlich, Sips and Toth) in addition to the estimation of the thermodynamic properties such as the isosteric heats of adsorption. The selectivity of the separation was tested by applying ideal adsorbed solution theory (IAST). The results revealed that SIFSIX-3-Ni is an effective adsorbent for the separation of 10/90 v/v C3H4/C3H6 under the range of experimental conditions used in this study. The maximum adsorption reported for the same combination was 3.2 mmolg−1. Breakthrough curves confirmed the suitability of this material for the separation with a 10-min gab before the lighter C3H4 is eluted from the column. The separated C3H6 was obtained with a 99.98% purity.

Sign in / Sign up

Export Citation Format

Share Document