scholarly journals Synthesis of Well-Defined Gold Nanoparticles Using Pluronic: The Role of Radicals and Surfactants in Nanoparticles Formation

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1553 ◽  
Author(s):  
Marina Sokolsky-Papkov ◽  
Alexander Kabanov
Keyword(s):  
Gold Nanoparticles ◽  
Self Assembly ◽  
Building Blocks ◽  
Pluronic F127 ◽  
Hydroxyl Groups ◽  
Chloroauric Acid ◽  
Optimized Conditions ◽  
Phosphate Buffered Saline ◽  
Insight Into

Synthesis of gold nanoparticles (GNP) by reacting chloroauric acid (HAuCl4) and Pluronic F127 was thoroughly investigated. The rate of reduction of HAuCl4 and the yield and morphology of GNP strongly depended on the concentration of the reactants and sodium chloride, as well as pH and temperature. Upon completion of the reaction heterogeneous mixtures of small GNP of defined shape and Pluronic aggregates were formed. GNP were separated from the excess of Pluronic by centrifugal filtration. Under optimized conditions the GNP were small (ca. 80 nm), uniform (PDI ~0.09), strongly negatively charged (ζ-potential −30 mV) and nearly spherical. They were stable in distilled water and phosphate-buffered saline. Purified GNP contained ~13% by weight of an organic component, yet presence of polypropylene oxide was not detected suggesting that Pluronic was not adsorbed on their surface. Analysis of the soluble products suggested that the copolymer undergoes partial degradation accompanied by cleavage of the C–O bonds and appearance of new primary hydroxyl groups. The reaction involves formation of free radicals and hydroperoxides depends on the oxygen concentration. GNP did not form at 4 °C when the micellization of Pluronic was abolished reinforcing the role of the copolymer self-assembly. In conclusion, this work provides insight into the mechanism of HAuCl4 reduction and GNP formation in the presence of Pluronic block copolymers. It is useful for improving the methods of manufacturing uniform and pure GNP that are needed as nanoscale building blocks in nanomedicine applications.

Role of Hydroxyl Groups in Low-Temperature CO Catalytic Oxidation over Zn4Si2O7(OH)2 Nanowire-Supported Gold Nanoparticles

2018 ◽  
Vol 122 (44) ◽  
pp. 25456-25466 ◽  
Author(s):  
Jing-Jing Li ◽  
Bao-Lin Zhu ◽  
Gui-Chang Wang ◽  
Zun-Feng Liu ◽  
Wei-Ping Huang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Low Temperature ◽  
Catalytic Oxidation ◽  
Hydroxyl Groups ◽  
Co Catalytic Oxidation ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Personal Values as a Building Block for Social Responsibility of Higher Education Institutions

2017 ◽  
pp. 119-142 ◽  
Author(s):  
Zlatko Nedelko ◽  
Vojko Potocan ◽  
Nikša Alfirević
Keyword(s):  
Higher Education ◽  
Social Responsibility ◽  
Community Involvement ◽  
Higher Education Institutions ◽  
Personal Values ◽  
Building Blocks ◽  
Starting Point ◽  
Core Mission ◽  
Insight Into

The purpose of this chapter is to examine the role of personal values for social responsibility (SR) of higher education. Besides the core mission of higher education to create, transfer and preserve knowledge in society, the idea of SR has gained its importance also in institutions of higher education. SR has many drivers, among which personal values are considered as one of the key building blocks for SR. For enhancing SR, higher education institutions should also develop stronger ties with the community. The chapter provides an insight into discussion about community involvement of higher education, into the role of personal values for shaping SR of higher education institutions and explain how personal values can help to enhance community and social involvement of higher education. Findings may be a starting point for re-thinking and/or establishing strategies for achieving higher level of SR in higher education institutions and enhancing the link with the community.

Colorimetric Study of the Interaction Between Gold Nanoparticles and a Series of Amino Acids

2008 ◽  
Vol 8 (1) ◽  
pp. 353-357 ◽  
Author(s):  
Xiaoli Zhu ◽  
Qianlu Yang ◽  
Junyi Huang ◽  
Iwao Suzuki ◽  
Genxi Li
Keyword(s):  
Amino Acids ◽  
Gold Nanoparticles ◽  
Self Assembly ◽  
Ph Value ◽  
Hydroxyl Groups ◽  
Side Chains ◽  
Interesting Effect ◽  
Colorimetric Study

Study of the interaction between gold nanoparticles and a series of amino acids is reported in this paper. Amino acids with thiol, amine, or hydroxyl groups in their side chains are proven to make gold nanoparticles self-assemble under certain conditions. There is a progression of the effect on self-assembly of gold nanoparticles from hydroxyl < amine < thiol. Meanwhile, concentration of amino acids and the pH value of the solution have been found to be important for amino acids to exert the interesting effect on self-assembly of the nanoparticles.

scholarly journals The Role of Proteins in Biosilicification

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Daniel Otzen
Keyword(s):  
Self Assembly ◽  
Organic Matrix ◽  
Specific Protein ◽  
Colloidal Systems ◽  
Protein Properties ◽  
Modified Peptides ◽  
Fundamental Biology ◽  
Living Organisms ◽  
Insight Into

Although the use of silicon dioxide (silica) as a constituent of living organisms is mainly restricted to diatoms and sponges, the ways in which this process is controlled by nature continue to inspire and fascinate. Both diatoms and sponges carry out biosilificiation using an organic matrix but they adopt very different strategies. Diatoms use small and heavily modified peptides called silaffins, where the most characteristic feature is a modulation of charge by attaching long chain polyamines (LCPAs) to lysine groups. Free LCPAs can also cooperate with silaffins. Sponges use the enzyme silicatein which is homologous to the cysteine protease cathepsin. Both classes of proteins form higher-order structures which act both as structural templates and mechanistic catalysts for the polycondensation reaction. In both cases, additional proteins are continuously being discovered which modulate the process further. This paper concentrates on the role of these proteins in the biosilification process as well as in various applications, highlighting areas where focus on specific protein properties may provide further insight. The field of biosilification is a crossroads of different disciplines, where insight into the energetics and mechanisms of molecular self-assembly combine with fundamental biology, complex multicomponent colloidal systems, and an impressive array of potential technological applications.

The Role of Hydroxyl Groups in the Self-Assembly of Long Chain Alkylhydroxyl Carboxylic Acids on Mica

2008 ◽  
Vol 112 (43) ◽  
pp. 16968-16972 ◽  
Author(s):  
José J. Benítez ◽  
José A. Heredia-Guerrero ◽  
Francisco M. Serrano ◽  
Antonio Heredia
Keyword(s):  
Carboxylic Acids ◽  
Self Assembly ◽  
The Self ◽  
Hydroxyl Groups ◽  
Long Chain

scholarly journals Porous Colloidal Hydrogels Formed by Coordination-Driven Self-Assembly of Charged Metal-Organic Polyhedra

2021 ◽  
Author(s):  
Zaoming Wang ◽  
Gavin Craig ◽  
alexandre legrand ◽  
Frederik Haase ◽  
Saori Minami ◽  
...  
Keyword(s):  
Self Assembly ◽  
Soft Materials ◽  
Building Blocks ◽  
Internal Cavity ◽  
Hydroxyl Groups ◽  
Gel Formation ◽  
Gas Sorption ◽  
Coordination Cages ◽  
Metal Organic ◽  
Supramolecular Polymerization

Introduction of porosity into supramolecular gels endows soft materials with functionalities for molecular encapsulation, release, separation and conversion. Metal-organic polyhedra (MOPs), discrete coordination cages containing an internal cavity, have recently been employed as building blocks to construct polymeric gel networks with potential porosity. However, most of the materials can only be synthesized in organic solvents, and the examples of porous, MOP-based hydrogels are scarce. Here, we demonstrate the fabrication of porous hydrogels based on [Rh<sub>2</sub>(OH-bdc)<sub>2</sub>]<sub>12</sub>, a rhodium-based MOP containing hydroxyl groups on its periphery (OH-bdc = 5-hydroxy-1,3-benzenedicarboxylate). By simply deprotonating [Rh<sub>2</sub>(OH-bdc)<sub>2</sub>]<sub>12</sub> with the base NaOH, the supramolecular polymerization between MOPs and organic linkers can be induced in the aqueous solution, leading to the kinetically controllable formation of hydrogels with hierarchical colloidal networks. When heating the deprotonated MOP, Na<sub>x</sub>[Rh<sub>24</sub>(O-bdc)<sub>x</sub>(OH-bdc)<sub>24-x</sub>], to induce gelation, the MOP was found to partially decompose, affecting the mechanical property of the resulting gels. By applying a post-synthetic deprotonation strategy, we show that the deprotonation degree of the MOP can be altered after the gel formation without serious decomposition of the MOPs. Gas sorption measurements confirmed the permanent porosity of the corresponding aerogels obtained from these MOP-based hydrogels, showing potentials for applications in gas sorption and catalysis.

scholarly journals Role of Surfactant in the Formation of Gold Nanoparticles in Aqueous Medium

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Abhishek Das ◽  
Ridhima Chadha ◽  
Nandita Maiti ◽  
Sudhir Kapoor
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Medium ◽  
Sodium Dodecyl ◽  
Chloroauric Acid ◽  
Synthesis Mechanism ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Mediated Reduction

The stability of gold nanoparticles is a major issue which decides their impending usage in nanobiotechnological applications. Often biomimetically synthesized nanoparticles are deemed useless owing to their instability in aqueous medium. So, surfactants are used to stabilize the nanoparticles. But does the surfactant only stabilize by being adsorbed to the surface of the nanoparticles and not play significantly in moulding the size and shape of the nanoparticles? Keeping this idea in mind, gold nanoparticles (GNPs) synthesized by l-tryptophan (Trp) mediated reduction of chloroauric acid (HAuCl4) were stabilized by anionic surfactant, sodium dodecyl sulphate (SDS), and its effect on the moulding of size and properties of the GNPs was studied. Interestingly, unlike most of the gold nanoparticles synthesis mechanism showing saturation growth mechanism, inclusion of SDS in the reaction mixture for GNPs synthesis resulted in a bimodal mechanism which was studied by UV-Vis spectroscopy. The mechanism was further substantiated with transmission electron microscopy. Zeta potential of GNPs solutions was measured to corroborate stability observations recorded visually.

An insight into the role of riboflavin ligand in the self-assembly of poly(lactic-co-glycolic acid)-based nanoparticles – a molecular simulation and experimental approach

Soft Matter ◽  
2020 ◽  
Vol 16 (22) ◽  
pp. 5250-5260 ◽  
Author(s):  
Sima Rezvantalab ◽  
Mostafa Keshavarz Moraveji ◽  
Mohammad Khedri ◽  
Reza Maleki
Keyword(s):  
Molecular Simulation ◽  
Self Assembly ◽  
Targeted Delivery ◽  
Glycolic Acid ◽  
Experimental Approach ◽  
The Self ◽  
Insight Into

Nanoparticles (NPs) used for targeted delivery purposes are rapidly gaining importance in diagnostic and therapeutic fields.

Insight into the Role of Hydrogen Bonding in the Molecular Self-Assembly Process of Sulfamethazine Solvates

2017 ◽  
Vol 17 (12) ◽  
pp. 6151-6157 ◽  
Author(s):  
Xia Zhang ◽  
Ling Zhou ◽  
Chang Wang ◽  
Yang Li ◽  
Yanan Wu ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Assembly Process ◽  
Insight Into

Hydrogen bonded supramolecular structures: a further insight into the diamine-diol recognition and self-assembly

2000 ◽  
Vol 78 (6) ◽  
pp. 723-731 ◽  
Author(s):  
Stefano Roelens ◽  
Paolo Dapporto ◽  
Paola Paoli
Keyword(s):  
Molecular Recognition ◽  
Gas Phase ◽  
Self Assembly ◽  
Supramolecular Assembly ◽  
Supramolecular Structures ◽  
Unique Role ◽  
X Ray ◽  
Molecular Code ◽  
Insight Into

A new H-bonded supramolecular assembly of the diamine-diol family has been obtained from (1R,2R)-1,2-diaminocyclohexane (DAC) and (S)-1-phenyl-1,2-ethanediol (PED). The structure was characterized by single-crystal X-ray analysis and showed the typical architecture of DAC based assemblies, consisting of a three-stranded helicate coiling around a H-bonded core, with a predictable helicity sense determined by the configuration of DAC. The new assembly, while reconfirming the unique role of DAC as a powerful assembler of supramolecular structures, demonstrated that the C2 symmetry of diol partners employed so far is not essential for assembling helicates, although chirality is. In the case of the adduct between (1R,2R)-1,2-diaminocyclohexane and (2R,3R)-2,3-butanediol, molecular recognition and self-assembly have been shown to take place even in the absence of solvent, in the gas phase, where long crystals were formed by spontaneous organized aggregation of diamine-diol units. A thorough analysis of the results from the present and previous investigations has lead to a deeper understanding of the key features of the diamine-diol molecular code and of the requirements for recognition and assembly.Key words: supramolecular, hydrogen bonding, molecular recognition, self-assembly, diamines, diols.

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