scholarly journals Phenylalanine Gold Nanoclusters as Sensing Platform for π-π Interfering Molecules: A Case Study of Lodide

2021 ◽  
Author(s):  
Amir Amiri-Sadeghan ◽  
Tayebeh Zohrabi ◽  
Ali Dinari ◽  
Reza Khodarahmi ◽  
Saman Hosseinkhani ◽  
...  
Keyword(s):  
Surrounding Medium ◽  
Gold Nanoclusters ◽  
Building Blocks ◽  
Aromatic Rings ◽  
Nano Structure ◽  
Sensing Applications ◽  
Sensing Platform ◽  
Self Assembled ◽  
Oxidized Products

Abstract The photo-physical properties of metal nano clusters are sensitive to their surrounding medium. Fluorescence enhancement, quenching, and changes in the emitted photon properties are usual events in the sensing applications using these nano materials. Combining this sensitivity with unique properties of self-assembled structures opens new opportunities for sensing applications. Here, we synthesized gold nanoclusters by utilizing phenylalanine amino acid as both capping and reducing molecule. Phenylalanine is able to self-assemble to rod-shaped nano structure in which the π-π interaction between the aromatic rings is a major stabilizing force. Any substance as iodide anion or molecule that is able to weaken this interaction influence the fluorescence of metal nano-clusters. Since the building blocks of the self-assembled structure are made through the reaction of gold ions and phenylalanine, the oxidized products and their effect of sensing features are explored.

Self Assembled Patterns of Gold Nanoclusters in Silicon (100) Produced by Metal Vapour Vacuum Arc Ion Implantation

2006 ◽  
Vol 960 ◽  
Author(s):  
Dinesh Kumar Venkatachalam ◽  
Dinesh Kumar Sood ◽  
Suresh Kumar Bhargava
Keyword(s):  
Ion Implantation ◽  
Gold Nanoclusters ◽  
Building Blocks ◽  
Implantation Dose ◽  
Vacuum Arc ◽  
Critical Threshold ◽  
Metal Vapour ◽  
Tentative Model ◽  
Solid Substrates ◽  
Self Assembled

ABSTRACTSelf assembled gold nanoclusters are attractive building blocks for future nanoscale sensors and optical devices due to their exciting catalytic properties. Recently several methods have been employed to produce nanoclusters on solid substrates, which result in a random spatial distribution of the clusters. In this work, we have achieved ordered circular patterns of gold nanoclusters in Silicon (100) substrates by Au ion implantation followed by thermal annealing. This unique phenomenon is observed only above a critical threshold implantation dose and anneal temperature. Based on a systematic study (SEM, XTEM and XRD) of the growth and morphology of the nanoclusters, we propose a tentative model for the formation mechanism of this unusual self-assembled pattern.

scholarly journals Controlled Formation of Catalytic and Emissive Gold Nanoclusters with a Synthetic Self-Assembled Protein Toroid

2020 ◽  
Author(s):  
David Bouzada ◽  
Ester Polo ◽  
Elena López ◽  
Yolanda Pérez ◽  
Cristian Vidal ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Self Assembly ◽  
Solid Phase ◽  
Recombinant Expression ◽  
Solid Phase Peptide Synthesis ◽  
Gold Nanoclusters ◽  
Building Blocks ◽  
Biophysical Characterization ◽  
Self Assembled

<div>Self-assembled proteins are privileged building blocks for the bottom-up organization of matter at the nanoscale. However, since most proteins are very large, they have to be produced by recombinant expression, which is less versatile and flexible than chemical synthesis. Here, we show that we can bridge the potential of proteins for nanofabrication with the simplicity and versatility of solid-phase peptide synthesis by relying on the self-assembly of the viral protein gp23.1, a small 50-residue protein that oligomerizes in solution to form a stable toroidal hexamer. We report the chemical synthesis and basic biophysical characterization of a gp23.1 mutant and show that its self-assembled hexamer templates the formation of highly monodisperse gold nanoclusters of about 1.3 nm inside its central cavity. The resulting nanoclusters show catalytic activity in cycloisomerization reactions as well as luminescence emission. This work demonstrates the versatility of this small self- assembled ring protein for a variety of nanotechnological applications.</div>

scholarly journals Controlled Formation of Catalytic and Emissive Gold Nanoclusters with a Synthetic Self-Assembled Protein Toroid

2020 ◽  
Author(s):  
David Bouzada ◽  
Ester Polo ◽  
Elena López ◽  
Yolanda Pérez ◽  
Cristian Vidal ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Self Assembly ◽  
Solid Phase ◽  
Recombinant Expression ◽  
Solid Phase Peptide Synthesis ◽  
Gold Nanoclusters ◽  
Building Blocks ◽  
Biophysical Characterization ◽  
Self Assembled

<div>Self-assembled proteins are privileged building blocks for the bottom-up organization of matter at the nanoscale. However, since most proteins are very large, they have to be produced by recombinant expression, which is less versatile and flexible than chemical synthesis. Here, we show that we can bridge the potential of proteins for nanofabrication with the simplicity and versatility of solid-phase peptide synthesis by relying on the self-assembly of the viral protein gp23.1, a small 50-residue protein that oligomerizes in solution to form a stable toroidal hexamer. We report the chemical synthesis and basic biophysical characterization of a gp23.1 mutant and show that its self-assembled hexamer templates the formation of highly monodisperse gold nanoclusters of about 1.3 nm inside its central cavity. The resulting nanoclusters show catalytic activity in cycloisomerization reactions as well as luminescence emission. This work demonstrates the versatility of this small self- assembled ring protein for a variety of nanotechnological applications.</div>

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

scholarly journals Attrition as a bottom-up pathway to subnational democratization

2021 ◽  
pp. 019251212110192
Author(s):  
Trix van Mierlo
Keyword(s):  
Civil Society ◽  
Field Research ◽  
Building Blocks ◽  
The Philippines ◽  
Causal Process ◽  
Bottom Up ◽  
System A ◽  
Extensive Field ◽  
Democratic System

Oftentimes, democracy is not spread out evenly over the territory of a country. Instead, pockets of authoritarianism can persist within a democratic system. A growing body of literature questions how such subnational authoritarian enclaves can be democratized. Despite fascinating insights, all existing pathways rely on the actions of elites and are therefore top-down. This article seeks to kick-start the discussion on a bottom-up pathway to subnational democratization, by proposing the attrition mechanism. This mechanism consists of four parts and is the product of abductive inference through theory-building causal process tracing. The building blocks consist of subnational democratization literature, social movement theory, and original empirical data gathered during extensive field research. This case study focuses on the ‘Dynasty Slayer’ in the province of Isabela, the Philippines, where civil society actors used the attrition mechanism to facilitate subnational democratization. This study implies that civil society actors in subnational authoritarian enclaves have agency.

Building a Personal Brand as a CEO: A Case Study of Vivy Yusof, the Cofounder of FashionValet and the dUCk Group

SAGE Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 215824402110302
Author(s):  
Nor Hasliza Md Saad ◽  
Zulnaidi Yaacob
Keyword(s):  
Social Media ◽  
Building Blocks ◽  
Media Content ◽  
Fashion Industry ◽  
Personal Brand ◽  
Branding Strategies ◽  
Social Media Presence ◽  
Personal Branding ◽  
The Masses

Social media is a new platform for CEOs to build their image and create a strong personal brand to represent themselves and their company. This research examines an outstanding Malaysian fashion icon and social media–savvy businesswoman with over a million followers on Instagram, Vivy Yusof, the youngest Malaysian e-commerce mogul and an example of a successful CEO who has used personal branding to build an empire in the fashion industry. The objectives of this research are to identify the type of messages Vivy Yusof communicates to her audience through her personal Instagram posts and to identify the ways Vivy Yusof’s audience engages with her posts on Instagram. Her Instagram post content is classified using the Honeycomb framework that comprises seven functional building blocks, namely, presence, relationships, reputation, groups, identity, conversations, and sharing. In this study, the content of Vivy Yusof’s Instagram posts is categorized by how she focuses on the various functional building blocks in her posts and the implications these blocks have on how her audience interacts with the posts. Her social media presence confirms the importance of CEO personal branding because of her role and influence on the masses evidenced by the willingness of her followers to interact (through likes and comments) and engage with her posts on any subject matter, relating either to her business or personal life. The study contributes to a growing body of literature on personal branding strategies by shedding light on the association between content strategies and engagement with social media content.

scholarly journals Nanomechanics of self-assembled DNA building blocks

Nanoscale ◽  
2021 ◽  
Author(s):  
Michael Penth ◽  
Kordula Schellnhuber ◽  
Roland Bennewitz ◽  
Johanna Blass
Keyword(s):  
Structural Dynamics ◽  
Force Spectroscopy ◽  
Building Blocks ◽  
Dna Origami ◽  
Self Assembled ◽  
High Flexibility

Massive parallel force spectroscopy reveals a surprisingly high flexibility for DNA constructs used in DNA origami. The high flexibility is attributed to the structural dynamics of DNA self-assemblies.

scholarly journals Self-Assembly of Shape-Tunable Oblate Colloidal Particles into Orientationally Ordered Crystals, Glassy Crystals and Plastic Crystals

Soft Matter ◽  
2021 ◽  
Author(s):  
Jiawei Lu ◽  
Xiangyu Bu ◽  
Xinghua Zhang ◽  
Bing Liu
Keyword(s):  
Crystal Structures ◽  
Self Assembly ◽  
Colloidal Particles ◽  
Building Blocks ◽  
Fundamental Question ◽  
The Self ◽  
Plastic Crystals ◽  
Self Assembled ◽  
Glassy Crystals ◽  
The Relationship

The shapes of colloidal particles are crucial to the self-assembled superstructures. Understanding the relationship between the shapes of building blocks and the resulting crystal structures is an important fundamental question....

scholarly journals Hybrid Grating in Reduced-Diameter Fiber for Temperature-Calibrated High-Sensitivity Refractive Index Sensing

2019 ◽  
Vol 9 (9) ◽  
pp. 1923
Author(s):  
Biqiang Jiang ◽  
Zhen Hao ◽  
Dingyi Feng ◽  
Kaiming Zhou ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Simultaneous Measurement ◽  
Surrounding Medium ◽  
High Sensitivity ◽  
Fiber Grating ◽  
Bragg Resonance ◽  
Core Mode ◽  
Promising Alternative ◽  
Sensing Applications ◽  
Highly Sensitive

We propose and experimentally demonstrate a hybrid grating, in which an excessively tilted fiber grating (Ex-TFG) and a fiber Bragg grating (FBG) were co-inscribed in a reduced-diameter fiber (RDF). The hybrid grating showed strong resonances due to coupling among core mode and a set of polarization-dependent cladding modes. This coupling showed enhanced evanescent fields by the reduced cladding size, thus allowing stronger interaction with the surrounding medium. Moreover, the FBG’s Bragg resonance confined by the thick cladding was exempt from the change of the surrounding medium’s refractive index (RI), and then the FBG can work as a temperature compensator. As a result, the Ex-TFG in RDF promised a highly sensitive RI measurement, with a sensitivity up to ~1224 nm/RIU near the RI of 1.38. Through simultaneous measurement of temperature and RI, the temperature dependence of water’s RI is then determined. Therefore, the proposed hybrid grating with a spectrum of multi-peaks embedded with a sharp Bragg resonance is a promising alternative for the simultaneous measurement of multi-parameters for many RI-based sensing applications.

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