scholarly journals Laser tailoring surface interactions, contact angles, drop topologies and the self-assembly of optical microwires

2013 ◽  
Vol 3 (2) ◽  
pp. 284 ◽  
Author(s):  
John Canning ◽  
Hadrien Weil ◽  
Masood Naqshbandi ◽  
Kevin Cook ◽  
Matthieu Lancry
Keyword(s):  
Self Assembly ◽  
Surface Interactions ◽  
Contact Angles ◽  
The Self ◽  
Laser Tailoring

Nanoparticles as template for porphyrin nanostructure growth

2019 ◽  
Vol 23 (04n05) ◽  
pp. 526-533 ◽  
Author(s):  
Mariana Hamer ◽  
Rolando M. Caraballo ◽  
Peter J. Eaton ◽  
Craig Medforth
Keyword(s):  
Self Assembly ◽  
Soret Band ◽  
Surface Interactions ◽  
Water Soluble ◽  
The Self ◽  
Stacking Interactions ◽  
Aromatic System ◽  
One Pot ◽  
Assembly Mechanism ◽  
Scattering Measurements

Porphyrins and metalloporphyrins are one of the most widely studied platforms for the construction of supramolecular structures. These compounds have an extended aromatic system that allows [Formula: see text]–[Formula: see text] stacking interactions which, together with hydrogen bonds, electrostatic forces and the formation of inter-metallic complexes arising from peripheral groups, offer a versatile platform to control the self-assembly mechanism. In this work, we present the study of nanostructures formed by self-assembly of the water-soluble porphyrins meso-tetra([Formula: see text]-methyl-4-pyridyl)porphyrin (TMPyP) and meso-tetra(4-sulfonatophenyl)porphyrin (TPPS) in the presence of hard nanotemplates. Different nanoparticles (silica, gold, and polystyrene), concentrations and synthetic procedures were explored. The obtained materials were characterized by SEM and AFM microscopies, UV-vis absorption spectroscopy and dynamic light scattering measurements. A clear modification of the SiO2 NP surface roughness using one-pot synthesis was observed. The results were variable depending on the porphyrin–surface interactions and concentrations used. At lower porphyrin concentrations, a shift of the Soret band was observed, while at higher concentrations, free NS were formed. This reflects a competition between surface and solution directed self-assembly.

scholarly journals Poly(styrene-co-butadiene) random copolymer thin films and nanostructures on a mica surface: morphology and contact angles of nanodroplets

Soft Matter ◽  
2017 ◽  
Vol 13 (36) ◽  
pp. 6152-6166 ◽  
Author(s):  
Jake McClements ◽  
Cosimo Buffone ◽  
Michael P. Shaver ◽  
Khellil Sefiane ◽  
Vasileios Koutsos
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Self Assembly ◽  
Random Copolymer ◽  
Contact Angles ◽  
The Self ◽  
Random Copolymers ◽  
Mica Surface ◽  
Molecular Weights

The self-assembly of poly(styrene-co-butadiene) random copolymers on mica surfaces was studied by varying solution concentrations and polymer molecular weights.

scholarly journals Seeding the Self-Assembly of DNA Origamis at Surfaces

2019 ◽  
Author(s):  
Huan Cao ◽  
Gary R. Abel ◽  
Qufei Gu ◽  
Gloria-Alexandra V. Gueorguieva ◽  
Yehan Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Homogeneous Solution ◽  
Surface Interactions ◽  
Dna Origami ◽  
The Self ◽  
Dynamic Surface ◽  
Surface Anchoring ◽  
New Strategy ◽  
Surface Confinement ◽  
Weak Surface

<b>Unlike supramolecular self-assembly methods that can organize many unique components into designer shapes in a homogeneous solution (<i>e.g</i>., DNA origami), only relatively simple, symmetric structures consisting of a few unique components have been self-assembled at solid surfaces. As the self-assembly process is confined to the surface/interface by mostly nonspecific attractive interactions, an open question is how these interfacial interactions affect multicomponent self-assembly. To gain a mechanistic understanding of the roles of surface environment in DNA origami self-assembly, here we studied the oligonucleotide-assisted folding of a long single-stranded DNA (ssDNA scaffold) that was end-tethered to a dynamic surface, which could actively regulate the DNA-surface interactions. The results showed that even weak surface attractions can lead to defective structures by inhibiting the merging of multiple domains into complete structures. A combination of surface anchoring and deliberate regulation of DNA-surface interactions allowed us to depart from the existing paradigm of surface confinement via nonspecific interactions and enabled DNA origami folding to proceed in a solution-like environment. Importantly, our new strategy retains the key advantages of surface-mediated self-assembly. Moreover, surface-anchored oligonucleotides could sequence-specifically initiate the growth of DNA origamis of specific sizes and shapes. Our work opens up new opportunities for encoding information into a surface and expressing the information into complex DNA surface architectures for potential nanoelectronics and nanophotonics applications. In addition, our new approach to surface confinement may facilitate the 2D self-assembly of other molecular components, such as proteins, as maintaining conformational freedom may be a general challenge in the self-assembly of complex structures at surfaces.</b><br><br>

scholarly journals Seeding the Self-Assembly of DNA Origamis at Surfaces

2019 ◽  
Author(s):  
Huan Cao ◽  
Gary R. Abel ◽  
Qufei Gu ◽  
Gloria-Alexandra V. Gueorguieva ◽  
Yehan Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Homogeneous Solution ◽  
Surface Interactions ◽  
Dna Origami ◽  
The Self ◽  
Dynamic Surface ◽  
Surface Anchoring ◽  
New Strategy ◽  
Surface Confinement ◽  
Weak Surface

<b>Unlike supramolecular self-assembly methods that can organize many unique components into designer shapes in a homogeneous solution (<i>e.g</i>., DNA origami), only relatively simple, symmetric structures consisting of a few unique components have been self-assembled at solid surfaces. As the self-assembly process is confined to the surface/interface by mostly nonspecific attractive interactions, an open question is how these interfacial interactions affect multicomponent self-assembly. To gain a mechanistic understanding of the roles of surface environment in DNA origami self-assembly, here we studied the oligonucleotide-assisted folding of a long single-stranded DNA (ssDNA scaffold) that was end-tethered to a dynamic surface, which could actively regulate the DNA-surface interactions. The results showed that even weak surface attractions can lead to defective structures by inhibiting the merging of multiple domains into complete structures. A combination of surface anchoring and deliberate regulation of DNA-surface interactions allowed us to depart from the existing paradigm of surface confinement via nonspecific interactions and enabled DNA origami folding to proceed in a solution-like environment. Importantly, our new strategy retains the key advantages of surface-mediated self-assembly. Moreover, surface-anchored oligonucleotides could sequence-specifically initiate the growth of DNA origamis of specific sizes and shapes. Our work opens up new opportunities for encoding information into a surface and expressing the information into complex DNA surface architectures for potential nanoelectronics and nanophotonics applications. In addition, our new approach to surface confinement may facilitate the 2D self-assembly of other molecular components, such as proteins, as maintaining conformational freedom may be a general challenge in the self-assembly of complex structures at surfaces.</b><br><br>

The Nature of Rapidly Extracted Phycocyanin from the Blue-Green Alga Plectonema Boryanum

1971 ◽  
Vol 29 ◽  
pp. 366-367
Author(s):  
M. Kessel ◽  
R. MacColl
Keyword(s):  
Self Assembly ◽  
Analytical Ultracentrifugation ◽  
Uranyl Acetate ◽  
The Self ◽  
Major Protein ◽  
Subunit Structure ◽  
Blue Green Alga ◽  
Thin Sections ◽  
Blue Green Algae ◽  
Cacodylate Buffer

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.

Interrelationship of the cellular distribution and secretion of regular structure (RS) protein in Bacillus licheniformis nm 105

1992 ◽  
Vol 50 (1) ◽  
pp. 712-713
Author(s):  
Xiaorong Zhu ◽  
Richard McVeigh ◽  
Bijan K. Ghosh
Keyword(s):  
Alkaline Phosphatase ◽  
Bacillus Licheniformis ◽  
Self Assembly ◽  
Gel Electrophoresis ◽  
Culture Supernatant ◽  
Regular Structure ◽  
The Self ◽  
Cellular Distribution ◽  
Structural Protein ◽  
Laboratory Cultures

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

Bottom-up Evolution from Disks to High-Genus Polymersomes

2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Chain Entanglement ◽  
Bottom Up ◽  
New Approach ◽  
High Genus ◽  
Transmission Electron ◽  
Minimal Radius ◽  
Stop Flow

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>

Bottom-up Evolution from Disks to High-Genus Polymersomes

2018 ◽  
Author(s):  
Claudia Contini ◽  
Russell Pearson ◽  
Linge Wang ◽  
Lea Messager ◽  
Jens Gaitzsch ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Chain Entanglement ◽  
Bottom Up ◽  
New Approach ◽  
High Genus ◽  
Transmission Electron ◽  
Minimal Radius ◽  
Stop Flow

<div><div><div><p>We report the design of polymersomes using a bottom-up approach where the self-assembly of amphiphilic copolymers poly(2-(methacryloyloxy) ethyl phosphorylcholine)–poly(2-(diisopropylamino) ethyl methacrylate) (PMPC-PDPA) into membranes is tuned using pH and temperature. We study this process in detail using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and stop-flow ab- sorbance disclosing the molecular and supramolecular anatomy of each structure observed. We report a clear evolution from disk micelles to vesicle to high-genus vesicles where each passage is controlled by pH switch or temperature. We show that the process can be rationalised adapting membrane physics theories disclosing important scaling principles that allow the estimation of the vesiculation minimal radius as well as chain entanglement and coupling. This allows us to propose a new approach to generate nanoscale vesicles with genus from 0 to 70 which have been very elusive and difficult to control so far.</p></div></div></div>

Clathrin-Inspired Coating and Stabilization of Liposomes by DNA Self-Assembly

2019 ◽  
Author(s):  
Kevin N. Baumann ◽  
Luca Piantanida ◽  
Javier García-Nafría ◽  
Diana Sobota ◽  
Kislon Voïtchovsky ◽  
...  
Keyword(s):  
Self Assembly ◽  
Mechanical Stability ◽  
Lipid Vesicles ◽  
The Self ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cryo Electron Microscopy ◽  
Further Development ◽  
Liposome Surface ◽  
Dna Coating

The self-assembly of the protein clathrin on biological membranes facilitates essential processes of endocytosis in biological systems and has provided a source of inspiration for materials design by the highly ordered structural appearance. By mimicking the architecture of clathrin self-assemblies to coat liposomes with biomaterials, new classes of hybrid carriers can be derived. Here we present a method for fabricating DNA-coated liposomes by hydrophobically anchoring and subsequently growing a DNA network on the liposome surface which structurally mimics clathrin assemblies. Dynamic light scattering (DLS), ζ-potential and cryo-electron microscopy (cryo-EM) measurements independently demonstrate successful DNA coating. Nanomechanical measurements conducted with atomic force microscopy (AFM) show that the DNA coating enhances the mechanical stability of the liposomes relative to uncoated ones. Furthermore, we provide the possibility to reverse the coating process by triggering the disassembly of the DNA coating through a toehold-mediated displacement reaction. Our results describe a straightforward, versatile, and reversible approach for coating and stabilizing lipid vesicles by an interlaced DNA network. This method has potential for further development towards the ordered arrangement of tailored functionalities on the surfaces of liposomes and for applications as hybrid nanocarrier.

Sign in / Sign up

Export Citation Format

Share Document