scholarly journals Deciphering Multiple Critical Parameters of Polymeric Self-Assembly by Fluorescence Spectroscopy of a Single Molecular Rotor BODIPY-C12

2021 ◽  
Author(s):  
Ekaterina Lisitsyna ◽  
Alexander Efimov ◽  
Clémentine Depresle ◽  
Pierre Cauchois ◽  
Elina Vuorimaa-Laukkanen ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Self Assembly ◽  
Critical Parameters ◽  
Molecular Rotor

scholarly journals Probing the self-assembly dynamics and internal structure of amphiphilic hyaluronic acid conjugates by fluorescence spectroscopy and molecular dynamics simulations

Soft Matter ◽  
2018 ◽  
Vol 14 (23) ◽  
pp. 4762-4771 ◽  
Author(s):  
Denis Svechkarev ◽  
Alexander Kyrychenko ◽  
William M. Payne ◽  
Aaron M. Mohs
Keyword(s):  
Molecular Dynamics ◽  
Hyaluronic Acid ◽  
Fluorescence Spectroscopy ◽  
Molecular Dynamics Simulations ◽  
Internal Structure ◽  
Self Assembly ◽  
The Self ◽  
Dynamics Simulations

Side substituents on the hyaluronic acid backbone determine the morphology and hydration of the HA-derived nanoparticles hydrophobic domains.

Morphology Controlled Nanostructure of Zinc Porphyrin

2013 ◽  
Vol 562-565 ◽  
pp. 1314-1318
Author(s):  
Jun Jie Li ◽  
Chang Jun Hou ◽  
Zhi Fei Li ◽  
Huan Bao Fa ◽  
Mei Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Fluorescence Spectroscopy ◽  
Aqueous Solutions ◽  
Self Assembly ◽  
Cationic Surfactants ◽  
Zinc Porphyrin ◽  
Assembly Method ◽  
Fluorescent Spectra ◽  
Anionic And Cationic Surfactants ◽  
Surfactant Assisted

We have shown that various Zinc porphyrin-based nanostructures can be easily synthesized by a surfactant-assisted self-assembly method, where nonionic, anionic and cationic surfactants are employed. It was found that tuning the type of surfactant offered an alternative to promote the formation of Zinc porphyrin nanostructure with different morphologies in aqueous solutions. As-prepared nano-scale self-assemblies, including disc-shaped, ellipsoid, square and quadrangular pyramidal nanoparticles, were investigated in solution via UV/vis, fluorescence spectroscopy and SEM microscopy. The different UV/vis as well as fluorescent spectra between nano-porphyrin and its monomer further conformed that the nano-crystallization of porphyrin would result in novel optical properties differing from the single subunits.

scholarly journals Impact of Line Edge Roughness on ReRAM Uniformity and Scaling

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3972
Author(s):  
Vassilios Constantoudis ◽  
George Papavieros ◽  
Panagiotis Karakolis ◽  
Ali Khiat ◽  
Themistoklis Prodromakis ◽  
...  
Keyword(s):  
Self Assembly ◽  
Random Access ◽  
Resistive Random Access Memory ◽  
Critical Parameters ◽  
Theoretical Formula ◽  
Line Edge Roughness ◽  
Access Memory ◽  
Cross Point ◽  
Point Patterns ◽  
Edge Roughness

We investigate the effects of Line Edge Roughness (LER) of electrode lines on the uniformity of Resistive Random Access Memory (ReRAM) device areas in cross-point architectures. To this end, a modeling approach is implemented based on the generation of 2D cross-point patterns with predefined and controlled LER and pattern parameters. The aim is to evaluate the significance of LER in the variability of device areas and their performances and to pinpoint the most critical parameters and conditions. It is found that conventional LER parameters may induce >10% area variability depending on pattern dimensions and cross edge/line correlations. Increased edge correlations in lines such as those that appeared in Double Patterning and Directed Self-assembly Lithography techniques lead to reduced area variability. Finally, a theoretical formula is derived to explain the numerical dependencies of the modeling method.

scholarly journals Measuring viscosity inside mesoporous silica using protein-bound molecular rotor probe

2018 ◽  
Vol 20 (36) ◽  
pp. 23202-23213 ◽  
Author(s):  
Pegah S. Nabavi Zadeh ◽  
Milene Zezzi do Valle Gomes ◽  
Maria Abrahamsson ◽  
Anders E. C. Palmqvist ◽  
Björn Åkerman
Keyword(s):  
Mesoporous Silica ◽  
Fluorescence Spectroscopy ◽  
Effective Viscosity ◽  
Molecular Rotors ◽  
Molecular Rotor

Fluorescence spectroscopy of protein-bound molecular rotors Cy3 and Cy5 is used to monitor the effective viscosity inside the pores of two types of mesoporous silica (SBA-15 and MCF) with pore diameters between 8.9 and 33 nm.

Monitoring Supramolecular Self-Assembly using Time-Resolved Fluorescence Spectroscopy

2011 ◽  
Vol 64 (6) ◽  
pp. 825 ◽  
Author(s):  
Scott C. McLean ◽  
Colin A. Scholes ◽  
Trevor A. Smith ◽  
Michelle L. Gee
Keyword(s):  
Fluorescence Spectroscopy ◽  
Self Assembly ◽  
Supramolecular Structure ◽  
Micelle Formation ◽  
Fluorescence Decay ◽  
Distribution Analysis ◽  
Time Resolved Fluorescence ◽  
Decay Kinetics ◽  
Time Resolved ◽  
Relative Population

Time-resolved fluorescence spectroscopy is used to observe subtleties in supramolecular structure during the self-assembly of polymers in solution. Lifetime distribution analysis of the fluorescence decay kinetics of the solvent-sensitive fluorescent probe 1-anilino-8-naphthalene sulfonic acid associated with the di-block copolymer poly(2-vinylpyridine)41–poly(ethylene oxide)204 (P2VP-PEO) as it self-assembles enabled identification of three microdomains, distinguishable on the basis of micropolarity. These microdomains can be assigned to different supramolecular substructures: the micelle corona (high polarity), the micelle core and the P2VP globule (both low polarity), and the core–corona interface and the globule–PEO junction (both intermediate polarity). Changes in the relative population distributions of these sub-structures as a function of P2VP-PEO pinpoint the onset of micellization corresponding to the critical micelle concentration (CMC) of the copolymer, but indicate significant variation in supramolecular structure, including micelle formation, well below the CMC. This suggests that supramolecular self-assembly in polymeric systems has characteristics of a second order phase transition.

scholarly journals Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals

2017 ◽  
Vol 114 (11) ◽  
pp. 2836-2841 ◽  
Author(s):  
X. Wendy Gu ◽  
Xingchen Ye ◽  
David M. Koshy ◽  
Shraddha Vachhani ◽  
Peter Hosemann ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Self Assembly ◽  
Structural Disorder ◽  
Structural Features ◽  
Structural Defects ◽  
Critical Parameters ◽  
Recent Developments ◽  
Self Assembled ◽  
Elastic And Plastic Deformation

Large, freestanding membranes with remarkably high elastic modulus (>10 GPa) have been fabricated through the self-assembly of ligand-stabilized inorganic nanocrystals, even though these nanocrystals are connected only by soft organic ligands (e.g., dodecanethiol or DNA) that are not cross-linked or entangled. Recent developments in the synthesis of polymer-grafted nanocrystals have greatly expanded the library of accessible superlattice architectures, which allows superlattice mechanical behavior to be linked to specific structural features. Here, colloidal self-assembly is used to organize polystyrene-grafted Au nanocrystals at a fluid interface to form ordered solids with sub-10-nm periodic features. Thin-film buckling and nanoindentation are used to evaluate the mechanical behavior of polymer-grafted nanocrystal superlattices while exploring the role of polymer structural conformation, nanocrystal packing, and superlattice dimensions. Superlattices containing 3–20 vol % Au are found to have an elastic modulus of ∼6–19 GPa, and hardness of ∼120–170 MPa. We find that rapidly self-assembled superlattices have the highest elastic modulus, despite containing significant structural defects. Polymer extension, interdigitation, and grafting density are determined to be critical parameters that govern superlattice elastic and plastic deformation.

scholarly journals How fluorescent tags modify oligomer size distributions of the Alzheimer-peptide Aβ(1-40)

2018 ◽  
Author(s):  
J. Wägele ◽  
S. De Sio ◽  
B. Voigt ◽  
J. Balbach ◽  
M. Ott
Keyword(s):  
Molecular Weight ◽  
Fluorescence Spectroscopy ◽  
Single Molecule ◽  
Self Assembly ◽  
Underlying Mechanism ◽  
Fibrillar Structure ◽  
Low Molecular Weight ◽  
Size Distributions ◽  
Time Resolved ◽  
Fluorescent Tags

ABSTRACTWithin the complex aggregation process of Aβ-peptides into fibrils, oligomeric species, play a central role and reveal fundamental properties of the underlying mechanism of aggregation. In particular, low molecular weight aggregates have attracted increasing interest because of their role in cytotoxicity and neuronal apoptosis, typical of aggregation related diseases. One of the main techniques used to characterize such early stages of aggregation is fluorescence spectroscopy. To this end, Aβ-peptide chains are functionalized with fluorescent tags, often covalently bound to the disordered N-terminus region of the peptide, with the assumption that functionalization and presence of the fluorophore will not modify the process of self-assembly nor the final fibrillar structure. Up to date, experimental findings reveal size distributions of thermodynamically stable oligomers ranging from very narrow distributions of dimers to octamers, to very broad distributions up to 50-mers. In the present investigation we systematically study the effects of five of the most commonly used fluorophores on the aggregation of Aβ(1-40)-peptides. Time-resolved and single-molecule fluorescence spectroscopy have been chosen to monitor the oligomer populations at different fibrillation times, TEM, AFM and X-ray diffraction to investigate the structure of mature fibrils. While the structures of the mature fibrils were only slightly affected by the fluorescent tags, the sizes of the detected oligomeric species varied significantly depending on the chosen fluorophore. In particular, we relate the presence of high molecular weight oligomers (as found for the fluorophores HiLyte 647, Atto 647N and Atto 655) to net-attractive, hydrophobic fluorophore-peptide interactions, which are weak in the case of HiLyte 488, and Atto 488. The latter form low molecular weight oligomers only. Our findings reveal the potentially high impact of the properties of fluorophores on transient aggregates which needs to be included in the interpretation of experimental data of oligomers of fluorescently labeled peptides.

Direct monitoring of self-assembly of copolymeric micelles by a luminescent molecular rotor

2013 ◽  
Vol 49 (76) ◽  
pp. 8474 ◽  
Author(s):  
Gianfranco Vaccaro ◽  
Alberto Bianchi ◽  
Michele Mauri ◽  
Simone Bonetti ◽  
Francesco Meinardi ◽  
...  
Keyword(s):  
Self Assembly ◽  
Molecular Rotor

Self-Assembled Trigonal Prismatic Altitudinal Rotors with Triptycene Paddle Wheels

2005 ◽  
Vol 70 (11) ◽  
pp. 1970-1985 ◽  
Author(s):  
Douglas C. Caskey ◽  
Bing Wang ◽  
Xiaolai Zheng ◽  
Josef Michl
Keyword(s):  
Self Assembly ◽  
Collision Induced Dissociation ◽  
Molecular Rotor ◽  
Self Assembled ◽  
Trigonal Prismatic

We describe the synthesis of a trigonal prismatic molecular rotor by self-assembly from paddlewheel carrying molecular rods and trigonal star connectors in a 3:2 ratio. The rod is 9,10-diethynyltriptycene terminated in transversely reactive [Pt(dppp)]+ groups (dppp = 1,3-bis(diphenylphosphino)propane) and the connector is 1,3,5-tris[(4-pyridyl)ethynyl]benzene. The structure of the molecular rotor has been established by 2-D NMR and MS, including diffusion-ordered NMR and collision-induced dissociation.

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