Crystal structure and self-assembly on graphite of a pyrazolo[1,5-c]pyrimidine derivative

2021 ◽  
Vol 77 (12) ◽  
Author(s):  
Laxmikant Trivedi ◽  
Kratika Gupta ◽  
Vipin Mishra ◽  
Thiruvancheril G. Gopakumar ◽  
Atul Gupta ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Self Assembly ◽  
Noncovalent Interactions ◽  
Pyrimidine Derivative ◽  
Monoclinic Space Group ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hydrogen Bonding Interactions ◽  
Packing Arrangement ◽  
Low Coverage

The crystal structure of the heterocyclic compound 2-(4-methoxyphenyl)-7-phenylpyrazolo[1,5-c]pyrimidine, C19H15N3O, has been determined and its self-assembly on the surface of graphite has been examined using atomic force microscopy (AFM). The title compound crystallized in the monoclinic space group P21/c, with two independent molecules in the asymmetric unit. The packing of the L-shaped molecules in the crystal is governed by arene interactions, in the absence of any conventional hydrogen-bonding interactions. The packing arrangement reveals four types of dimeric motifs stabilized by π–π and C—H...π interactions. At low coverage, molecules assemble into long needle-like islands on the graphite surface. High-resolution AFM images reveal that the molecules interact through weak noncovalent interactions between the aromatic H atoms and the methoxy O atoms.

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.

scholarly journals Morphometric characterization of fibrinogen's αC regions and their role in fibrin self-assembly and molecular organization

Nanoscale ◽  
2017 ◽  
Vol 9 (36) ◽  
pp. 13707-13716 ◽  
Author(s):  
Anna D. Protopopova ◽  
Rustem I. Litvinov ◽  
Dennis K. Galanakis ◽  
Chandrasekaran Nagaswami ◽  
Nikolay A. Barinov ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Molecular Organization ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Atomic Force Microscopy Imaging ◽  
Morphometric Characterization

High-resolution atomic force microscopy imaging reveals the role of fibrinogen αC regions in the early stages of fibrin self-assembly.

Self-assembly layer-by-layer fabrication using porphyrin dye anion and polycation

2009 ◽  
Vol 13 (07) ◽  
pp. 774-778 ◽  
Author(s):  
Byung-Soon Kim ◽  
Young-A Son
Keyword(s):  
Ultrathin Films ◽  
Self Assembly ◽  
Film Surface ◽  
Layer By Layer ◽  
Preparation Technique ◽  
Force Microscopy ◽  
Atomic Force ◽  
Diallyldimethylammonium Chloride ◽  
Afm Analysis ◽  
Progressive Growth

In this study, self-assembled alternating film using poly(diallyldimethylammonium chloride) (PDDAC) and meso-tetrakis(4-carboxyphenyl)porphyrin (MTCP) was prepared as a multilayer deposition on glass substrate. This preparation technique for dye deposition may provide new feasibilities to achieve the manufacture of ultrathin films for nanotechnology application. The deposition films were characterized by UV-vis spectrophotometer and Atomic Force Microscopy (AFM) analysis. The results of UV-vis spectra showed that the absorbance characteristic of the multilayer films linearly increased with an increased number of PDDAC and MTCP bilayers. AFM analysis showed the film surface was relatively uniform and the progressive growth of layers was determined.

scholarly journals Crystal structure and Hirshfeld surface analysis of 2-{[(4-iodophenyl)imino]methyl}-4-nitrophenol

2020 ◽  
Vol 76 (7) ◽  
pp. 1146-1149
Author(s):  
Md. Serajul Haque Faizi ◽  
Tenzile Alagöz ◽  
Ruby Ahmed ◽  
Emine Berrin Cinar ◽  
Erbil Agar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Surface Analysis ◽  
Condensation Reaction ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Orthorhombic Space Group ◽  
Compound C ◽  
Hydrogen Bonding Interactions ◽  
Packing Arrangement ◽  
Phenol Ring

The title compound, C13H9IN2O3, was synthesized by a condensation reaction between 2-hydroxy-5-nitrobenzaldehyde and 4-iodoaniline, and crystallizes in the orthorhombic space group Pna21. The 4-iodobenzene ring is inclined to the phenol ring by a dihedral angle of 39.1 (2)°. The configuration about the C=N double bond is E. The crystal structure features C—H...O hydrogen-bonding interactions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the packing arrangement are O...H/H...O (26.9%) and H...H (22.0%) interactions.

scholarly journals Recent Progress in Hydrogen-Bonded π-Conjugated Systems Displaying J-Type Aggregates

2020 ◽  
Vol 02 (01) ◽  
pp. 047-063 ◽  
Author(s):  
Nelson Ricardo Ávila-Rovelo ◽  
Amparo Ruiz-Carretero
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Noncovalent Interactions ◽  
Functional Materials ◽  
Organic Electronic Devices ◽  
Conjugated Systems ◽  
Hydrogen Bonding Interactions ◽  
Different Types ◽  
J Aggregates ◽  
Additional Hydrogen

Supramolecular approaches are of great interest in the design of functional materials. The types of aggregates arising from different noncovalent interactions endow materials with intriguing properties. In this sense, J-type aggregates are very attractive due to their unique optical properties and capacity to transport excitons. These features make them great candidates in the design of materials for organic electronic devices. Furthermore, the incorporation of additional hydrogen-bonding functionalities provides J-aggregates with superior directionality and connection among the different π-conjugated cores. The control over the formation of H-bonds to achieve functional aggregates is therefore a promising strategy towards controlled structures with specific functions.This review outlines the most relevant and recent works of π-conjugated systems exhibiting J-type aggregates resulting from hydrogen-bonding interactions. Different types of hydrogen-bonding functionalities will be discussed together with their roles in the aggregate properties, their impact in the optoelectronic properties, the self-assembly mechanisms, and their applications in organic electronics.

scholarly journals Electric Field Assisted Self-Assembly of Viruses into Colored Thin Films

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1310 ◽  
Author(s):  
James J. Tronolone ◽  
Michael Orrill ◽  
Wonbin Song ◽  
Hyun Soo Kim ◽  
Byung Yang Lee ◽  
...  
Keyword(s):  
Electric Field ◽  
Self Assembly ◽  
Force Microscopy ◽  
Thin Film Coatings ◽  
Atomic Force ◽  
Three Phase ◽  
Constant Rate ◽  
Alignment Technique ◽  
Manufacturing Techniques ◽  
Blue Line

Filamentous viruses called M13 bacteriophages are promising materials for devices with thin film coatings because phages are functionalizable, and they can self-assemble into smectic helicoidal nanofilament structures. However, the existing “pulling” approach to align the nanofilaments is slow and limits potential commercialization of this technology. This study uses an applied electric field to rapidly align the nanostructures in a fixed droplet. The electric field reduces pinning of the three-phase contact line, allowing it to recede at a constant rate. Atomic force microscopy reveals that the resulting aligned structures resemble those produced via the pulling method. The field-assisted alignment results in concentric color bands quantified with image analysis of red, green, and blue line profiles. The alignment technique shown here could reduce self-assembly time from hours to minutes and lend itself to scalable manufacturing techniques such as inkjet printing.

Effect of Sputtering Power on Structural and Optical Properties of AlN Thin Film Deposited by Reactive DC Sputtering Technique

2013 ◽  
Vol 770 ◽  
pp. 177-180 ◽  
Author(s):  
Nirun Witit-Anun ◽  
Jakrapong Kaewkhao ◽  
Surasing Chaiyakun
Keyword(s):  
Crystal Structure ◽  
Grazing Incidence ◽  
Optical Transmittance ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sputtering Power ◽  
Envelope Method ◽  
Deposited Films ◽  
Si Wafer

Aluminum nitride (AlN) thin films have been deposited on the glass slide and Si-wafer by reactive DC magnetron sputtering technique at different sputtering power. The as-deposited films have been characterized by grazing-incidence X-ray diffraction (GIXRD), atomic force microscopy (AFM) and optical transmittance, respectively. The results show that the as-deposited films were transparent and have high transmittance in visible regions. The crystal structure from XRD results show that the as-deposited films are amorphous with low sputtering power and turn to crystal structure with high sputtering power, which showed orientation of AlN structure corresponding to the AlN(1 0 0), AlN(1 0 1) and AlN(1 1 0). The roughness values and the films thickness from AFM was varied from 0.4 nm to 3.9 nm and 199 nm to 905 nm, respectively. The optical constants namely the refractive index n and the extinction coefficient k, were determined from transmittance spectrum in the visible regions by using envelope method. For 500 nm, n and k, were in the range of 1.8 2.0 and 0.014 0.004 respectively.

The Specific Binding between Galactose Group and Ricinus Communis Agglutinin (RCA) Investigated with Microcantilever

2012 ◽  
Vol 531-532 ◽  
pp. 600-604
Author(s):  
Hui Yong Zhang ◽  
Ji Hu ◽  
Hui Min Liu
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Control Experiment ◽  
Ricinus Communis ◽  
Specific Binding ◽  
Specific Interaction ◽  
Protein Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ricinus Communis Agglutinin

The specific recognization between galactose group and Ricinus Communis Agglutinin (RCA) was investigated by microcantilever. The gold side of the microcantilever was covalently bound with N-galactose, RCA and asialofetuin (ASF) via mixed self assembly monolayer of 11-mercaptoundecanoic acid and 6-mercaptohexanol, respectively. After adding RCA into the flowing cell, the deflection could be observed on the N-galactose or ASF modified microcantilever. Meanwhile, the deflection could also be observed after ASF bound to the RCA modified microcantilever. In order to prove that the deflection is caused by the specific interaction between the galactose group and RCA, bovine serum albumin (BSA) was introduced into the flowing cell as control experiment and no obvious deflection was observed. The specific interaction was also confirmed by the evidence that the bound protein layer can be mechanically removed with atomic force microscopy nanolithography technology.

scholarly journals Identification and nanomechanical characterization of the fundamental single-strand protofilaments of amyloid α-synuclein fibrils

2018 ◽  
Vol 115 (28) ◽  
pp. 7230-7235 ◽  
Author(s):  
Francesco Simone Ruggeri ◽  
Fabrizio Benedetti ◽  
Tuomas P. J. Knowles ◽  
Hilal A. Lashuel ◽  
Sergey Sekatskii ◽  
...  
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Amyloid Fibrils ◽  
Molecular Assembly ◽  
Single Strand ◽  
Force Microscopy ◽  
Atomic Force ◽  
Presynaptic Protein ◽  
Polypeptide Chains

The formation and spreading of amyloid aggregates from the presynaptic protein α-synuclein in the brain play central roles in the pathogenesis of Parkinson’s disease. Here, we use high-resolution atomic force microscopy to investigate the early oligomerization events of α-synuclein with single monomer angstrom resolution. We identify, visualize, and characterize directly the smallest elementary unit in the hierarchical assembly of amyloid fibrils, termed here single-strand protofilaments. We show that protofilaments form from the direct molecular assembly of unfolded monomeric α-synuclein polypeptide chains. To unravel protofilaments’ internal structure and elastic properties, we manipulated nanomechanically these species by atomic force spectroscopy. The single-molecule scale identification and characterization of the fundamental unit of amyloid assemblies provide insights into early events underlying their formation and shed light on opportunities for therapeutic intervention at the early stages of aberrant protein self-assembly.

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