scholarly journals Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

2018 ◽  
Vol 14 ◽  
pp. 1704-1722 ◽  
Author(s):  
Cristina Morar ◽  
Pedro Lameiras ◽  
Attila Bende ◽  
Gabriel Katona ◽  
Emese Gál ◽  
...  
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Tem Analysis ◽  
Design Synthesis ◽  
Perylene Bisimide ◽  
Self Assembling ◽  
Chemoselective Synthesis ◽  
Azobenzene Mesogens ◽  
Vt Nmr ◽  
Peripheral Unit

Background: 4-(n-Octyloxy)aniline is a known component in the elaboration of organic materials with mesogenic properties such as N-substituted Schiff bases, perylene bisimide assemblies with a number of 2-amino-4,6-bis[4-(n-octyloxy)phenylamino]-s-triazines, amphiphilic azobenzene-containing linear-dendritic block copolymers and G-0 monomeric or dimeric dendritic liquid crystals with photochromic azobenzene mesogens. The present ab initio study explores a previously unknown use of 4-(n-octyloxy)aniline in the synthesis, structure and supramolecular behaviour of new dendritic melamines. Results: Starting from 4-(n-octyloxy)aniline, seven G-2 melamine-based dendrimers were obtained in 29–79% overall yields. Their iterative convergent- and chemoselective synthesis consisted of SN2-Ar aminations of cyanuric chloride and final triple N-acylations and Williamson etherifications (→ G-2 covalent trimers) or stoichiometric carboxyl/amino 1:3 neutralisations (→ G-2 ionic trimers). These transformations connected G-1 chloro- and amino-termini dendrons to m-trivalent cores (triazin-2,4,6-triyl and benzene-1,3,5-triyl units) or tripodands (central building blocks), such as N-substituted melamines with 4-hydroxyphenyl or phenyl-4-oxyalkanoic motifs. Owing to the diversity of cores and central building blocks, the structural assortment of the dendritic series was disclosed by solvation effects (affecting reactivity), rotational stereodynamism and self-organisation phenomena (determining a vaulted and/or propeller macromolecular shape in solution). DFT calculations (in solution), (VT) NMR and IR (KBr) spectroscopy supported these assignments. TEM analysis revealed the ability of the title compounds towards self-assembling into homogeneously packed spherical nano-aggregates. Conclusions: The (non)covalent synthesis and step-by-step structural elucidation of novel G-2 melamine dendrimers based on 4-(n-octyloxy)aniline are reported. Our study demonstrates the crucial influence of the nature (covalent vs ionic) of the dendritic construction in tandem with that of its central building blocks on the aptitude of dendrimers to self-organise in solution and to self-assembly in the solid state.

scholarly journals Biocatalysis of d,l-Peptide Nanofibrillar Hydrogel

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2995 ◽  
Author(s):  
Tiziano Carlomagno ◽  
Maria C. Cringoli ◽  
Slavko Kralj ◽  
Marina Kurbasic ◽  
Paolo Fornasiero ◽  
...  
Keyword(s):  
Self Assembly ◽  
Solid Phase ◽  
Building Blocks ◽  
Cd Spectroscopy ◽  
Tem Analysis ◽  
Design Rules ◽  
Self Assembling ◽  
Transmission Electron ◽  
Oscillatory Rheometry ◽  
The Many

Self-assembling peptides are attracting wide interest as biodegradable building blocks to achieve functional nanomaterials that do not persist in the environment. Amongst the many applications, biocatalysis is gaining momentum, although a clear structure-to-activity relationship is still lacking. This work applied emerging design rules to the heterochiral octapeptide sequence His–Leu–DLeu–Ile–His–Leu–DLeu–Ile for self-assembly into nanofibrils that, at higher concentration, give rise to a supramolecular hydrogel for the mimicry of esterase-like activity. The peptide was synthesized by solid-phase and purified by HPLC, while its identity was confirmed by 1H-NMR and electrospray ionization (ESI)-MS. The hydrogel formed by this peptide was studied with oscillatory rheometry, and the supramolecular behavior of the peptide was investigated with transmission electron microscopy (TEM) analysis, circular dichroism (CD) spectroscopy, thioflavin T amyloid fluorescence assay, and attenuated total reflectance (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The biocatalytic activity was studied by monitoring the hydrolysis of p-nitrophenyl acetate (pNPA) at neutral pH, and the reaction kinetics followed an apparent Michaelis–Menten model, for which a Lineweaver–Burk plot was produced to determine its enzymatic parameters for a comparison with the literature. Finally, LC–MS analysis was conducted on a series of experiments to evaluate the extent of, if any, undesired peptide acetylation at the N-terminus. In conclusion, we provide new insights that allow gaining a clearer picture of self-assembling peptide design rules for biocatalysis.

Factors Affecting Molecular Self-Assembly and Its Mechanism

2012 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Hueyling Tan
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Polymer Science ◽  
New Approach ◽  
Factors Affecting ◽  
Dna Structures ◽  
Self Assembling ◽  
Wide Range

Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use ofpeptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study ofbiological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries ofexisting disciplines. Many self-assembling systems are rangefrom bi- andtri-block copolymers to DNA structures as well as simple and complex proteins andpeptides. The ultimate goal is to harness molecular self-assembly such that design andcontrol ofbottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes oflife and non-life science applications. Such aspirations can be achievedthrough understanding thefundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.

scholarly journals Classification of self-assembling protein nanoparticle architectures for applications in vaccine design

2017 ◽  
Vol 4 (4) ◽  
pp. 161092 ◽  
Author(s):  
G. Indelicato ◽  
P. Burkhard ◽  
R. Twarock
Keyword(s):  
Self Assembly ◽  
Vaccine Design ◽  
Building Blocks ◽  
Coiled Coils ◽  
Specific Class ◽  
Regular Graphs ◽  
Humoral Immune ◽  
Self Assembling ◽  
Display Systems

We introduce here a mathematical procedure for the structural classification of a specific class of self-assembling protein nanoparticles (SAPNs) that are used as a platform for repetitive antigen display systems. These SAPNs have distinctive geometries as a consequence of the fact that their peptide building blocks are formed from two linked coiled coils that are designed to assemble into trimeric and pentameric clusters. This allows a mathematical description of particle architectures in terms of bipartite (3,5)-regular graphs. Exploiting the relation with fullerene graphs, we provide a complete atlas of SAPN morphologies. The classification enables a detailed understanding of the spectrum of possible particle geometries that can arise in the self-assembly process. Moreover, it provides a toolkit for a systematic exploitation of SAPNs in bioengineering in the context of vaccine design, predicting the density of B-cell epitopes on the SAPN surface, which is critical for a strong humoral immune response.

scholarly journals Free-standing supramolecular hydrogel objects by reaction-diffusion

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Matija Lovrak ◽  
Wouter E. J. Hendriksen ◽  
Chandan Maity ◽  
Serhii Mytnyk ◽  
Volkert van Steijn ◽  
...  
Keyword(s):  
Structure Formation ◽  
Self Assembly ◽  
Reaction Diffusion ◽  
Building Blocks ◽  
Assembly Process ◽  
Supramolecular Hydrogel ◽  
Free Standing ◽  
Spatial Control ◽  
Self Assembling ◽  
Vast Range

Abstract Self-assembly provides access to a variety of molecular materials, yet spatial control over structure formation remains difficult to achieve. Here we show how reaction–diffusion (RD) can be coupled to a molecular self-assembly process to generate macroscopic free-standing objects with control over shape, size, and functionality. In RD, two or more reactants diffuse from different positions to give rise to spatially defined structures on reaction. We demonstrate that RD can be used to locally control formation and self-assembly of hydrazone molecular gelators from their non-assembling precursors, leading to soft, free-standing hydrogel objects with sizes ranging from several hundred micrometres up to centimeters. Different chemical functionalities and gradients can easily be integrated in the hydrogel objects by using different reactants. Our methodology, together with the vast range of organic reactions and self-assembling building blocks, provides a general approach towards the programmed fabrication of soft microscale objects with controlled functionality and shape.

Functional self-assembling polypeptide bionanomaterials

2012 ◽  
Vol 40 (4) ◽  
pp. 629-634 ◽  
Author(s):  
Tibor Doles ◽  
Sabina Božič ◽  
Helena Gradišar ◽  
Roman Jerala
Keyword(s):  
Self Assembly ◽  
Biological Systems ◽  
Three Dimensional ◽  
Coiled Coil ◽  
Chemical Properties ◽  
Building Blocks ◽  
External Signal ◽  
Form Complex ◽  
Cell Factories ◽  
Self Assembling

Bionanotechnology seeks to modify and design new biopolymers and their applications and uses biological systems as cell factories for the production of nanomaterials. Molecular self-assembly as the main organizing principle of biological systems is also the driving force for the assembly of artificial bionanomaterials. Protein domains and peptides are particularly attractive as building blocks because of their ability to form complex three-dimensional assemblies from a combination of at least two oligomerization domains that have the oligomerization state of at least two and three respectively. In the present paper, we review the application of polypeptide-based material for the formation of material with nanometre-scale pores that can be used for the separation. Use of antiparallel coiled-coil dimerization domains introduces the possibility of modulation of pore size and chemical properties. Assembly or disassembly of bionanomaterials can be regulated by an external signal as demonstrated by the coumermycin-induced dimerization of the gyrase B domain which triggers the formation of polypeptide assembly.

Symmetrical Tris(4,6-diamino-5-methylene-2-pyrimidones): New Building Blocks for Self-Assembly of Hollow Spherical Supramolecules Locked by Hydrogen Bonds

1996 ◽  
Vol 61 (10) ◽  
pp. 1464-1472 ◽  
Author(s):  
Daniel Alexander ◽  
Petr Holý ◽  
Pavel Fiedler ◽  
Zdeněk Havlas ◽  
Jiří Závada
Keyword(s):  
Molecular Modeling ◽  
Hydrogen Bonds ◽  
Gas Phase ◽  
Self Assembly ◽  
Building Blocks ◽  
The Self ◽  
Circumstantial Evidence ◽  
Self Assembling ◽  
Molecular Modeling Study ◽  
Modeling Study

Concise synthesis of the tris(pyrimidones) 1a,b is described. Molecular modeling study demonstrated that both the prepared models 1a,b are capable of self-assembling under formation of spherical dimers locked by 18 hydrogen bonds. Extreme insolubility in all common solvents precluded investigation of the self-assembly in solution. Circumstantial evidence in favor of the self-assembly has been provided in the solid and gas phase.

Capillary And Magnetic Forces For Microscale Self-Assembled Systems

2010 ◽  
Vol 1272 ◽  
Author(s):  
Christopher J. Morris ◽  
Kate E. Laflin ◽  
Brian Isaacson ◽  
Michael Grapes ◽  
David Gracias
Keyword(s):  
Melting Point ◽  
Solder Alloy ◽  
Self Assembly ◽  
Permanent Magnets ◽  
Building Blocks ◽  
Capillary Forces ◽  
Silicon Chips ◽  
Magnetic Forces ◽  
Fundamental Limitations ◽  
Self Assembling

AbstractSelf-assembly is a promising technique to overcome fundamental limitations with integrating, packaging, and generally handling individual electronic-related components with characteristic lengths significantly smaller than 1 mm. Here we briefly summarize the use of capillary and magnetic forces to realize two example microscale systems. In the first example, we use capillary forces from a low melting point solder alloy to integrate 500 μm square, 100 μm thick silicon chips with thermally and chemically sensitive metal-polymer hinge actuators, for potential medical applications. The second example demonstrates a path towards self-assembling 3-D silicon circuits formed out of 280 μm sized building blocks, utilizing both capillary forces from a low melting point solder alloy and magnetic forces from integrated, permanent magnets. In the latter example, the utilization of magnetic forces combined with capillary forces improved the assembly yield to 7.8% over 0.1% achieved previously with capillary forces alone.

Self-Assembly Processes for Organic Led Transport Layers and Electrode Passivation

1999 ◽  
Vol 558 ◽  
Author(s):  
J.E. Malinsky ◽  
W. Li ◽  
Q. Wang ◽  
J. Cui ◽  
H. Chou ◽  
...  
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Hole Transport ◽  
Transport Layer ◽  
Dielectric Films ◽  
Hole Transport Layer ◽  
Use Of Self ◽  
Self Assembling ◽  
Electrode Passivation ◽  
Thin Dielectric Films

ABSTRACTThis contribution describes the use of self-limiting siloxane chemisoroption processes to self-assemble building blocks for the modification of vacuum-deposited organic LED (OLED) devices. One approach consists of the use of self-assembling OLED hole transport materials for application in hybrid self-assembled + vapor deposited two-layer devices. Another approach involves the application of self-limiting, chemisorptive self-assembly techniques to introduce thin dielectric films between the anode and hole transport layer of a vapor deposited two-layer OLED device.

scholarly journals Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6786
Author(s):  
Gulnara Gaynanova ◽  
Leysan Vasileva ◽  
Ruslan Kashapov ◽  
Darya Kuznetsova ◽  
Rushana Kushnazarova ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Self Assembly ◽  
Targeted Delivery ◽  
Building Blocks ◽  
Biological Barriers ◽  
Self Assembling ◽  
Low Toxicity ◽  
Natural Building ◽  
Dynamic Structures ◽  
Supramolecular Aggregates

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.

scholarly journals The Human LL-37(17-29) Antimicrobial Peptide Reveals a Functional Supramolecular Nanostructure

2020 ◽  
Author(s):  
Yizhaq Engelberg ◽  
Meytal Landau
Keyword(s):  
Lipid Bilayers ◽  
Self Assembly ◽  
Amyloid Fibrils ◽  
Biological Activities ◽  
Building Blocks ◽  
Bacterial Cells ◽  
Bacterial Membranes ◽  
Self Assembling ◽  
Wide Ribbon ◽  
Wide Range

Protein fibrils that perform biological activities present attractive biomaterials. Here we demonstrate, by crystal structures, the self-assembly of the antibacterial human LL-37 active core (residues 17-29) into a stable structure of densely packed helices. The surface of the fibril encompasses alternating hydrophobic and positively charged zigzagged belts, which likely underlie interactions with and subsequent disruption of negatively charged lipid bilayers, such as bacterial membranes. LL-3717-29 correspondingly formed wide, ribbon-like, thermostable fibrils in solution, which co-localized with bacterial cells, and structure-guided mutagenesis analyses supported the role of self-assembly in antibacterial activity. LL-3717-29 resembled, in sequence and in the ability to form amphipathic helical fibrils, the bacterial cytotoxic PSMα3 peptide that assembles into cross-α amyloid fibrils. This suggests helical, self-assembling, basic building blocks across kingdoms of life and point to potential structural mimicry mechanisms. The findings offer a scaffold for functional and durable nanostructures for a wide range of medical and technological applications.

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