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.

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.

Controllable Synthesis of Cobalt Porphyrin Nanocrystals through Micelle Confinement Self-Assembly

MRS Advances ◽  
2020 ◽  
Vol 5 (42) ◽  
pp. 2147-2155
Author(s):  
Sudi Chen ◽  
Xitong Ren ◽  
Shufang Tian ◽  
Jiajie Sun ◽  
Feng Bai
Keyword(s):  
Self Assembly ◽  
Water Oxidation ◽  
Separation Efficiency ◽  
Noncovalent Interactions ◽  
Building Blocks ◽  
The Self ◽  
Hexagonal Prism ◽  
Assembly Process ◽  
Surfactant Micelles ◽  
Cobalt Porphyrin

AbstractThe self-assembly of optically active building blocks into functional nanocrystals as high-activity photocatalysts is a key in the field of photocatalysis. Cobalt porphyrin with abundant catalytic properties is extensively studied in photocatalytic water oxidation and CO2 reduction. Here, we present the fabrication of cobalt porphyrin nanocrystals through a surfactant-assisted interfacial self-assembly process using Co-tetra(4-pyridyl) porphyrin as building block. The self-assembly process relies on the combined noncovalent interactions such as π-π stacking and axial Co-N coordination between individual porphyrin molecules within surfactant micelles. Tuning different reaction conditions (temperature, the ratio of co-solvent DMF) and types of surfactant, various nanocrystals with well-defined 1D to 3D morphologies such as nanowires, nanorods and nano hexagonal prism were obtained. Due to the ordered accumulation of molecules, the nanocrystals exhibit the properties of the enhanced capability of visible light capture and can conduce to improve the transport and separation efficiency of the photogenerated carriers, which is important for photocatalysis. Further studies of photocatalytic CO2 reduction are being performed to address the relationship between the size and shape of the nanocrystals with the photocatalytic activity.

scholarly journals Modification of a Single Atom Affects the Physical Properties of Double Fluorinated Fmoc-Phe Derivatives

2021 ◽  
Vol 22 (17) ◽  
pp. 9634
Author(s):  
Moran Aviv ◽  
Dana Cohen-Gerassi ◽  
Asuka A. Orr ◽  
Rajkumar Misra ◽  
Zohar A. Arnon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Physical Properties ◽  
Self Assembly ◽  
Deep Understanding ◽  
Building Blocks ◽  
The Self ◽  
Single Atom ◽  
Supramolecular Organization ◽  
Assembly Process ◽  
Wide Range

Supramolecular hydrogels formed by the self-assembly of amino-acid based gelators are receiving increasing attention from the fields of biomedicine and material science. Self-assembled systems exhibit well-ordered functional architectures and unique physicochemical properties. However, the control over the kinetics and mechanical properties of the end-products remains puzzling. A minimal alteration of the chemical environment could cause a significant impact. In this context, we report the effects of modifying the position of a single atom on the properties and kinetics of the self-assembly process. A combination of experimental and computational methods, used to investigate double-fluorinated Fmoc-Phe derivatives, Fmoc-3,4F-Phe and Fmoc-3,5F-Phe, reveals the unique effects of modifying the position of a single fluorine on the self-assembly process, and the physical properties of the product. The presence of significant physical and morphological differences between the two derivatives was verified by molecular-dynamics simulations. Analysis of the spontaneous phase-transition of both building blocks, as well as crystal X-ray diffraction to determine the molecular structure of Fmoc-3,4F-Phe, are in good agreement with known changes in the Phe fluorination pattern and highlight the effect of a single atom position on the self-assembly process. These findings prove that fluorination is an effective strategy to influence supramolecular organization on the nanoscale. Moreover, we believe that a deep understanding of the self-assembly process may provide fundamental insights that will facilitate the development of optimal amino-acid-based low-molecular-weight hydrogelators for a wide range of applications.

Evolving Reaction-Diffusion Ecosystems with Self-Assembling Structures in Thin Films

1998 ◽  
Vol 4 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Jens Breyer ◽  
Jörg Ackermann ◽  
John McCaskill
Keyword(s):  
Self Assembly ◽  
Flexible Structures ◽  
Reaction Diffusion ◽  
In Vitro Evolution ◽  
Spatially Resolved ◽  
Self Assembling ◽  
Artificial Dna ◽  
Additional Stabilization ◽  
Artificial Chemistries

Recently, new types of coupled isothermal polynucleotide amplification reactions for the investigation of in vitro evolution have been established that are based on the multi-enzyme 3SR reaction. Microstructured thin-film open bioreactors have been constructed in our laboratory to run these reactions spatially resolved in flow experiments. Artificial DNA/RNA chemistries close to the in vitro biochemistry of these systems have been developed, which we have studied in computer simulations in configurable hardware (NGEN). These artificial chemistries are described on the level of individual polynucleotide molecules, each with a defined sequence, and their complexes. The key feature of spatial pattern formation provides a weak stabilization of cooperative catalytic properties of the evolving molecules. Of great interest is the step to include extended self-assembly processes of flexible structures—allowing the additional stabilization of cooperation through semipermeable, flexible, self-organizing membrane boundaries. We show how programmable matter simulations of experimentally relevant molecular in vitro evolution can be extended to include the influence of self-assembling flexible membranes.

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 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.

scholarly journals Light-directed trapping of metastable intermediates in a self-assembly process

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Joonsik Seo ◽  
Joonyoung F. Joung ◽  
Sungnam Park ◽  
Young Ji Son ◽  
Jaegeun Noh ◽  
...  
Keyword(s):  
Self Assembly ◽  
Alkyl Chain ◽  
Perylene Diimide ◽  
Chemical Compositions ◽  
Assembly Process ◽  
Supramolecular Framework ◽  
Tubular Structures ◽  
Significant Information ◽  
Self Assembling ◽  
General Method

AbstractSelf-assembly is a dynamic process that often takes place through a stepwise pathway involving formation of kinetically favored metastable intermediates prior to generation of a thermodynamically preferred supramolecular framework. Although trapping intermediates in these pathways can provide significant information about both their nature and the overall self-assembly process, it is a challenging venture without altering temperature, concentrations, chemical compositions and morphologies. Herein, we report a highly efficient and potentially general method for “trapping” metastable intermediates in self-assembly processes that is based on a photopolymerization strategy. By employing a chiral perylene-diimide possessing a diacetylene containing an alkyl chain, we demonstrated that the metastable intermediates, including nanoribbons, nanocoils and nanohelices, can be effectively trapped by using UV promoted polymerization before they form thermodynamic tubular structures. The strategy developed in this study should be applicable to naturally and synthetically abundant alkyl chain containing self-assembling systems.

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.

Self-Assembling Microspheres from Charged Functional Polyelectrolytes and Small-Molecule Counterions

2004 ◽  
Vol 823 ◽  
Author(s):  
Brandon Mckenna ◽  
Henrik Birkedal ◽  
Michael H. Bartl ◽  
Timothy J. Deming ◽  
Galen D. Stucky
Keyword(s):  
Amino Acids ◽  
Confocal Microscopy ◽  
Self Assembly ◽  
Fluorescent Labeling ◽  
Vesicle Formation ◽  
Assembly Process ◽  
Covalent Crosslinking ◽  
Self Assembling ◽  
Minimum Number ◽  
Sphere Formation

AbstractMicrometer-sized spheres have been found to assemble from homopolymer electrolytes and small, multivalent counterions in water. In contrast to previous efforts, these vesicles do not use preformed templates, do not require block copolymers, and do not necessarily employ nanoparticles. We have investigated the requirements for vesicle formation with regards to both components of the assembly. Self-assembly occurs with a variety of poly-amino acids and counterions, all of which require a minimum number of charged groups to promote non-covalent crosslinking. We show how the assembly process is controlled by pH and how, in consequence, the pKa's of the reactants can be used to reliably predict sphere formation. By varying the nature of the small counterions, we have determined the requirements for assemblies. The assemblies have been further investigated using confocal microscopy and fluorescent labeling of the different components.

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