Controlling stiffness in nanostructured hydrogels produced by enzymatic dephosphorylation

2009 ◽  
Vol 37 (4) ◽  
pp. 660-664 ◽  
Author(s):  
Kate Thornton ◽  
Andrew M. Smith ◽  
Catherine L.R. Merry ◽  
Rein V. Ulijn
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Gelation Time ◽  
Three Dimensional ◽  
Precursor Solution ◽  
Cost Effective ◽  
Cd Spectroscopy ◽  
Phosphate Ester ◽  
Self Assembling ◽  
Oscillatory Rheology

In the present paper, we report on enzyme-initiated self-assembly of Fmoc (fluoren-9-ylmethoxycarbonyl)–tyrosine hydrogels by enzymatic dephosphorylation under physiological conditions and provide evidence for the ability to control the modulus. Upon enzyme action, a self-assembling network of interconnecting fibres is formed, observed by cryo-SEM (scanning electron microscopy) and TEM (transmission electron microscopy). The concentration of alkaline phosphatase added to the Fmoc–tyrosine phosphate ester precursor solution had a direct effect on the gelation time, mechanical properties and molecular arrangements as determined through oscillatory rheology, fluorescence spectroscopy and CD spectroscopy. This highly tuneable cost-effective gel system may have applications in three-dimensional cell culture.

Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Light Scattering ◽  
Chain Length ◽  
Self Assembly ◽  
The Self ◽  
Ionic Charge ◽  
Self Assembling ◽  
Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

scholarly journals Layer-by-Layer Self-Assembled Ferrite Multilayer Nanofilms for Microwave Absorption

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jiwoong Heo ◽  
Daheui Choi ◽  
Jinkee Hong
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Precursor Solution ◽  
Ferrite Nanoparticles ◽  
Energy Dispersive ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Scanning Electron

We demonstrate a simple method for fabricating multilayer thin films containing ferrite (Co0.5Zn0.5Fe2O4) nanoparticles, using layer-by-layer (LbL) self-assembly. These films have microwave absorbing properties for possible radar absorbing and stealth applications. To demonstrate incorporation of inorganic ferrite nanoparticles into an electrostatic-interaction-based LbL self-assembly, we fabricated two types of films: (1) a blended three-component LbL film consisting of a sequential poly(acrylic acid)/oleic acid-ferrite blend layer and a poly(allylamine hydrochloride) layer and (2) a tetralayer LbL film consisting of sequential poly(diallyldimethylammonium chloride), poly(sodium-4-sulfonate), bPEI-ferrite, and poly(sodium-4-sulfonate) layers. We compared surface morphologies, thicknesses, and packing density of the two types of ferrite multilayer film. Ferrite nanoparticles (Co0.5Zn0.5Fe2O4) were prepared via a coprecipitation method from an aqueous precursor solution. The structure and composition of the ferrite nanoparticles were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. X-ray diffraction patterns of ferrite nanoparticles indicated a cubic spinel structure, and energy dispersive X-ray spectroscopy revealed their composition. Thickness growth and surface morphology were measured using a profilometer, atomic force microscope, and scanning electron microscope.

scholarly journals Synthetic self-assembling ADDomer platform for highly efficient vaccination by genetically encoded multiepitope display

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw2853 ◽  
Author(s):  
Charles Vragniau ◽  
Joshua C. Bufton ◽  
Frédéric Garzoni ◽  
Emilie Stermann ◽  
Fruzsina Rabi ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Electron Microscopy ◽  
High Performance ◽  
Vaccine Candidate ◽  
Cost Effective ◽  
Atomic Resolution ◽  
Self Assembling ◽  
Cryo Electron Microscopy ◽  
Architectural Features ◽  
Multimeric Protein

Self-assembling virus-like particles represent highly attractive tools for developing next-generation vaccines and protein therapeutics. We created ADDomer, an adenovirus-derived multimeric protein-based self-assembling nanoparticle scaffold engineered to facilitate plug-and-play display of multiple immunogenic epitopes from pathogens. We used cryo–electron microscopy at near-atomic resolution and implemented novel, cost-effective, high-performance cloud computing to reveal architectural features in unprecedented detail. We analyzed ADDomer interaction with components of the immune system and developed a promising first-in-kind ADDomer-based vaccine candidate to combat emerging Chikungunya infectious disease, exemplifying the potential of our approach.

scholarly journals Synthesis of Thermo-Responsive Block-Graft Copolymer Based on PCL and PEG Analogs, and Preparation of Hydrogel via Click Chemistry

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 765 ◽  
Author(s):  
Pei Shang ◽  
Jie Wu ◽  
Xiaoyu Shi ◽  
Zhidan Wang ◽  
Fei Song ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graft Copolymer ◽  
Self Assembly ◽  
Three Dimensional ◽  
Cycloaddition Reaction ◽  
Temperature Response ◽  
Gel Permeation Chromatography ◽  
Proton Nuclear Magnetic Resonance ◽  
Fluorescence Probes ◽  
Different Temperatures

Thermo-responsive cross-linkable mPEG-b-[PCL-g-(MEO2MA-co-OEGMA)]-b-mPEG was synthesized by ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Then, the cross-linkable block-graft copolymer was used to prepare hydrogel via a copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition reaction. The chemical structure and composition of copolymer were characterized by proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behaviors of the copolymer in aqueous solution were studied by UV spectrophotometer, fluorescence probes, the surface tension method, dynamic light scattering, and transmission electron microscopy. The results proved that the copolymer has excellent solubility and better temperature response. The three-dimensional network structure of the gels, observed by scanning electron microscopy at different temperatures, indicated that the gels have temperature response.

Peptide α-helices for synthetic nanostructures

2007 ◽  
Vol 35 (3) ◽  
pp. 487-491 ◽  
Author(s):  
M.G. Ryadnov
Keyword(s):  
Self Assembly ◽  
De Novo ◽  
Three Dimensional ◽  
Functional Materials ◽  
Protein Assemblies ◽  
Helical Peptides ◽  
Design Rules ◽  
Natural Protein ◽  
Self Assembling ◽  
Recent Developments

Supramolecular structures arising from a broad range of chemical archetypes are of great technological promise. Defining such structures at the nanoscale is crucial to access principally new types of functional materials for applications in bionanotechnology. In this vein, biomolecular self-assembly has emerged as an efficient approach for building synthetic nanostructures from the bottom up. The approach predominantly employs the spontaneous folding of biopolymers to monodisperse three-dimensional shapes that assemble into hierarchically defined mesoscale composites. An immediate interest here is the extraction of reliable rules that link the chemistry of biopolymers to the mechanisms of their assembly. Once established these can be further harnessed in designing supramolecular objects de novo. Different biopolymer classes compile a rich repertoire of assembly motifs to facilitate the synthesis of otherwise inaccessible nanostructures. Among those are peptide α-helices, ubiquitous folding elements of natural protein assemblies. These are particularly appealing candidates for prescriptive supramolecular engineering, as their well-established and conservative design rules give unmatched predictability and rationale. Recent developments of self-assembling systems based on helical peptides, including fibrous systems, nanoscale linkers and reactors will be highlighted herein.

Using organic solvent absorption as a self-assembly method to synthesize three-dimensional (3D) reduced graphene oxide (RGO)/poly(3,4-ethylenedioxythiophene) (PEDOT) architecture and its electromagnetic absorption properties

RSC Advances ◽  
2014 ◽  
Vol 4 (91) ◽  
pp. 49780-49782 ◽  
Author(s):  
Fan Wu ◽  
Yuan Wang ◽  
Mingyang Wang
Keyword(s):  
Organic Solvent ◽  
Self Assembly ◽  
Three Dimensional ◽  
Absorption Properties ◽  
Self Assembling ◽  
Assembly Method ◽  
Electromagnetic Absorption ◽  
Solvent Absorption ◽  
Reduced Graphene ◽  
Promising Application

A novel self-assembling 3D-RGO/PEDOT architecture has been synthesized through organic solvent absorption and gentle heating. It gives a promising application in electromagnetic absorption.

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.

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.

Solvent–Controlled Helicity in Self-Assembling Rosette Nanotubes

2006 ◽  
Vol 922 ◽  
Author(s):  
Ross S Johnson ◽  
Takeshi Yamazaki ◽  
Andriy Kovalenko ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cd Spectroscopy ◽  
Mirror Image ◽  
Supramolecular System ◽  
Rosette Nanotubes ◽  
Self Assembling ◽  
Transmission Electron ◽  
Molecular Modeling Studies ◽  
Scanning Electron

AbstractA newly designed module was synthesized and found to self-assemble into rosette nanotubes (RN) in both water and methanol. Characterization using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) established the formation of analogous RNs in both solvents. However, the chiroptical outcome of the assemblies, observed by circular dichrosim (CD) spectroscopy, was found to be mirror image based solely on the solvent used. Preliminary molecular modeling studies indicated the formation of M and P helical rosette nanotubes, in agreement with the experimental observations. This work represents the first example of solvent-controlled helicity in a self-assembling supramolecular system.

scholarly journals Simple Self-Assembly Strategy of Nanospheres on 3D Substrate and Its Application for Enhanced Textured Silicon Solar Cell

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2581
Author(s):  
Dan Su ◽  
Lei Lv ◽  
Yi Yang ◽  
Huan-Li Zhou ◽  
Sami Iqbal ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Light Trapping ◽  
Incident Light ◽  
Three Dimensional ◽  
Cost Effective ◽  
Optical Measurements ◽  
Sio2 Coating ◽  
Assembly Strategy ◽  
Cost Effective Approach

Nanomaterials and nanostructures provide new opportunities to achieve high-performance optical and optoelectronic devices. Three-dimensional (3D) surfaces commonly exist in those devices (such as light-trapping structures or intrinsic grains), and here, we propose requests for nanoscale control over nanostructures on 3D substrates. In this paper, a simple self-assembly strategy of nanospheres for 3D substrates is demonstrated, featuring controllable density (from sparse to close-packed) and controllable layer (from a monolayer to multi-layers). Taking the assembly of wavelength-scale SiO2 nanospheres as an example, it has been found that textured 3D substrate promotes close-packed SiO2 spheres compared to the planar substrate. Distribution density and layers of SiO2 coating can be well controlled by tuning the assembly time and repeating the assembly process. With such a versatile strategy, the enhancement effects of SiO2 coating on textured silicon solar cells were systematically examined by varying assembly conditions. It was found that the close-packed SiO2 monolayer yielded a maximum relative efficiency enhancement of 9.35%. Combining simulation and macro/micro optical measurements, we attributed the enhancement to the nanosphere-induced concentration and anti-reflection of incident light. The proposed self-assembly strategy provides a facile and cost-effective approach for engineering nanomaterials at 3D interfaces.

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