pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

Peptide-based biopolymers represent highly promising biocompatible materials with multiple applications, such as tailored drug delivery, tissue engineering and regeneration, and as stimuli-responsive materials. Herein, we report the pH- and concentration-dependent self-assembly and conformational transformation of the newly synthesized octapeptide PEP-1. At pH 7.4, PEP-1 forms β-sheet-rich secondary structures into fractal-like morphologies, as verified by circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, thioflavin T (ThT) fluorescence spectroscopy assay, and atomic force microscopy (AFM). Upon changing the pH value (using pH 5.5 and 13.0), PEP-1 forms different types of secondary structures and resulting morphologies due to electrostatic repulsion between charged amino acids. PEP-1 can also form helical or random-coil secondary structures at a relatively low concentration. The obtained pH-sensitive self-assembly behavior of the target octapeptide is expected to contribute to the development of novel drug nanocarrier assemblies.

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Synthesis and self-assembly of photoacid-containing block copolymers based on 1-naphthol

Polymer Chemistry ◽

10.1039/c9py01131e ◽

2019 ◽

Vol 10 (41) ◽

pp. 5602-5616 ◽

Cited By ~ 5

Author(s):

Felix Wendler ◽

Jessica C. Tom ◽

Felix H. Schacher

Keyword(s):

Block Copolymers ◽

Self Assembly ◽

Molecular Switches ◽

Amphiphilic Block Copolymers ◽

Strong Increase ◽

Stimuli Responsive ◽

Responsive Materials

Photoacids experience a strong increase in acidity when absorbing light and, hence, can be considered as molecular switches. The incorporation into amphiphilic block copolymers leads to novel stimuli-responsive materials with great potential.

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Reduction-Degradable Shell Cross-Linked Micelle with pH-Responsive Cores Prepared via Click Chemistry

Materials Science Forum ◽

10.4028/www.scientific.net/msf.848.527 ◽

2016 ◽

Vol 848 ◽

pp. 527-531

Author(s):

Lu Bin Lin ◽

Qing Yun Yu ◽

Zhuo Qun Gu ◽

Xiao Ze Jiang ◽

Mei Fang Zhu

Keyword(s):

Click Chemistry ◽

Self Assembly ◽

Gel Permeation Chromatography ◽

Proton Nuclear Magnetic Resonance ◽

Poly Ethylene Glycol ◽

H Nmr ◽

Transmission Electron ◽

Assembly Behavior ◽

Poly Ethylene ◽

Novel Drug

A well-defined poly [(ethylene glycol)-block-2-(dimethylamino) ethyl methacrylate-block-2-(diethylamino) methacrylate] (PEG-b-DMA-b-DEA) triblock copolymer was synthesized via atom transfer radical polymerization (ATRP) by successively polymerization of DMA and DEA monomers using a PEG-based macroinitiator, and obtained copolymer was then converted to be PEG-b-P(DMA-co-QDMA)-b-PDEA copolymer with “clickable” moieties in the middle block by the quaternization with propargyl bromide. Those copolymers prepared were characterized by proton Nuclear Magnetic Resonance (1H NMR) and Gel Permeation Chromatography (GPC), and its self-assembly behavior and subsequently fixation with bis-(azidoethyl) disulfide via click chemistry resulting reduction-sensitive shell-cross-linked (SCL) micelle in purely aqueous solution were investigated by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS). The results show the micellar structure could be effectively cross-linked via click chemistry and also be dissociated at reduction condition, which may realize it's potential application as novel drug delivery carriers.

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Correction: Novel azobenzene-based amphiphilic copolymers: synthesis, self-assembly behavior and multiple-stimuli-responsive properties

RSC Advances ◽

10.1039/c8ra90036a ◽

2018 ◽

Vol 8 (32) ◽

pp. 17878-17878

Author(s):

Yiting Xu ◽

Jie Cao ◽

Qi Li ◽

Jilu Li ◽

Kaiwei He ◽

...

Keyword(s):

Self Assembly ◽

Amphiphilic Copolymers ◽

Stimuli Responsive ◽

Assembly Behavior

Correction for ‘Novel azobenzene-based amphiphilic copolymers: synthesis, self-assembly behavior and multiple-stimuli-responsive properties’ by Yiting Xu et al., RSC Adv., 2018, 8, 16103–16113.

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Tailoring Peptide Self-Assembly and Formation of 2D Nanoribbons on Mica and HOPG Surface

Materials ◽

10.3390/ma15010310 ◽

2022 ◽

Vol 15 (1) ◽

pp. 310

Author(s):

Hao Kong ◽

Bin Liu ◽

Guozheng Yang ◽

Yun Chen ◽

Gang Wei

Keyword(s):

Self Assembly ◽

Ph Value ◽

Pyrolytic Graphite ◽

The Self ◽

Formation Mechanisms ◽

Three Dimension ◽

Material Interfaces ◽

The Creation ◽

Assembly Behavior ◽

And Function

Studying the interactions between biomolecules and material interfaces play a crucial role in the designing and synthesizing of functional bionanomaterials with tailored structure and function. Previously, a lot of studies were performed on the self-assembly of peptides in solution through internal and external stimulations, which mediated the creation of peptide nanostructures from zero-dimension to three-dimension. In this study, we demonstrate the self-assembly behavior of the GNNQQNY peptide on the surface of mica and highly oriented pyrolytic graphite through tailoring the self-assembly conditions. Various factors, such as the type of dissolvent, peptide concentration, pH value, and evaporation period on the formation of peptide nanofibers and nanoribbons with single- and bi-directional arrays are investigated. It is found that the creation of peptide nanoribbons on both mica and HOPG can be achieved effectively through adjusting and optimizing the experimental parameters. Based on the obtained results, the self-assembly and formation mechanisms of peptide nanoribbons on both material interfaces are discussed. It is expected that the findings obtained in this study will inspire the design of motif-specific peptides with high binding affinity towards materials and mediate the green synthesis of peptide-based bionanomaterials with unique function and application potential.

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Observing Effects of Calcium/Magnesium Ions and pH Value on the Self-Assembly of Extracted Swine Tendon Collagen by Atomic Force Microscopy

Journal of Food Quality ◽

10.1155/2017/9257060 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Xuan Song ◽

Zhiwei Wang ◽

Shiyu Tao ◽

Guixia Li ◽

Jie Zhu

Keyword(s):

Atomic Force Microscopy ◽

Metal Ions ◽

Self Assembly ◽

Food Packaging ◽

Ph Value ◽

The Self ◽

Solution Ph ◽

Collagen Concentration ◽

Force Microscopy ◽

Atomic Force

Self-assembly of extracted collagen from swine trotter tendon under different conditions was firstly observed using atomic force microscopy; then the effects of collagen concentration, pH value, and metal ions to the topography of the collagen assembly were analyzed with the height images and section analysis data. Collagen assembly under 0.1 M, 0.2 M, 0.3 M CaCl2, and MgCl2 solutions in different pH values showed significant differences (P < 0.05) in the topographical properties including height, width, and roughness. With the concentration being increased, the width of collagen decreased significantly (P < 0.05). The width of collagen fibers was first increased significantly (P < 0.05) and then decreased with the increasing of pH. The collagen was assembled with network structure on the mica in solution with Ca2+ ions. However, it had shown uniformed fibrous structure with Mg2+ ions on the new cleaved mica sheet. In addition, the width of collagen fibrous was 31~58 nm in solution with Mg2+ but 21~50 nm in Ca2+ solution. The self-assembly collagen displayed various potential abilities to construct fibers or membrane on mica surfaces with Ca2+ ions and Mg2+ irons. Besides, the result of collagen self-assembly had shown more relations among solution pH value, metal ions, and collagen molecular concentration, which will provide useful information on the control of collagen self-assembly in tissue engineering and food packaging engineering.

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Self-Assembly Behavior of a Stimuli-Responsive Water-Soluble [60]Fullerene-Containing Polymer

Langmuir ◽

10.1021/la048826s ◽

2004 ◽

Vol 20 (20) ◽

pp. 8569-8575 ◽

Cited By ~ 39

Author(s):

S. Dai ◽

P. Ravi ◽

C. H. Tan ◽

K. C. Tam

Keyword(s):

Self Assembly ◽

Water Soluble ◽

Stimuli Responsive ◽

Assembly Behavior

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Carbocycle-Based Organogelators: Influence of Chirality and Structural Features on Their Supramolecular Arrangements and Properties

Gels ◽

10.3390/gels7020054 ◽

2021 ◽

Vol 7 (2) ◽

pp. 54

Author(s):

Rosa M. Ortuño

Keyword(s):

Smart Materials ◽

Self Assembly ◽

Rational Design ◽

Structural Features ◽

Stimuli Responsive ◽

Polycyclic Compounds ◽

Relative Configuration ◽

Responsive Materials ◽

Self Assembling ◽

Donor Acceptor

The rational design and engineer of organogel-based smart materials and stimuli-responsive materials with tuned properties requires the control of the non-covalent forces driving the hierarchical self-assembly. Chirality, as well as cis/trans relative configuration, also plays a crucial role promoting the morphology and characteristics of the aggregates. Cycloalkane derivatives can provide chiral chemical platforms allowing the incorporation of functional groups and hydrophobic structural units able for a convenient molecular stacking leading to gels. Restriction of the conformational freedom imposed by the ring strain is also a contributing issue that can be modulated by the inclusion of flexible segments. In addition, donor/acceptor moieties can also be incorporated favoring the interactions with light or with charged species. This review offers a perspective on the abilities and properties of carbocycle-based organogelators starting from simple cycloalkane derivatives, which were the key to establish the basis for an effective self-assembling, to sophisticated polycyclic compounds with manifold properties and applications.

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Cooperative self-assembly of cyanines on carboxymethylamylose and other anionic scaffolds as tools for fluorescence-based biochemical sensing

Pure and Applied Chemistry ◽

10.1351/pac200678122313 ◽

2006 ◽

Vol 78 (12) ◽

pp. 2313-2323 ◽

Cited By ~ 21

Author(s):

David G. Whitten ◽

Komandoor E. Achyuthan ◽

Gabriel P. Lopez ◽

Oh-Kil Kim

Keyword(s):

Conformational Changes ◽

Self Assembly ◽

Random Coil ◽

Helical Structures ◽

Force Microscopy ◽

Helix Formation ◽

Biochemical Sensing ◽

Sensing Applications ◽

Atomic Force ◽

J Aggregates

We recently found that certain cyanines form tight complexes with carboxymethylamylose (CMA) in aqueous solutions and that in these complexes the cyanine exists as a strongly fluorescent and stable J-aggregate. Cyanine dyes are characterized by their ability to form J-aggregates showing very narrow absorption and fluorescence spectra relative to the monomer. Although they have found uses in sensing applications, the practicability has been limited in many cases due to the low quantum efficiencies for J-aggregate fluorescence. The CMA-cyanine complex is formed by a cooperative self-assembly in which both components undergo conformational changes during the association. The CMA exists as a random coil in solution prior to complex formation; helix formation is prevented due to repulsion of the charges on the carboxymethylated glucose units. The cyanine exists as a nonfluorescent monomer in the same solutions. A helical atomic force microscopy image and large induced circular dichroism (CD) spectra of the cyanine J-aggregate indicate that the self-assembly is a superhelix scaffold of CMA decorated with J-aggregates of the cyanine. Similar behavior was also observed with carboxymethylated cellulose (CMC). Enzymatic disruption of the helical structures (e.g., by the use of amylase to disrupt the structure of CMA helix) leads to the disappearance of the J-aggregate-associated fluorescence. The photophysical behavior and applications of this complex for sensing are discussed.

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