Self-Assembly of Decoupled Borazines on Metal Surfaces: The Role of the Peripheral Groups

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.

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Sticky ends in a self-assembling ABA triblock copolymer: the role of ureas in stimuli-responsive hydrogels

Molecular Systems Design & Engineering ◽

10.1039/c8me00063h ◽

2019 ◽

Vol 4 (1) ◽

pp. 91-102 ◽

Cited By ~ 5

Author(s):

Ryan T. Shafranek ◽

Joel D. Leger ◽

Song Zhang ◽

Munira Khalil ◽

Xiaodan Gu ◽

...

Keyword(s):

Self Assembly ◽

Viscoelastic Properties ◽

Triblock Copolymer ◽

Thermal Response ◽

Stimuli Responsive ◽

Self Assembling ◽

Polymeric Hydrogels ◽

Aba Triblock Copolymer ◽

Responsive Hydrogels

Directed self-assembly in polymeric hydrogels allows tunability of thermal response and viscoelastic properties.

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Understanding the role of conjugation length on the self-assembly behaviour of oligophenyleneethynylenes

Chemical Communications ◽

10.1039/d1cc01054a ◽

2021 ◽

Author(s):

Beatriz Matarranz ◽

Goutam Ghosh ◽

Ramesh Kandanelli ◽

Angel Sampedro ◽

Kalathil K. Kartha ◽

...

Keyword(s):

Self Assembly ◽

The Self ◽

Conjugation Length ◽

The Relationship

We unravel the relationship between conjugation length and self-assembly behaviour of oligophenyleneethynylenes (OPEs).

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On the Role of Peripheral H‐bonding Directors in the Tubular Self‐assembly of Dinucleobase Monomers

ChemPlusChem ◽

10.1002/cplu.202100255 ◽

2021 ◽

Author(s):

Violeta Vázquez-González ◽

María J. Mayoral ◽

Fatima Aparicio ◽

Paula Martínez-Arjona ◽

David Gonzalez Rodriguez

Keyword(s):

Self Assembly

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Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

Polymers ◽

10.3390/polym13111729 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1729

Author(s):

Patrizio Raffa

Keyword(s):

Surface Tension ◽

Self Assembly ◽

Interaction Model ◽

Industrial Applications ◽

Molecular Organization ◽

Different Types ◽

Solution Rheology ◽

Interesting Class ◽

First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

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Substrate wettability guided oriented self assembly of Janus particles

Scientific Reports ◽

10.1038/s41598-020-80760-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Meneka Banik ◽

Shaili Sett ◽

Chirodeep Bakli ◽

Arup Kumar Raychaudhuri ◽

Suman Chakraborty ◽

...

Keyword(s):

Self Assembly ◽

Janus Particles ◽

Water Molecules ◽

Functional Coatings ◽

Hexagonal Close Packed ◽

Local Densities ◽

Inhomogeneous Properties ◽

Metal Polymer ◽

Specific Orientation

AbstractSelf-assembly of Janus particles with spatial inhomogeneous properties is of fundamental importance in diverse areas of sciences and has been extensively observed as a favorably functionalized fluidic interface or in a dilute solution. Interestingly, the unique and non-trivial role of surface wettability on oriented self-assembly of Janus particles has remained largely unexplored. Here, the exclusive role of substrate wettability in directing the orientation of amphiphilic metal-polymer Bifacial spherical Janus particles, obtained by topo-selective metal deposition on colloidal Polymestyere (PS) particles, is explored by drop casting a dilute dispersion of the Janus colloids. While all particles orient with their polymeric (hydrophobic) and metallic (hydrophilic) sides facing upwards on hydrophilic and hydrophobic substrates respectively, they exhibit random orientation on a neutral substrate. The substrate wettability guided orientation of the Janus particles is captured using molecular dynamic simulation, which highlights that the arrangement of water molecules and their local densities near the substrate guide the specific orientation. Finally, it is shown that by spin coating it becomes possible to create a hexagonal close-packed array of the Janus colloids with specific orientation on differential wettability substrates. The results reported here open up new possibilities of substrate-wettability driven functional coatings of Janus particles, which has hitherto remained unexplored.

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Astral hydrogels mimic tissue mechanics by aster-aster interpenetration

Nature Communications ◽

10.1038/s41467-021-24663-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Qingqiao Xie ◽

Yuandi Zhuang ◽

Gaojun Ye ◽

Tiankuo Wang ◽

Yi Cao ◽

...

Keyword(s):

Common Core ◽

Self Assembly ◽

Master Curve ◽

Soft Tissues ◽

Tissue Mechanics ◽

Fresh Perspective ◽

Single Master Curve ◽

Unique Mechanism ◽

Gel Network

AbstractMany soft tissues are compression-stiffening and extension-softening in response to axial strains, but common hydrogels are either inert (for ideal chains) or tissue-opposite (for semiflexible polymers). Herein, we report a class of astral hydrogels that are structurally distinct from tissues but mechanically tissue-like. Specifically, hierarchical self-assembly of amphiphilic gemini molecules produces radial asters with a common core and divergently growing, semiflexible ribbons; adjacent asters moderately interpenetrate each other via interlacement of their peripheral ribbons to form a gel network. Resembling tissues, the astral gels stiffen in compression and soften in extension with all the experimental data across different gel compositions collapsing onto a single master curve. We put forward a minimal model to reproduce the master curve quantitatively, underlying the determinant role of aster-aster interpenetration. Compression significantly expands the interpenetration region, during which the number of effective crosslinks is increased and the network strengthened, while extension does the opposite. Looking forward, we expect this unique mechanism of interpenetration to provide a fresh perspective for designing and constructing mechanically tissue-like materials.

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