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In living systems, dissipative processes are driven by the endergonic hydrolysis of chemical fuels such as nucleoside triphosphates. Now, through a simple model system, a transient self‐assembled state is realized by utilizing the catalytic effect of histidine on the formation and breaking of ester bonds. First, histidine facilitates the ester bond formation, which then rapidly co‐assembles to form a self‐supporting gel. An out‐of‐equilibrium state is realized owing to the cooperative catalysis by the proximal histidines in the assembled state, driving the second pathway and resulting in disassembly to sol. Cooperative effects that use the dual role of imidazoles as nucleophile and as proton donor is utilized to achieve transient assemblies. This simple system mimics the structural journey seen in microtubule formation where the substrate GTP facilitates the non‐covalent assembly and triggers a cooperative catalytic process, leading to substrate hydrolysis and subsequent disassembly. Self‐driving: A simple fuel‐driven self‐assembled system is demonstrated that achieves an out‐of‐equilibrium state by dissipating energy from the assembled structures. This occurs by utilizing cooperative effects of the proximally located histidines, which catalyze the hydrolysis of ester bonds of the lipid‐tailed amphiphile. [ABSTRACT FROM AUTHOR]

Cover Feature: Disulphide Cross-Linked Ultrashort Peptide Hydrogelator for Water Remediation (Chem. Eur. J. 37/2023) Keywords: disulphide; dye removal; hydrogels; peptides; self-assembly EN disulphide dye removal hydrogels peptides self-assembly 1 1 1 07/05/23 20230703 NES 230703 B Unleashing the power of peptide hydrogels for environmental remediation b : This is a tale of an ultrashort peptide hydrogel (azo-KC) and its efficiency for wastewater treatment. Disulphide, dye removal, hydrogels, peptides, self-assembly. [Extracted from the article]

Abstract: A tandem sensor for Pd2+ and CN− ions based on perylenediimide‐peptide conjugate is reported. The probe showed high selectivity toward Pd2+ ion over other metal cations and the sensitivity was observed to be 0.55 ppb, significantly lower than other similar chemosensors. Binding with Pd2+ leads to aggregation of the ligand and consequently results in quenching of its emission. The quenched emission can be turned on in presence of CN− ions as the cyanides form stronger complex with Pd2+ leading to disaggregation of the aggregated system. The system was found to be extremely selective to CN− and the detection limit in this case was calculated to be as low as 0.226 ppb. The sensor is also utilized to construct a practical and simple TLC based tool to sense these two ions efficiently. [ABSTRACT FROM AUTHOR]

A systematic study of the self-assemblyprocess of a viologen-containingsurfactant in aqueous medium is reported. Dodecyl-ethyl-viologendibromide(DDEV) is mixed in different proportions with dodecyltrimethylammoniumbromide (DTAB), and the physicochemical properties of micellizationare evaluated in order to find a suitable combination which does notinterfere with the micellar properties of DTAB but introduces thecharacteristic properties of viologen. In this process, 1% dopingof DDEV with DTAB was found to be the most appropriate, as negligiblechanges were observed in the physicochemical behavior of this systemwith respect to that of pure DTAB. The 1% DDEV-doped DTAB mixed micellarsystem showed the characteristic two-step reduction process for theviologen units at the interface as revealed by CV experiments. 1%mixing of DDEV with DTAB also allowed us to prepare stable w/o microemulsionscontaining viologen units at the interface which is otherwise unattainablewith pure viologen surfactants. The charge-transfer capability ofthe viologen unit to the electron-rich 2,6-dihydroxynaphthalene (DHN)moiety inside the macrocyclic host, cucurbit[8]uril (CB[8]) is alsoevaluated for this system, and surprisingly even at this very lowconcentration, the ternary complex of DDEV-DHN@CB[8] transformed themicellar assembly to uniform vesicles. All of these properties havebeen further extended to other tetraalkylammonium surfactants, andsimilar effects were observed. [ABSTRACT FROM AUTHOR]

A lysine based peptide amphiphile(PA) is designed and synthesizedfor efficient water immobilization. The PA with a minimum gelationconcentration (MGC) of 1% w/v in water shows prolonged stability andcan also efficiently immobilize aqueous mixtures of some other organicsolvents. The presence of a free amine induced pH dependency of thegelation as the PA could form hydrogel at a pH range of 1–8but failed to do so above that pH. Various spectroscopic and microscopicexperiments such as steady state fluorescence, NMR, IR, CD, and FESEMreveal the presence of hydrophobic interaction, hydrogen bond, andπ–π stacking interaction in the self-assembly process.The self-aggregation has been correlated with the design of the moleculeto show the involvement of supramolecular forces and the hierarchicalpathway. While the L analogue formed left-handed helical nanofibers,the other enantiomer showed opposite helicity. Interestingly the equimolarmixture of the isomers failed to form any fibrous aggregate. Althoughfibers formed at a subgel concentration, no helical nature was observedat this stage. The length and thickness of the fibers increased withincrease in the gelator concentration. The nanofibers formed by thegelator are used as a template to prepare mesoporous single wall silicananotubes (SWSNTs) in situ in plain water without the requirementof any organic solvent as well as any external hydrolyzing agent.The SWSNTs formed are open at both ends, are few micrometers in length,and have an average diameter of ∼10 nm. The BET isotherm showeda type IV hysteresis loop suggesting mesoporous nature of the nanotubes. [ABSTRACT FROM AUTHOR]

A single amino acid in a peptide sequence can play an important role to tune the self-assembly and hydrogelation behaviour. Here, a C-terminal cysteine-containing ultrashort peptide hydrogelator forms hydrogel through non-covalent and covalent interactions. Interestingly, the hydrogel is insoluble in water and buffer solutions at different pH values (1-13) and is thixotropic and injectable. In recent years, removing dyes from contaminated water has become a significant concern because of the shortage of freshwater resources. Therefore, the adsorption of dyes through a reliable, straightforward, nontoxic, cheap, and environmentally friendly adsorbent has become a popular topic. Hence, the hydrogelator was exploited to remove organic dyes from wastewater, harnessing its applicability in the gel phase and solid supports (filter paper and cotton)., (© 2023 Wiley-VCH GmbH.)

Cation-π and charge-transfer (CT) interactions are ubiquitous in nature and involved in several biological processes. Although the origin of both the interactions in isolated pairs has extensively been studied, CT interactions are more prominent in supramolecular chemistry. Involvement of cation-π interactions in the preparation of advanced functional soft materials is uncommon. Moreover, a combination of these two interactions within a pair of electron donor (D) and acceptor (A) is uncharted. Here, we present a rational design to incorporate a combination of these two interactions within a D-A pair. A pyrene-peptide conjugate exhibits a combination of cation-π and CT interactions with a cationic naphthalenediimide (NDI) molecule in water. Nuclear Overhauser effect spectroscopy NMR along with other techniques and density functional theory calculations reveal the involvement of these interactions. The π-planes of pyrene and NDI adopt an angle of 56° to satisfy both the interactions, whereas β-sheet formation by the peptide sequence facilitates self-assembly. Notably, the binary system forms a self-supporting hydrogel at a higher concentration. The hydrogel shows efficient self-healing and injectable property. The hydrogel retains its thixotropic nature even at an elevated temperature. Broadly, we demonstrate a pathway that should prove pertinent to various areas, ranging from understanding biological assembly to peptide-based functional soft materials.

In living systems, dissipative processes are driven by the endergonic hydrolysis of chemical fuels such as nucleoside triphosphates. Now, through a simple model system, a transient self-assembled state is realized by utilizing the catalytic effect of histidine on the formation and breaking of ester bonds. First, histidine facilitates the ester bond formation, which then rapidly co-assembles to form a self-supporting gel. An out-of-equilibrium state is realized owing to the cooperative catalysis by the proximal histidines in the assembled state, driving the second pathway and resulting in disassembly to sol. Cooperative effects that use the dual role of imidazoles as nucleophile and as proton donor is utilized to achieve transient assemblies. This simple system mimics the structural journey seen in microtubule formation where the substrate GTP facilitates the non-covalent assembly and triggers a cooperative catalytic process, leading to substrate hydrolysis and subsequent disassembly., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)