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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]

Abstract: To develop a new sensor for histone, a series of Naphthalenediimide (NDI) derivatieves were subjected to DNA binding studies and the NDI derivative with strongest affinity for DNA was selected. This NDI‐DNA hybrid is used for highly selective and sensitive detection of a DNA binding protein, histone which dislodges the intercalated NDI groups and thus “turn‐on” the emission. [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). [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]

Herein, we report the catalytic potential of short peptide based cross-β amyloid nanotubes with surface exposed histidine capable of binding hemin and showing facile cascade reactions, playing the dual roles of hydrolases and peroxidases, two of the most important classes of enzymes in extant biology. The activity of these simple systems exceeded those of modern and larger proteins like cytochrome C and hemoglobin. Further, evidence suggested that these self-assembled nanotubes foreshadow the process of intermediate channeling, a feature seen in the case of advanced enzymes. [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]

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. [ABSTRACT FROM AUTHOR]

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]

This study reports the self-assembly and application of a naphthalene diimide (NDI)-appended peptide amphiphile (PA). H-bonding among the peptide moiety in conjunction with p-stacking between NDI and hydrophobic interactions within the alkyl chain are the major driving forces behind the stepwise aggregation of the PA to form hydrogels. The PA produced efficient self-assemblies in water, forming a nanofibrous network that further formed a self-supportive hydrogel. The molecule followed a three-step self-assembly mechanism. At a lower concentration (50 µM), it forms extremely small aggregates with a very low population of the molecules. With an increase in concentration, spherical aggregates are formed above 450 µM concentration. Importantly, this water-soluble conjugate was found to be nontoxic, cell permeable, and usable for cell imaging. Moreover, the aggregation process and consequently the emission behavior are highly responsive to the pH of the medium. Thus, the pH responsive aggregation and emission behavior has an extended biological application for assessing intracellular pH. The biocompatibility and intracellular pH determining capability suggest it is a promising candidate for use as a supramolecular material in biomedical applications. [ABSTRACT FROM AUTHOR]