ChemSystemsChem最新文献

Nature utilizes non-equilibrium self-assembly to achieve remarkable functions. Although such systems have been synthesized, this class of assembly is only sparsely explored in innovative materials with life-like functions. Here, we report transient nanoparticles driven by adenosine triphosphate and their applications on the self-erasable and rewritable security labels. We show that the lifetime of transient nanoparticles can be tuned from a few minutes to hundreds of minutes through adjusting concentrations of the components. By integrating the transient nanoparticles into hydrogels, we achieve self-erasable and rewritable labels with time- and space-encoded information encryption. Notably, a smart Morse code is implemented by programming the hydrogel labels in a spatiotemporal manner. This work provides an emerging material involving transient nanoparticles for information encryption, further accelerating the explorations of the new type information encryption materials.

Relating supramolecular helices to the spontaneous resolution that generates conglomerate crystals is meaningful to the production of enantiopure compounds and to the understanding of natural homochirality as well. While homochiral elongation is favored along the axis of 1D supramolecular helical chains, conglomerate crystallization requires a 3D homochiral framework. This inspires us to explore new avenues to the spontaneous resolution through the formation of multiple supramolecular helices during crystallization. This Concept outlines and reviews multiple supramolecular helices found in the conglomerate crystals, i. e. three supramolecular helices along one crystallographic axis and two or three supramolecular helices along different crystallographic axes, followed by our observations of homochiral elongation of the helicity of the helical building blocks, the azapeptides, during the formation of supramolecular helices, as well as the spontaneous resolution of amino acid alanine that is made into a helical azapeptide derivative via the formation of supramolecular helices along two different crystallographic axes.

Cells possess a number of active segregation machineries for both chromosomal and large extrachromosomal DNA elements to avoid stochastic loss during cell division. In contrast, system that can be exploited for active, general segregation of RNA molecules including mRNAs or self-replicating RNA constructs are currently lacking. Here, we present an artificial RNA segregation system derived from the bacterial type II ParMRC plasmid segregation system and the RNA coliphage MS2. We show that fusing the partition protein ParR with the MS2 RNA coat protein enables specific binding to microbeads decorated with RNA-repeats of the archetypical MS2 RNA operator hairpin. Addition of the actin homologue ParM protein triggers efficient and rapid microbeads segregation via ATP-dependent ParM polymerization. Our new RNA partitioning system could be used for specific localization of mRNAs and/or the stable maintenance of self-replicating RNA vectors in various contexts such as living and artificial cells.

Based on the motifs (RNISY (M) and DEEVELILGDT (D)) in the protein crystal structures of Merlin and CRL4^DCAF−1, we phosphorylated the tyrosine residue in M and conjugated M to a self-assembling motif to produce a phosphopeptide (1P) and examined enzyme-instructed self-assembly (EISA) of 1P with and without the presence of D (4). Our results show that EISA of 1P forms a hydrogel at exceedingly low volume fraction (∼0.03 %) even with the presence of the hydrophilic peptide, 4. Unlike 1P, 2P (a diastereomer of 1P) or 3P (the enantiomer of 1P) forms a hydrogel via EISA when their concentration is four or three times that of 1P, respectively. Circular dichroism (CD) spectra show that increasing the concentration of the phosphopeptides lowers the CD signals of the mixtures, and the magnitudes of the CD signals depends on the interaction between M and D. This work provides insight for understanding multi-component hydrogels formed by self-assembly, which involves both specific intermolecular interaction and enzymatic reactions.

Into another year with ChemSystemsChem! In this Editorial, the editors summarize the developments at the journal in 2022, highlight new projects for 2023 and introduce the renewed Editorial Advisory Board.

The autonomous activation of acid-autocatalyzed sulfite–halogenate (iodate, bromate, chlorate) reactions is programmed using slow acid generators (δ-gluconolactone GL, and 1,3-propanesultone PrS). A remarkable correlation is found between the pH- and temperature-time profiles, especially for the chlorate–sulfite–GL system. Further optimization of the latter resulted in a chemical system able to generate sudden temperature and pH changes after a tailorable induction time, that is a “thermochemical clock”.

The Cover Feature shows a network of interacting peptide components that illustrates complex peptide-based systems. System complexity is built from the bottom-up through self-organization and functional reconfiguration of interacting and inter-converting peptide sequences. Cover design by Ella Maru Studio. More information can be found in the Review by Salma Kassem and Rein V. Ulijn.

Autocatalysis induces nonlinearity in chemical and/or biological systems, and is important for understanding the emergence of life in nature. To enhance the autonomy of self-propulsion in an open system, we introduced a Briggs–Rauscher (BR) reaction into self-propelled droplet systems. In this study, a droplet composed of a BR solution in an oil phase containing a monoolein surfactant exhibited various types of motion, that is, continuous, oscillatory, and no motions of the droplet. The motions observed depended on the concentrations of potassium iodate and hydrogen peroxide in the BR solution. These results indicated that the driving force in this system was generated by the reaction between monoolein and one of the intermediates of the BR reaction, iodine. Our system can contribute to the establishment of a novel biomimetic object in which the autocatalytic process acts as a key factor for inducing various types of motion.

Stimuli-responsive, optically-active colloidal systems are convenient signal transducers capable of monitoring environmental changes at the nanoscale. We report on the coupling of chemo-thermal cycloaddition reaction with temperature-sensitive, DNA-coated gold nanoparticles. We found that the concentration of chemical fuel, dictating the temperature of the mixture, is a primary ingredient in controlling the extent of the reversible clustering of gold nanoparticles. Our results show that rational coupling of chemical and colloidal systems can open up new possibilities in tracking the change of local temperature using aggregation/redispersion of nanoparticles.

The front cover artwork is provided by BoekhovenLab at TU Munich. The image shows an energy landscape of kinetically trapped chemically fueled supramolecular fibers, which reminds of a mountain landscape. Read the full text of the Research Article at 10.1002/syst.202200035.