ChemSystemsChem最新文献

Self-organizing behaviors have long been studied in complex chemical systems involving a nonlinear chemical feedback (e. g. the Belousov-Zhabotinsky and Bray-Liebhafsky reactions). Here we explore the emergence of oscillatory dynamics by coupling simpler chemical processes, in the form of a bimolecular reaction, and natural convection (i. e. flows induced by changes in density and surface tension occurring during the reaction). We study and classify different possible scenarios based on the interplay between chemically-driven Marangoni- (surface tension induced) and buoyancy-driven (density induced) flows. This coupling can either be antagonistic, whereby both generated flows are opposing (e. g. a reaction increasing the surface tension and decreasing the density), or cooperative if both flows act in the same direction (e. g. a reaction increasing both surface tension and density). We further investigate the impact of these oscillations on the mixing and reaction rate.

Research across various disciplines shows the benefits of learning and memory for gaining functionality and improving performance. It is increasingly clear that learning and memory can be found in both physical and virtual systems, from intelligent life forms to machines, simple organisms, and even designed chemical systems. We are interested in understanding to what extent physical embodiments of these processes can be synthesized and engineered from the bottom up by using molecular components. In this perspective, we raise and attempt to answer conceptual questions about supramolecular systems as the smallest units capable of learning. We define learning as a process where a complex system of interacting components modifies itself in response to an applied stress or stimulus, resulting in structural changes and information gain. We highlight the potential of systems chemistry and molecular networks to design systems that meet this definition by encoding, decoding, and storing information as memory within the system′s composition. Understanding the physical basis of molecular memory and learning could inform the development of materials and chemical systems that autonomously acquire new properties in response to their environment. This could also provide insights for next-generation computing and physical, rather than virtual, learning systems.

Spatiotemporal patterns, such as spiral waves, can be formed on membranes and are coupled with membrane deformation. The membrane can exhibit no-thermal fluctuations owing to active protein interactions. The Review by Hiroshi Noguchi describes the latest developments in theoretical analyses and simulations on nonequilibrium dynamics of biomembranes under active protein interactions and chemical reactions.

Liposomes have attracted attention as a compartment for various synthetic biomolecular systems, including artificial cells and drug delivery carriers. Notably, micrometer-sized liposomes (MSLs) have emerged as a key platform for engineering de novo biomolecular systems, extending beyond their role as model compartments in scientific research. However, there is still a lack of reviews on MSLs from the perspective of artificial systems across various disciplines from basic sciences to applied sciences and to engineering. In this review, we aim to fill this gap by providing a hierarchical breakdown that offers a systematic overview of MSL design and experimental methods. Primarily targeted at readers new to the field, our review presents a unified description of MSL-based functional systems and guidance on experimental details such as lipid composition and preparation methods. Our approach seeks to present a consolidated perspective of functionalized liposomes as an artificial system, contributing to advancements across various disciplines.

RNA is an information-carrying molecule that instructs protein synthesis, but it also functions as a catalyst in so-called ribozymes. Here, we study this multifunctional character using a dynamic combinatorial library powered by chemical fuel. On the one hand, we demonstrate that RNA templates the oligomerization and inhibits deoligomerization. On the other hand, we show that RNA can be a structural element in the formation of hydrogels. Moreover, in its hydrogel, RNA degradation by nucleases is accelerated. Thus, templates have a role beyond blueprints, protectors, and selectors. Template-oligomer interactions can create new (micro)environments that might affect evolutionary dynamics.

There is great interest in developing small synthetic molecules that imitate some of the functions and behaviour of living beings. Here, we describe the structural screening of peptide amphiphiles with autocatalytic self-replication, which mimics the perpetuation mechanisms of living matter. Our design uses two reactive precursors to generate self-assembling peptide amphiphiles, which form micelles that catalyse their own synthesis. A collection of precursors with varying sizes was screened combinatorially, revealing a minimal tripeptide amphiphile required to trigger autocatalytic self-replication. These results contribute to the structural simplification of synthetic supramolecular monomers with life-like behaviour.

Anionic biomembranes are vital features of all living cells and were perhaps key components of the earliest cell-like structures – protocells. In the absence of evolved protein machinery, any protocell membranes would have had their properties heavily influenced by the ambient environment, posing a systems chemistry challenge to understanding how such membranes functioned. Here we use a range of techniques to examine the effect of glycine and lysine, representative neutral and cationic amino acids, on the properties of model anionic membranes composed of equimolar POPC and POPG. Using QCM−D and neutron reflectometry, we find that unlike glycine, lysine strongly binds to the membrane, resulting in significant lipid loss and changes in the scattering length density and volume fraction of the lipids in the bilayer. Interestingly, we also find that even though lysine causes substantial changes in the physicochemical and structural properties of the anionic membrane, permeability studies show that lysine cannot permeate while glycine can, highlighting a disconnect between the structural changes observed for low curvature systems and the permeability trends observed in high curvature systems. This research provides mechanistic insights into single amino acid-anionic biomembrane interactions, and how they could have impacted evolving protocell membrane functions and stability.

Protocell membranes were likely formed through primitive metabolic reactions that synthesized more complex membrane lipid species from simpler precursors. Thioacids have been shown to be prebiotically plausible and chemoselective N-acylating reagents. They have been successfully employed for the acylation of peptides and RNA. However, the ability of thioacids to acylate lipid species has not yet been explored. Here, we demonstrate N-acylation of natural amine-containing amphiphiles using fatty thioacids. This reaction occurs spontaneously in aqueous conditions and is chemoselective,and traceless. The synthesis of several natural sphingolipids via direct N-acylation is possible and their subsequent de novo formation into vesicular membranes is shown. Aqueous thioacid coupling provides a route for generating membrane-forming lipids in the context of protocells and for the in situ synthesis of relevant sphingolipid species.

Regulating the formation and dissolution of active complex coacervate droplets with chemical reactions offers a powerful synthetic cell model. Such active droplets are also helpful in understanding the non-equilibrium nature of membrane-less organelles. Like many membrane-less organelles, these droplets rely on high-chemical potential reagents, like ATP, to maintain their transient nature. This study explores Activated Carboxylic Acids (ACAs) as a high-chemical potential fuel to modulate the lifetime of peptide-based coacervates through transient pH changes. We demonstrate that nitroacetic acid, a commonly used ACA, can effectively induce the formation and dissolution of coacervates by transiently altering the solution′s pH. The system, comprising the zwitterionic peptide Ac-FRGRGD-OH and polyanions, forms coacervates upon protonation at low pH and dissolves as the pH returns to neutral. Our findings indicate that the lifetime of these synthetic cells can be fine-tuned by varying the amount of ACA added, and the system can be refueled multiple times without significant interference from by-products. This ACA-driven reaction cycle is versatile, accommodating various coacervate compositions and enabling the uptake of diverse compounds, making it a valuable model for compartmentalization. The study underscores the potential of ACA-fueled coacervates as a platform for investigating biomolecular condensates and developing synthetic life systems.

Pursuing non-equilibrium chemistry with (bio)molecules is of utmost importance for the design of life-like dynamic materials that emerge in a constant flux of energy. Herein, we explore spatial localization of dissipative self-assembly of biocondensate (DNA-histone) via passing chemical fuel (histone) and one fuel-degrading agent (trypsin) through two arms of the Y-shaped microfluidic chip. In this case, a continuous supply of fuel and fuel-degrading agent results self-assembly of biocondensate, maintaining a non-equilibrium steady state (NESS). We find in the presence of gradient of dissipating conditions, the formation zone of biocondensate drifts towards fuel-rich zone (away from dissipating zone). In absence of fuel-degrading agent, diffusive transport of free DNA towards histone channel (perpendicular to advection) is restricted as it formed much larger micron-sized biocondensate at the center of the channel (the meeting point of two flows). However, this sidewise DNA diffusion is operative in the presence of fuel-degrading agent and therefore, the formation zone shifted to histone-rich zone. Furthermore, we demonstrate that in the presence of trypsin, catalytic DNA's peroxidase reactivity can be moved to histone-rich region. Transposition of self-assembly process in a gradient of dissipative conditions will be of importance in the development of spatially-controlled chemistry, reaction-diffusion processes.