Communication and Cross-Regulation between Chemically Fueled Sender and Receiver Reaction Networks

Non-Equilibrium Dissipative Assembly with Switchable Biological Functions

Natural dissipative assembly (DSA) often exhibit energy-driven shifts in natural functions. However, creating man-made DSA that can mimic such biological activities transformation remains relatively rare. Herein, we introduce a cytomembrane-like dissipative assembly system based on chiral supramolecules. This system employs benzoyl cysteine in an out of equilibrium manner, enabling the shifts in biofunctions while minimizing material use. Specifically, aroyl-cystine derivatives primarily assemble into stable M-helix nanofibers under equilibrium conditions. These nanofibers enhance fibroblast adhesion and proliferation through stereospecific interactions with chiral cellular membranes. Upon the addition of chemical fuels, these functional nanofibers temporarily transform into non-equilibrium nanospheres, facilitating efficient drug delivery. Subsequently, these nanospheres revert to their original nanofiber state, effectively recycling the drug. The programmable function-shifting ability of this DSA establishes it as a novel, fuel-driven drug delivery vehicle. And the bioactive DSA not only addresses a gap in synthetic DSAs within biological applications but also sets the stage for innovative designs of 'living' materials.

Transient Covalent Polymers through Carbodiimide-Driven Assembly

Biochemical systems make use of out-of-equilibrium polymers generated under kinetic control. Inspired by these systems, many abiotic supramolecular polymers driven by chemical fuel reactions have been reported. Conversely, polymers based on transient covalent bonds have received little attention, even though they have the potential to complement supramolecular systems by generating transient structures based on stronger bonds and by offering a straightforward tuning of reaction kinetics. In this study, we show that simple aqueous dicarboxylic acids give poly(anhydrides) when treated with the carbodiimide EDC. Transient covalent polymers with molecular weights exceeding 15,000 are generated which then decompose over the course of hours to weeks. Disassembly kinetics can be controlled using simple substituent effects in the monomer design. The impact of solvent polarity, carbodiimide concentration, temperature, pyridine concentration, and monomer concentration on polymer properties and lifetimes has been investigated. The results reveal substantial control over polymer assembly and disassembly kinetics, highlighting the potential for fine-tuned kinetic control in nonequilibrium polymerization systems.

A facile DNA coacervate platform for engineering wetting, engulfment, fusion and transient behavior

Biomolecular coacervates are emerging models to understand biological systems and important building blocks for designer applications. DNA can be used to build up programmable coacervates, but often the processes and building blocks to make those are only available to specialists. Here, we report a simple approach for the formation of dynamic, multivalency-driven coacervates using long single-stranded DNA homopolymer in combination with a series of palindromic binders to serve as a synthetic coacervate droplet. We reveal details on how the length and sequence of the multivalent binders influence coacervate formation, how to introduce switching and autonomous behavior in reaction circuits, as well as how to engineer wetting, engulfment and fusion in multi-coacervate system. Our simple-to-use model DNA coacervates enhance the understanding of coacervate dynamics, fusion, phase transition mechanisms, and wetting behavior between coacervates, forming a solid foundation for the development of innovative synthetic and programmable coacervates for fundamental studies and applications.

Artificial Homeostasis Systems Based on Feedback Reaction Networks: Design Principles and Future Promises

Feedback-controlled chemical reaction networks (FCRNs) are indispensable for various biological processes, such as cellular mechanisms, patterns, and signaling pathways. Through the intricate interplay of many feedback loops (FLs), FCRNs maintain a stable internal cellular environment. Currently, creating minimalistic synthetic cells is the long-term objective of systems chemistry, which is motivated by such natural integrity. The design, kinetic optimization, and analysis of FCRNs to exhibit functions akin to those of a cell still pose significant challenges. Indeed, reaching synthetic homeostasis is essential for engineering synthetic cell components. However, maintaining homeostasis in artificial systems against various agitations is a difficult task. Several biological events can provide us with guidelines for a conceptual understanding of homeostasis, which can be further applicable in designing artificial synthetic systems. In this regard, we organize our review with artificial homeostasis systems driven by FCRNs at different length scales, including homogeneous, compartmentalized, and soft material systems. First, we stretch a quick overview of FCRNs in different molecular and supramolecular systems, which are the essential toolbox for engineering different nonlinear functions and homeostatic systems. Moreover, the existing history of synthetic homeostasis in chemical and material systems and their advanced functions with self-correcting, and regulating properties are also emphasized.

A non-equilibrium dissipation system with tunable molecular fuel flux

Cells convert macromolecule fuel into small molecule fuel through energy pathways, including glycolysis, the citric acid cycle, and oxidative phosphorylation. These processes drive vital dissipative networks or structures. Distinct from direct fuel (DF) utilization (directly acquire and utilize small molecule fuel), this macromolecule fuel mechanism is referred to as indirect fuel (IF) utilization, wherein the generation rate of small molecule fuel (fuel flux) can be effectively regulated. Here, we reported a bionic dissipation system with tunable fuel flux based on dynamic DNA nanotechnology. By regulating the rates of strand displacement and enzymatic reactions, we controlled the fuel flux and further tuned the strength of non-equilibrium transient states. Interestingly, we found that within a certain range, the fuel flux was positively correlated with the strength of the transient state. Once saturation was reached, it became negatively correlated. An appropriate fuel flux supports the maintenance of high-intensity non-equilibrium transients. Furthermore, we harnessed the dissipation system with tunable molecular fuel flux to regulate the dynamic assembly and disassembly of AuNPs. Different fuel fluxes resulted in varying assembly and disassembly rates and strengths for AuNPs, accomplishing a biomimetic process of regulating microtubule assembly through the control of fuel flux within living organisms. This work demonstrated a dissipation system with tunable molecular fuel flux, and we envision that this system holds significant potential for development in various fields such as biomimetics, synthetic biology, smart materials, biosensing, and artificial cells.

Transient Transcription Machineries Modulate Dynamic Functions of G-Quadruplexes: Temporal Regulation of Biocatalytic Circuits, Gene Replication and Transcription

Native G-quadruplex-regulated temporal biocatalytic circuits, gene polymerization, and transcription processes are emulated by biomimetic, synthetically engineered transcription machineries coupled to reconfigurable G-quadruplex nanostructures. These are addressed by the following example: (i) A reaction module demonstrates the fuel-triggered transcription machinery-guided transient synthesis of G-quadruplex nanostructures. (ii) A dynamically triggered and modulated transcription machinery that guides the temporal separation and reassembly of the anti-thrombin G-quadruplex aptamer/thrombin complex is introduced, and the transient thrombin-catalyzed coagulation of fibrinogen is demonstrated. (iii) A dynamically fueled transient transcription machinery for the temporal activation of G-quadruplex-topologically blocked gene polymerization circuits is introduced. (iv) Transcription circuits revealing G-quadruplex-promoted or G-quadruplex-inhibited cascaded transcription machineries are presented. Beyond advancing the rapidly developing field of dynamically modulated G-quadruplex DNA nanostructures, the systems introduce potential therapeutic applications.