Coupled Metabolic Cycles Allow Out‐of‐Equilibrium Autopoietic Vesicle Replication

Abstract

We report chemically fuelled out-of-equilibrium selfreplicating vesicles based on surfactant formation. We studied the vesicles autocatalytic formation using UPLC to determine monomer concentration and interferometric scattering microscopy at the nanoparticle level. Unlike related reports of chemically fuelled self-replicating micelles, our vesicular system was too stable to surfactant degradation to be maintained out of equilibrium. The introduction of a catalyst, which introduces a second catalytic cycle into the metabolic network, was used to close the first cycle. This shows how coupled catalytic cycles can create a metabolic network that allows the creation and perseverance of fuel-driven, out-of-equilibrium self-replicating vesicles. One of the great challenges in chemistry is to mimic the complex living structures found in nature by designing artificial out-of-equilibrium systems. [1] These structures involve functional, dynamic states which require a continuous supply of energy to be sustained. [2] This energy can be supplied as a chemical fuel, or another energy source such as light. [3] Systems that use an energy supply to maintain behaviour that would otherwise not persist, are known as dissipative systems. [4] Upon depletion or removal of the energy source, the rates of destruction and formation become unbalanced and the system moves to thermodynamic equilibrium. By maintaining complex systems in an out-ofequilibrium state different behaviour can be observed compared to systems in equilibrium. This includes novel selfassembly processes, [5] material properties [6] and functionality. [7] Out-of-equilibrium systems are frequently encountered in phase-separated systems, where functionalities such as product selection [8] or self-regulation [9] can be observed. Especially interesting is the creation of synthetic supramolecular vesicles, since these resemble cellular structures found in nature. [10] Both functional transient vesicles, [11] and thermo-[*] Dr. A

Scattering-based Light Microscopy: From Metal Nanoparticles to Single Proteins

“…The ability to detect and image biological nanoparticles in aqueous solution naturally extends to lipids and the structures they form such as lipid nanodomains, lipid bilayers, and micelle and vesicle formation during autocatalytic processes. − iSCAT is particularly well-suited to this application, as it enables label-free visualization of chemical reactions by monitoring the production or destruction of nanoparticles. While nanoparticle formation can be monitored by bulk methods such as dynamic light scattering (DLS) , or NMR, the ability to detect individual particles provides access to the earliest stages of nanoparticle formation, often part of the “lag phase” caused by the invisibility of particles at very low concentrations for bulk methods.…”

Plant Cell-Inspired Membranization of Coacervate Protocells with a Structured Polysaccharide Layer

“…Microcompartments formed from self-assembly processes have been proposed as minimal cell-like entities (protocells) capable of molecular recruitment, confined chemical reactions, spatial separation, and information processing. 1−3 Examples of membrane-bound protocells include surfactant vesicles, 4,5 liposomes, 6,7 polymersomes, 8−10 emulsion droplets, 11−13 proteinosomes, 14−16 colloidosomes, 17−20 and capsules 21,22 that are prepared through the self-assembly of surfactants, lipids, polymers, protein−polymer conjugates, inorganic colloids, and layer-by-layer polyelectrolytes. Similar to the plasma membrane, the synthetic membranes surrounding protocells separate the internal components from the outside environments and guard the cell against various external stressors or substances.…”

Transient Biomacromolecular Nanoparticles for Labels with Self‐Erasable and Rewritable Ability

“…To date, various building blocks have been explored in the non‐equilibrium self‐assembly, such as small molecules, [4–13] copolymer, [14–17] peptide, [18,19] protein, [20,21] RNA, [22] DNA, [23–28] etc. Meanwhile, driven by chemical fuels, many kinds of transient structures, such as nanoparticles, [29–31] micelles, [15,32] vesicles, [6,10,33,34] aggregates, [16,35,36] fibers, [37,38] and hydrogels [39–44] have been studied. For example, the chemical fuel‐driven dissipative self‐assembly of vesicles was achieved from surfactants, in which the lifetimes of vesicles can be modulated by controlling the rate of adenosine triphosphate (ATP) hydrolysis, realizing the vesicles as transient chemical reactors [6] .…”

“…Inspired by naturally occurring systems, synthetic molecules have been used as building blocks in non‐equilibrium self‐assembly systems. To date, various building blocks have been explored in the non‐equilibrium self‐assembly, such as small molecules, [4–13] copolymer, [14–17] peptide, [18,19] protein, [20,21] RNA, [22] DNA, [23–28] etc. Meanwhile, driven by chemical fuels, many kinds of transient structures, such as nanoparticles, [29–31] micelles, [15,32] vesicles, [6,10,33,34] aggregates, [16,35,36] fibers, [37,38] and hydrogels [39–44] have been studied.…”