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

Harnessing autocatalytic reactions in polymerization and depolymerization

“…iSCAT observations were corroborated with measurements acquired from fluorescence spectrometry [72] as well as ultra-performance liquid chromatography (UPLC). [74] More importantly, iSCAT exhibited decisive advantages (due to its high sensitivity) over dynamic light scattering (DLS) for allowing verification of the nucleation stage as the reaction proceeded. During iSCAT, multiple binding events may cause undercounting when the concentration of aggregate particles is high, and iSCAT is not able to visualize the growth of formed vesicles.…”

Dissipative Dynamic Covalent Chemistry (DDCvC) Based on the Transimination Reaction

“…The idea of dynamic combinatorial libraries far from equilibrium has been recently explored by Boekhoven et al, [21] Fletcher et al, [22] and the Otto group. [23] The first one exploited the fueled formation of transient anhydrides, while the others that of transient disulfides.…”

In situ Synthesis of Supramolecular Polymers: Finding the Right Conditions when Combining Covalent and Non‐Covalent Synthesis

“…Transferring this bioinspired synthetic strategy to artificial systems is appealing, since it might provide access to novel structures and functions [4, 5] . This has been showcased in the field of systems chemistry, in which coupling of a cycle of covalent reactions to an assembly process creates systems with transient properties [3, 8, 9–21] . Yet, the number of examples also highlights the pitfalls that come along with a combined covalent/non‐covalent synthesis.…”