Chemically Fueled Block Copolymer Self-Assembly into Transient Nanoreactors

Abstract

In chemically fueled supramolecular materials, molecular self-assembly is coupled to a fuel-driven chemical reaction cycle. The fuel-dependence makes the material dynamic and endows it with exciting properties like adaptivity and autonomy. In contrast to the large work on the self-assembly of small molecules, we herein designed a diblock copolymer, which self assembles into transient micelles when coupled to a fuel-driven chemical reaction cycle. Moreover, we used these transient block copolymer micelles to locally increase the concentration of hydrophobic reagents and thereby function as a transient nanoreactor.

Endergonic synthesis driven by chemical fuelling

“…https://doi.org/10.1038/s44160-024-00493-w nonequilibrium and systems chemistry 40,[48][49][50][51][52] , and we have previously proposed 3 that such a fuelling reaction could be suitable for driving coupled reactions out-of-equilibrium.…”

“…https://doi.org/10.1038/s44160-024-00493-w sequence-specific synthesis 33,34,58,59 , dissipative materials 40,48,49,52,60,61 and endergonic supramolecular structures [17][18][19] . The simplicity of the reactants and fuelling cycle of 5 provides a minimalist demonstration of chemically fuelled ratcheted synthesis that aids its understanding in biology and potential utility in synthesis.…”

“…Transient tethering of the two carboxylic acids of the biaryl catalyst to form an anhydride enables atropisomer interconversion, with kinetic asymmetry 10,[13][14][15][16][17][18][19][20] in the fuelling cycle (generated by the use of a chiral carbodiimide and chiral hydrolysis promoter) driving the endergonic deracemization 35 . We hypothesized that similar transient tethering could be used to bring a diene and dienophile into close proximity 40 , promoting an otherwise endergonic Diels-Alder reaction by organizing the reactants for the cycloaddition and substantially increasing the effective concentration. In an energy ratchet mechanism (which cyclically switches the relative heights and depths of energy minima and maxima 11 ) this could produce a power stroke that thermodynamically favoured the Diels-Alder reaction in the tethered state; in an information ratchet mechanism 11 , any kinetic asymmetry in the rates that the starting materials and product react with the fuel (and/or waste) would drive the Diels-Alder:retro-Diels-Alder ratio away from the equilibrium value 3,10,20 .…”

Design rules for reciprocal coupling in chemically fueled assembly

“…15,16 These chemical reaction cycles activate and deactivate molecules for assembly into, e.g., micelles, 9,17,18 vesicles, 19 droplets, 12,20 colloids, 8,11 nano-or microparticle clusters, 21,22 and bers. 11,14,16 Moreover, molecular assemblies that catalyze chemical reactions are well known and include micelles that catalyze Diels-Alder reactions, 23 membrane-less organelles catalyze aldol reactions, 24 catalytic bers and nanotubes catalyze aldol reactions, 25 ester hydrolysis, 26,27 Diels-Alder reactions. 28 However, systems where the two concepts are combined, i.e., a reaction cycle that regulates assembly and the assembly that regulates the reaction cycle, are underexplored.…”

Transient and Dissipative Host–Guest Hydrogels Regulated by Consumption of a Reactive Chemical Fuel

“…Mechanistic insights into the formation and lifetime of transient and dissipative self-assembling systems have also been gleaned from these carbodiimidefueled reaction cycles, along with efforts to exploit the transient and tunable nature of these materials for emergent applications. [11][12][13][14][15][16] Beyond using chemical reactions to directly modify the chemical identity of a species leading to dissipative selfassembly, fuels may instead be integrated indirectly as cues for transient material formation. Examples of this approach include monomers that bind adenosine triphosphate (ATP) to self-assemble, disassembling once ATP is limiting.…”