Pulsating Polymer Micelles via ATP-Fueled Dissipative Self-Assembly

Abstract

Energy dissipation underlies dynamic behaviors of the life system. This principle of biology is explicit, but its in vitro mimic is very challenging. Here we use an energy-dissipative self-assembly pathway to create a life-like polymer micellar system that can do periodic and self-adaptive pulsating motion fueled by cell energy currency, adenosine triphosphate (ATP). Such a micelle expansion−contraction behavior relies on transient supramolecular interactions between the micelle and ATP fuel. The micelles capturing ATPs will deviate away from the thermodynamic equilibrium state, driving a continuous micellar expansion that temporarily breaks the amphiphilic balance, until a competing ATP hydrolysis consumes energy to result in an opposing micellar contraction. As long as ATP energy is supplied to keep the system in out-of-equilibrium, this reciprocating process can be sustained, and the ATP level can orchestrate the rhythm and amplitude of nanoparticulate pulsation. The man-made assemblies provide a model for imitating biologically time-dependent self-assembly and periodic nanocarriers for programmed drug delivery.

Energy consumption in chemical fuel-driven self-assembly

“…In the absence of reported kinetic parameters for all reaction steps in published examples of self-assembling systems relying on chemical fuel consumption, 11,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] it is impossible to certify in an unambiguous manner whether these systems exploit a chemically-driven information ratchet mechanism. Such an analysis is further hampered by the fact that most examples rely on the batch-wise addition of fuel, in which high-energy species may indeed be transiently observed, but not necessarily because of asymmetric energy consumption.…”

Substrate‐Induced Self‐Assembly of Cooperative Catalysts

“…Synthetic chemical‐fuel driven self‐assembly processes have been reported that also rely on noncovalent interactions between the building blocks and a chemical fuel . However, while most cases allude to similarities with microtubule formation or related biological dissipative processes, it turns out that in all the cases reported so far, a fundamentally different mechanism is operative (Figure b) . Contrary to what happens in Nature, energy dissipation, intended as the release of energy stored in the chemical fuel, is not catalysed by the building blocks, but rather by external elements such as an enzyme.…”

Applications of Dissipative Supramolecular Materials with a Tunable Lifetime

“…Moreover, both the time when the material is released as well as the sequence of the released dyes can be predetermined by the users. These studies, as well as other from the field, show the exciting possibilities of dissipative supramolecular materials as drug delivery vehicles or other biomaterials in the future.…”