Kinetic traps in chemically fueled self-assembly and how to overcome them.

Abstract

Nature uses dynamic, molecular self-assembly to create cellular architectures that adapt to their environment. For example, a guanosine triphosphate (GTP)-driven reaction cycle activates and deactivates tubulin for assembly into microtubules and disassembly. Inspired by dynamic self-assembly in biology, multiple studies have developed synthetic analogs of assemblies regulated by chemical chemically fueled reaction cycles. A challenge in most of these studies is that molecules assemble upon activation but do not disassemble upon deactivation. In other words, they remain kinetically trapped, and the resulting assemblies are not dynamic. In this work, we show how molecular design dictates the tendency of deactivated molecules to remain trapped in the assembled state. We also show how molecular design can be used to tune the dynamics of the reaction cycle. Our work should result in chemically fueled assemblies that are truly dynamic in that dis-assembly immediately follows deactivation.

A chemically fueled supramolecular glue for self-healing gels

“…We hypothesize that either the product assembles and does not deactivate after assembly resulting in a static network, or, the product is deactivated in the fiber and does not disassemble before its reactivation in the fiber, which also results in a static fiber network. In line with previous work on similar peptides, 40,42 a 1 H-NMR-study showed that most of the peptides, be it in the precursor or product state, reside in the assembled state ( vide infra ). Thus, the precursor remains kinetically trapped within the fibers after deactivation and is reactivated before it can disassemble (Fig.…”

Carbodiimide‐Fueled Assembly of π‐Conjugated Peptides Regulated by Electrostatic Interactions**

“…[23] However, we found that the EDC-triggered assemblies of DVV-4T are stable at room temperature (Figure S16), suggesting the influence of π-conjugated core on the stability of the assemblies formed upon the addition of EDC. In addition, the impeded disassembly process could be 10/21 attributed to the increased aspartic acid's apparent pKa after aggregate formation, [28,34,47] along with the impact of the hydrophobic π-conjugated motifs. [48] Considering that the peptidic monomers might form kinetically trapped assembly structures, we explored the effect of increasing the solution temperature to accelerate the hydrolysis of anhydride groups and the disassembly process.…”

Methods of changing low molecular weight gel properties through gelation kinetics

“…[85][86][87] As such, changing the pH of the pre-gelled solution can result in a change in the self-assembly due to differences in solubility. [88][89][90] Therefore, this is another potential way to tune the properties of the resulting hydrogels.…”