pH clock instructed transient supramolecular peptide amphiphile and its vesicular assembly

Abstract

A pH clock directed transient supramolecular peptide amphiphile and its vesicular assembly using ternary complexation of cucurbit[8]uril is displayed.

Guest Exchange by a Partial Energy Ratchet in Water

“…[30,31] Cucurbit[n]urils (CB-[n]) [32][33][34][35][36] have since then been used in ap lethora of applications in water, [37][38][39][40][41][42] including molecular machines [43][44][45] or more recently systems working away from equilibrium. [46][47][48] In about 20 years,k ey results were obtained by the teams of Isaacs,K im, Kaifer and others illustrating the relevance of using CB[n]for self-sorting, [49][50][51][52] stimuli-responsive systems, [42,45,[53][54][55] or for kinetic versus thermodynamic control. [56,57] In 2002, [58,59] the inclusion of methyl-viologen in CB [7] was reported opening an ew prolific interface.L ater, pH was shown to trigger shuttling of CB [7] on and off over av iologen axle featuring carboxylate groups.…”

Programming properties of transient hydrogels by an enzymatic reaction

“…To induce a pH change, the autocatalytic reaction between urea and urease was developed by Taylor et al [55][56][57] and also used by Walther et al 58,59 and other research groups. 16,[60][61][62][63] Under aqueous conditions, urea reacts with urease to produce ammonia, which is responsible for the increase of the pH of the medium. [64][65][66][67][68] The reaction itself is highly dependent on the initial reaction conditions such as pH and the reagent concentrations, 57,64,65 which enables us to exercise precise control over the rate of pH change and subsequent transitions between the energy states.…”

“…In comparison, natural self-assembled structures and processes such as microtubule formation, cell division, replication, formation of actin filaments, and signal transduction are energetically up-hill processes and so require a continuous source of energy input to maintain the assembled structures. 10,[15][16][17][18][19][20] Such assemblies are kinetically controlled and are classified as out-of-equilibrium assemblies where the functional efficiency of the assembly state is governed by the assembly pathway. Such out-of-equilibrium kinetics create supramolecular assemblies of finite lifetimes which are referred to as transient self-assembled systems.…”

Guest Exchange by a Partial Energy Ratchet in Water

“…In 2000, the chemistry of the synthetic macrocycle cucurbit[6]uril dramatically expanded after the reports of lower and higher size homologues [30, 31] . Cucurbit[ n ]urils (CB[ n ]) [32–36] have since then been used in a plethora of applications in water, [37–42] including molecular machines [43–45] or more recently systems working away from equilibrium [46–48] . In about 20 years, key results were obtained by the teams of Isaacs, Kim, Kaifer and others illustrating the relevance of using CB[ n ] for self‐sorting, [49–52] stimuli‐responsive systems, [42, 45, 53–55] or for kinetic versus thermodynamic control [56, 57] .…”