Bi-directional feedback controlled transience in Cucurbituril based tandem nanozyme

Life is fueled by multi-enzymatic tandem processes that display unmatched catalytic efficiencies owing to certain features of the biological reactors such as compartmentalization, nano-confinement, and outof-equilibrium dynamics. With an attempt to match such natural catalytic systems, herein, we present a chemoenzymatic pH clock mediated transient assembly of a vesicular nanozyme. Distinct confinement of two catalytically discrete units, Histidine groups on the periphery and hemin in the lipid bilayer, results in an efficient hydrolase-peroxidase tandem catalysis in a temporally controlled fashion. The pH clock, constituted by alkaline TRIS (Tris(hydroxymethyl)aminomethane hydrochloride) buffer (promoter) and glucose oxidase (GOx) catalyzed oxidation of glucose, steers the transience in an asymmetric fashion. Alkaline TRIS buffer enhances the pH of the system and triggers the formation of imine linked Supramolecular Peptide Amphiphiles (SPAs) that further assemble into vesicles. On the other hand, oxidation of glucose produces gluconolactone and H2O2. Gluconolactone hydrolyzes to gluconic acid (deactivator) which dissipates the nanozyme while H2O2 is used in the peroxidase catalysis. Thus, the bidirectional feedback from the fuel not only regulates the existence of the transient state but also controls the activity of the assembly. The transiently assembled nanozyme protected the activity of the catalytic units, displayed substrate specificity and catalytic reproducibility over multiple fueling cycles. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This article presents a transient assembly of a vesicular nanozyme mediated by a chemoenzymatic pH clock, which achieves efficient hydrolase-peroxidase tandem catalysis through distinct confinement effects. The assembly is controlled by a pH clock composed of alkaline TRIS buffer and glucose oxidase (GOx) catalyzed oxidation of glucose.