A charge-assisted hydrogen-bonded organic framework as a host platform for enzyme immobilization and robust biocatalysis

Abstract

In situ encapsulation of enzymes into hydrogen-bonded organic frameworks (HOFs) offers a promising strategy to enhance enzyme durability and activity recovery in biocatalysis. In this study, we report the immobilization and stabilization of catalase (CAT) and α-amylase (α-Amy) using a novel charge-assisted HOF, TNU-14. This HOF is constructed from tiramidinium and tricarboxylate building blocks under ambient conditions. Benefiting from the electrostatic interactions between the negatively charged enzyme surfaces and the positively charged tiramidinium units, the TNU-14 exoskeleton forms around the enzymes within 15 minutes. As a result, TNU-14 effectively protects the enzymes from degradation while maintaining their activity under harsh chemical and physical conditions, including acidic or alkaline environments, proteolytic enzyme trypsin, chaotropic agent urea, high temperatures, and through at least ten catalysis/filtration cycles. This study represents the first demonstration of a charge-assisted HOF scaffold assembled from trigonal building blocks for enzyme immobilization, paving the way for developing a toolset for enzyme and protein carriers.