Hierarchically Porous and Water-Tolerant Metal–Organic Frameworks for Enzyme Encapsulation

Abstract

Metal−organic frameworks (MOFs) for in situ enzyme encapsulation commonly possess weak metal−ligand coordination bonds and rather small pores, which are instable in aqueous solution and present rather high diffusion resistance of reactants. Herein, we prepare a type of hierarchically porous and water-tolerant MOFs through a facile polyphenol treatment method for enzyme encapsulation. In brief, enzymes are first in situ encapsulated in a zeolitic imidazolate framework-8 (ZIF-8) through coprecipitation of enzymes, zinc ions (Zn 2+ ), and 2-imidazole molecules (2-MI). Then, tannic acid (TA, a typical polyphenol) is introduced to functionalize the surface and etch the void of ZIF-8, acquiring the biocatalyst termed as E@ZIF-8@ZnTA. The hierarchically porous structure would accelerate the diffusion process of reactants, whereas the Zn-O bond in a TA-Zn nanocoating would improve the structural stability against water corrosion compared to ZIF-8. Taking glucose oxidase (GOD) as a model enzyme for the catalytic conversion of β-D-glucose, the

A Systematic Study of the Stability of Enzyme/Zeolitic Imidazolate Framework‐8 Composites in Various Biologically Relevant Solutions

“…SEM showed that GOx@ZIF‐8 was smaller than ALP@ZIF‐8 in particle size. The shape of these composites was similar to those reported in some studies [15,18,24] but different from the polyhedral shape reported in others [5,7,8] . The variations in morphology ( e. g .…”

“…It is therefore likely that the susceptibility of enzyme@ZIF‐8 composites to these chemical agents is not greatly affected by the exact nature of the proteins in the composites. However, the morphology, particle size and crystallinity of the enzyme@ZIF‐8 composites do appear to vary among studies even under similar synthesis conditions [5,7,8,15,18,24] and surface area of lipase@ZIF‐8 is affected by the Zn 2+ /2‐MI molar ratio during synthesis [61] . It is likely that these properties ( i. e .…”

Hierarchically Porous Biocatalytic MOF Microreactor as a Versatile Platform towards Enhanced Multienzyme and Cofactor‐Dependent Biocatalysis

“…[21,38] Compared to the previous methods, [31][32][33][34][35][36] this method is facile,l ow-cost, and less-time consuming.Importantly,itiscompatible with most substrates because of the high binding affinity of TA to diverse surfaces, which has shown potential as ah ost platform for enzyme immobilization. [39] However, the complex interfacial interactions of enzyme and hierarchically porous MOFs are rarely revealed. Very recently,T sung and co-workers probed the interactions between encapsulated enzyme and hollow-shell MOF matrices.…”

Biocatalytic Metal–Organic Frameworks: Prospects Beyond Bioprotective Porous Matrices

“…[83] Electrostatic interaction between GOx/PCN-222(Fe) GOx/PCN-222(Fe) stable at pH 27. [84] Surface coating Tannic acid coating on MOFs ZIF-8@ZnTA remained stable at pH 5.0 for 1 h. [86] Silanes or coordination complexes (TA and Fe 3+ ) SiO 2 @catalase/ZIF-8 and Fe 3+ -TA@catalase/ZIF-8 remained stable at pH 3.0 for 60 min. [87] Defect engineering Inserting carboxylate or phosphate-rich biomacromolecules PGA@ZIF-L, DNA@ZIF-L and catlase@ZIF-L remained stable at pH 5 for 3 h. [88] Synergistic properties…”