Enhanced activity of enzymes encapsulated in spheres metal azolate framework-7 with defects.

Abstract

Developing metal-organic frameworks (MOFs) with specific structures is critical for improving the activity of embedded enzymes, and defects may be one of the effective methods. Several methods have been demonstrated to be effective in creating defects in MOFs, including post-synthetic treatments, the use of acid as a modulator, and the use of ordinary or thermally sensitive linkers. However, these methods necessitate the utilization of additional substances. Metal azolate framework-7 (MAF-7) is a kind of MOF that was formed by the coordination of Zn²⁺ with 3-methyl-1,2,4-triazole (Hmtz). This paper presents a method for the preparation of defect MAF-7 by changing the sequence of reactants without the introduction of additional substances. The defects were characterized by a range of techniques, including scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, and powder X-ray diffraction. The activity of microcystinase A (MlrA) encapsulated in defective MAF-7 (CMlrA@DMAF-7) was found to be significantly increased in comparison to non-porous MAF-7 (NMAF-7), and was largely unaffected by alterations in synthesis conditions. It is also noteworthy that lysozyme (LZ) and horseradish peroxidase (HRP), which are commonly used in industry, also demonstrated enhanced activity when encapsulated in DMAF-7. It was therefore anticipated that modifying the sequence of reactant addition would be a straightforward and simple method of introducing defects into MAF-7, thereby improving enzyme utilization.