Glucose oxidase immobilization on Hemin@PCN-222 (Mn): Integrated biomimetic and bioenzyme activities in cascade catalytic process

On accounting of the structure advantages of MOFs in the enzyme mimics and enzyme immobilization, in this work, the Hemin@PCN-222 (Mn) is constructed through an in-situ hydrothermal route by covalently bonded the –COOH of Hemin with the Zr(IV) of PCN-222 (Mn). With the help of the synergistic effects, the resulting Hemin@PCN-222 (Mn) represents excellent peroxidase-like activities in comparison with the single Hemin and PCN-222 (Mn) with a special enzyme activity of 6.71 U mg−1. The Hemin@PCN-222 (Mn) was then employed as a carrier to immobilize the glucose oxidase (GOx), the immobilization conditions were optimized. Based on that, the optimized GOx@hemin@PCN-222 (Mn) was applied in the following cascade reaction: the glucose oxidation in the presence of oxygen catalyzed by the immobilized GOx firstly, and then the produced H2O2 worked as an oxidant to oxidize ABTS. The quantity of produced ABTS+ was monitored to assess the catalytic efficiency, and the contrast experiments were conducted over the mixture of the natural GOx and HRP. The above cascade process could also be used to detect the glucose, and the detection limit is determined. The high efficiency and the stability of the resulting GOx@hemin@PCN-222 (Mn) highlights the prospect applications of the MOFs-based enzyme mimics in the bio-catalysis and biosensing.