Introduction of Cascade Biocatalysis Systems into Metal-Organic Aerogel Nanostructures for Colorimetric Sensing of Glucose

Exploitation of metal-organic aerogels (MOAs) with porous properties for the immobilization of enzymes should have significant applications. A facile method for the synthesis of MOAs using poly(propylene glycol) (PPG) as a gelling agent is presented in this paper. In particular, a porous UiO-66-NH2 aerogel containing an iron porphyrin unit has been synthesized using PPG. The MOA not only displays high mesopores for glucose oxidase (GOx) immobilization but also has the unit of iron porphyrin as a peroxidase mimick for a cascade reaction. After the immobilization of GOx, the composite was used for the colorimetric sensing of glucose, exhibiting a good linear range, a low limit of detection, and excellent selectivity. Furthermore, the MOA-immobilized GOx shows enhanced stability against organic solutions and longer storage stability at room temperature, attributed to the protective effect of the UiO-66-NH2 aerogel. This MOA with porous properties should provide an extended platform for enzyme immobilization and open up a route for the development of biocatalyst systems for advanced applications in biosensing, bioindustrial catalysis, and biofuel cells.