Glucose oxidase@Cu-hemin metal-organic framework for colorimetric analysis of glucose

The work presents a novel glucose [email protected] metal-organic frameworks ([email protected] Cu-hemin MOFs) with a ball-flower structure as bienzymatic catalysts for detection of glucose. The [email protected] MOFs exhibits great stability as compared with free horseradish peroxidase and GOD toward harsh conditions because the ball-flower-like shell of Cu-hemin MOF effectively protects from GOD. Thus, the [email protected] MOFs can be used in external harsh conditions such as high temperature and acid/base. The [email protected] MOFs is capable of sensitive and selective detection of glucose via peroxidase-like of Cu-hemin MOFs and GOD by using 3,3′,5,5′-tetramethylbenzidine (TMB) as a substrate. Under the existence of glucose, O2 is reduced into H2O2 via [email protected] MOFs. The produced H2O2 as well as Cu-hemin MOFs oxidize TMB into blue oxTMB which shows UV–Vis absorbance at 652. The absorption intensity of oxTMB linearly increases with the increasing concentration of glucose from 0.01 to 1.0 mM with detection limit of 2.8 μM. An integrated agarose hydrogel film (Aga/[email protected] MOF/TMB) sensor is rationally designed for colorimetric detection of glucose. The sensor displays a response range of 30 μM-0.8 mM with a detection limit of 0.01 mM. The result indicates that the Cu-hemin MOFs are an ideal carrier for the encapsulation of enzymes.