The construction of Fe-porphyrin nanozymes with peroxidase-like activity for colorimetric detection of glucose

As a type of nanomaterials with enzyme-mimetic catalytic properties, nanozymes have attracted wide concern in biological detection. H2O2 was the characteristic product of diverse biological reactions, and the quantitative analysis for H2O2 was an important way to detect disease biomarkers, such as acetylcholine, cholesterol, uric acid and glucose. Therefore, there is of great significance for developing a simple and sensitive nanozyme to detect H2O2 and disease biomarkers by combining with corresponding enzyme. In this work, Fe-TCPP MOFs were successfully prepared by the coordination between iron ions and porphyrin ligands (TCPP). In addition, the peroxidase (POD) activity of Fe-TCPP was proved, in detail, Fe-TCPP could catalyze H2O2 to produce ·OH. Herein, glucose oxidase (GOx) was chosen as the model to build cascade reaction by combining Fe-TCPP to detect glucose. The results indicated glucose could be detected by this cascade system selectively and sensitively, and the limit of detection of glucose was achieved to 0.12 μM. Furthermore, a portable hydrogel (Fe-TCPP@GEL) was further established, which encapsulated Fe-TCPP MOFs, GOx and TMB in one system. This functional hydrogel could be applied for colorimetric detection of glucose by coupling with a smartphone easily.