Colorimetric detection of glucose based on ficin with peroxidase-like activity

In this work, we developed a colorimetric biosensing system for glucose detection by coupling the peroxidase-like of ficin and the glucose oxidase (GOx). GOx can catalyze the oxidation of glucose to produce H 2 O 2 , then, ficin catalyzes the oxidation of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 to produce a blue color reaction. The present sensing system showed a linear response toward glucose detection over range of 2.0–100   μM with a detection limit of 0.5   μM. This system is simple, low cost, highly sensitive and selective for glucose detection, and was also applied to measuring glucose in human serum. Furthermore, in order to expand the application of ficin in biological sensing, we immobilized ficin onto the SiO 2 @Fe 3 O 4 NPs, which exhibited the merits of recycling as well as allowing the repeated detection of glucose. Thus it may provide great potential applications in biomedicine, biotechnology and environmental chemistry .