A dual enzyme-phosphate hybrid nanoflower for glutamate detection

Abstract

The enzyme hybrid nanoflower has gained interests in biosensors due to their simple synthesis and high efficiency. In this study, glutamate oxidase (GLOX) and horseradish peroxidase (HRP) hybrid nanoflowers (GLOX&HRP-HNFs) were successfully prepared for the detection of glutamic acid (Glu). The effects of the synthesis conditions on the activity of GLOX & HRP-HNFs were investigated. Results revealed that the maximum activity of GLOX&HRP-HNFs was under 4 mM phosphate radical, 2.5 mM MnSO4, 0.04 mg/mL GLOX, and 0.16 mg/mL HRP. After immobilization, no significant differences were observed in optimum pH and temperature values of the GLOX and HRP. The GLOX&HRP-HNFs exhibited higher storage stability and resistance to organic solvents than free GLOX and HRP. Additionally, the GLOX&HRP-HNFs maintained 69% of its primary activity after 6 cycles. More important, the GLOX&HRP-HNFs exhibited a good linear range from 1 to 100 μM (R2 = 0.9979) and a low limit of detection (LOD) of 0.59 μM for glutamate. These results suggest that the GLOX&HRP-HNFs is a promising candidate for applications in biosensing for the detection of glutamate.