Glutamate oxidase-integrated biomimetic Fe3O4 hybrids as cascade nanozymes for glutamate detection

Herein, a new nanozyme/natural enzyme hybrid biosensor was established for ultrasensitive L-glutamic acid (L-Glu) detection. The Fe3O4 nanoparticles with peroxidase-like activity and stability was used as a nanozyme and carrier for immobilizing L-Glutamate oxidase (GLOD) through Schiffff base reaction to construct a chem-enzyme cascade detector. The resultant Fe3O4-GOLD exhibited a wide linear range (10-500 mM) and a low detection limit of 6.03 mM for L-Glu detection. Furthermore, the Fe3O4-GOLD exhibited excellent pH stability, thermal stability, reusability and storage stability. After repeated nine cycles, Fe3O4-GOLD still retained 70% of its initial activity. Meanwhile, Fe3O4-GOLD maintained 50% of its initial activity after storage for 20 days, while free GLOD only retained 20% of its initial activity. This strategy of integrating biomimetic Fe3O4 and natural enzymes for cascade catalysis makes it possible to design an efficient and stable chemo-enzyme composite catalysts, which are promising for applications in biosensing and biomimetic catalysis.(c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

A new nanozyme/natural enzyme hybrid biosensor was developed for ultrasensitive detection of L-glutamic acid (L-Glu). Fe3O4 nanoparticles with peroxidase-like activity and stability were used as a nanozyme and carrier to immobilize L-Glutamate oxidase (GLOD), forming a chem-enzyme cascade detector. The Fe3O4-GOLD showed a wide linear range and low detection limit, as well as excellent stability.