Synthesis and characterization of glucose oxidase bimetallic hybrid magnetic nanoflowers for a sensitive glucose biosensor and an effective antibacterial agent

Abstract

Herein, glucose oxidase was immobilized into bimetallic (Cu²⁺, Zn²⁺) hybrid magnetic nanoflowers (GOx-mcNFs) to perform as a more stable glucose biosensor and antibacterial material. Morphological characterizations of GOx-mcNFs verified the construction of nanoflowers through metal ions-GOx coordination. The encapsulation yield was obtained as 93.5 %, where the activity recovery was 650.3 %. Magnetic nanoparticles also enhanced the peroxidase-like activity of metal-phosphates and caused GOx-mcNFs to show excellent peroxidase-like properties with the apparent K_m values of 0.19 mM and 0.267 mM for H2O2 and TMB, respectively. Thermodynamic studies revealed a 16.5 kJ mol⁻¹ higher activation energy of denaturation for GOx-mcNFs over the free GOx. The reusability of GOx-mcNF was confirmed by maintaining 70.5 % of its initial activity until the eighth cycle. A limit of detection as 0.7 µM with a wide linear range (0–1000 µM) and the recovery rate of human serum glucose as 97.02–105.9 % were attained. Furthermore, GOx-mcNFs displayed an antibacterial effect due to the generation of ROS by peroxidase-like nanozymes. In vitro antibacterial assays displayed inactivation rates of 99.6 % and 98.8 % against S.aureus and E.coli with 75 μg mL⁻¹ and 750 μg mL⁻¹ of GOx-mcNFs, respectively. Consequently, bi-functional GOx-mcNF provides a promising strategy for glucose biosensing and antibacterial applications.