Synthesis of Ag nanoparticles supported on magnetic halloysite nanozyme for detection of H2O2 in milk and serum

In the present study, Ag nanoparticles modified Fe3O4 anchored on roughened halloysite nanotubes nanocomposites (Ag@Fe3O4/RHNT) with high peroxidase-like activity and good magnetism was fabricated, and accordingly, an efficient and sensitive colorimetric sensing platform was established for the detection of H2O2. Firstly, halloysite nanotubes was pre-treated and then Fe3O4 nanoparticles were uniformly deposited on the external surface of RHNTs. Finally, Ag nanoparticles were grown onto Fe3O4/RHNT by in-situ reduction method. All characterization results confirmed the successful synthesis of Ag@Fe3O4/RHNT. The resultant Ag-Fe3O4 RNHTs exhibited satisfied catalytic activity to the oxidation of TMB (4,4'-Diamino-3,3′, 5,5′-tetramethylbiphenyl) in the presence of H2O2, and the catalytic process is accompanied with the color changed from colorless to bule. Thus, a sensitive colorimetric sensor for detection of H2O2 was developed based on Ag@Fe3O4/RHNT nanocomposites. And the optimal reaction temperature and pH were determined to be 55 °C and 4, respectively. H2O2 can be detected in the range of 10–100 μM with the detection limit of 0.7 μM. In conclusion, we established an efficient colorimetric sensing system for H2O2, and applied it to detect H2O2 in milk and serum.