Green synthesis, characterization and electrochemical biosensor application of Fe3O4-Au core-shell nanoparticles / Elisa Rasouli

Elisa , Rasouli (2021) Green synthesis, characterization and electrochemical biosensor application of Fe3O4-Au core-shell nanoparticles / Elisa Rasouli. PhD thesis, Universiti Malaya.

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Abstract

In this study, Fe3O4 nanoparticle (NP) and core-shell Fe3O4-Au NP have been synthesized using natural honey as a green synthesis method. It was found that honey is an effective reducing agent and stabilizer in producing NPs. The particle size of the synthesized material can be controlled by varying the concentration of honey. The particle size could be controlled below 10 nm. The NPs were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray (EDX) analysis, transmission electron microscopy (TEM), selected area electron diffraction (SAED) analysis, X-Ray diffraction (XRD) analysis, ultraviolet-visible spectrophotometer (UVVis) analysis, Fourier transformed infrared spectroscopy (FTIR) analysis, vibrating sample magnetometry (VSM) analysis and cytotoxicity test analysis to investigate the surface morphology, chemical composition, functional group, magnetic properties and toxicity. The TEM image of Fe3O4 NPs showed that particle size decreased from 3.21 nm to 2.22 nm with increasing honey content from 0.5% to 3.0% (w / v) respectively, and increased from 3.21 nm to 4.11 nm in Fe3O4 NPs and Fe3O4 -Au NP (by ratio molar 1:1), after being coated with a gold shell. VSM results revealed the superparamagnetic behavior of both Fe3O4 NPs and Fe3O4-Au NPs, with a decrease in the saturated magnetization from 23.78 emu g- 1 for Fe3O4 NPs to 16.98 emu g- 1 for NP Fe3O4-Au (with a ratio of 1: 1), which is assigned to the formation of gold shells. The FESEM analysis shows that the synthesized NPs possesses a spherical structure, which increases the surface area and provides an ideal environment for sensor applications. The presence of gold from the EDX analysis, SAED analysis and UV-Vis analysis demonstrated the successful gold shell formation on the surface of Fe3O4 - NPs.

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