Utilization of tea resources with the production of superparamagnetic biogenic iron oxide nanoparticles and an assessment of their antioxidant activities

An eco-friendly, low toxic and facile synthetic approach was employed to produce superparamagnetic biogenic iron oxide nanoparticles (SPBIONs) using an aqueous extract of tea-pruning waste as a reducing agent under alkaline conditions. As-biosynthesized SPBIONs were extensively characterized by various analytical tools. For instance, XRD pattern showed crystallinity and FTIR spectra revealed the presence of bioactive molecules required for the reduction of iron oxide ions. AFM and FESEM-EDX images showed agglomerated spherical shape with strong signals of iron metallic ions. The average crystallite sizes of SPBIONs were found to be 20e35 nm by HRTEM analysis. Zeta potential analysis confirmed that the surface charge of the green synthesized SPBIONs was highly negative (-25.2 mV) and stable. TGA curve reported a weight loss of 14%, which occurred in SPBIONs over temperatures ranging from 50 degrees C to 950 degrees C due to the removal of water molecules and volatile compounds. VSM analysis revealed that SPBIONs exhibited superparamagnetic properties with a high-saturation magnetization value of 11 emu/g. In addition, the antioxidant property of SPBIONs was investigated with 1,1-Diphenyl-2-picrylhydrazyl (DPPH), a free radical assay, and it was seen that 70 mg/mL (IC50) of SPBIONs was able to neutralize the generation of free radicals and oxidative stress. The present study successfully demonstrated that utilization of tea resources for the production of SPBIONs with superparamagnetic and antioxidant properties might be used to design antioxidant agents and other biomedical applications. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

In this study, superparamagnetic biogenic iron oxide nanoparticles (SPBIONs) were successfully synthesized using an eco-friendly and low toxic approach with aqueous extract of tea-pruning waste as the reducing agent under alkaline conditions. The SPBIONs exhibited stable surface charge, average crystallite size of 20-35 nm, and high saturation magnetization value of 11 emu/g. Furthermore, the SPBIONs showed antioxidant properties by neutralizing the generation of free radicals and oxidative stress.