Iron, copper and silver nanoparticles: green synthesis using green and black tea leaves extracts and evaluation of antibacterial, antifungal and aflatoxin B1 adsorption activity

The present study was aimed to account an eco-friendly synthesis of iron (Fe), copper (Cu) and silver (Ag) nanoparticles (NPs) using green tea and black tea leaves extracts. Synthesized NPs were characterized using SEM, FTIR, EDX and UV/Vis spectroscopy techniques. Antibacterial activity of NPs was assessed against methicillin- and vancomycin-resistance Staphylococcus aureus strains. Antifungal activity was investigated against Aspergillus flavus and A. parasiticus fungal species. Adsorbent capability with aflatoxin B1 (AFB1) was also assessed in solution. Ag-NPs showed superior antibacterial/antifungal activities and reduced the aflatoxins production in comparison to Fe-NPs and Cu-NPs. Adsorption capability of all NPs with AFB1 contamination was found in the order of Fe-NPs > Cu-NPs > Ag-NPs. The equilibrium data showed the favorability of Langmuir isotherm with the adsorption capacity (131–139 ng/mg), Cu-NPs (114–118 ng/mg) and Ag-NPs (110–115 ng/mg). Thermodynamic parameters and kinetic studies revealed that adsorption process is spontaneous, endothermic and followed the pseudo-second order. These results suggest that the synthesized NPs could be effectively utilize as an alternative antibacterial/antifungal agent against diseases caused by multiple drug resistant pathogens. In addition, these metal NPs may be utilize as a possible aflatoxins adsorbent in human food and animal feed such as rice, wheat, maize, red chillies and poultry feed.