Biogenic Synthesis of Iron Oxide and Silver Nanoparticles for Dye Degradation and Wound Dressing Applications

Abstract

Green methods for the synthesis of nanoparticles (NPs) have lot of advantages over chemical and physical synthesis methods. These are cheap, simple, environment friendly, reliable and facile. In this research work we report a facile method for the synthesis of iron oxide and silver NPs from the fruit extract of Diospyros lotus. Two different solvents were used for the extraction of biomolecules from the Diospyros lotus i.e. extraction of biomolecules in organic solvent and extraction of biomolecules in water. The effect of both extracts on the reduction of precursor salts was studied. The organic extract was efficient in the reduction of precursor salt than aqueous extract. The synthesized NPs were characterized by UV-Visible spectrophotometer, Infrared spectrophotometer (FTIR), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) technique. FTIR analysis confirmed the presence of proteins, vitamins and reducing sugars in the fruit extract of Diospyros lotus. These biomolecules could be responsible for the reduction and capping of iron oxide and silver NPs, SEM confirmed that particles are of spherical shape with average particle size of 16 to 24 nm for iron oxide and silver NPs. The iron oxide particles possess excellent catalytic activity and degraded dye up to 91 % while silver NPs were found to possess excellent antimicrobial activity. Iron oxide NPs prepared through organic extract showed more catalytic activity for degradation while silver NPs prepared through the same extract has also demonstrated better antimicrobial activity compared to such NPs prepared through aqueous extract. The PVA/Starch hydrogel membrane incorporating Ag NPs was also prepared where XRD and FTIR results confirmed the crosslinking of starch and PVA increasing the mechanical strength compared to pure polymers hydrogel membrane. Additionally, effect of the concentration of silver NPs on the physical as well as antimicrobial properties of the prepared hydrogel membrane was also studied. It was observed that with increasing concentration of silver NPs, mechanical strength decreases but swelling property and water retention capacity was found to increase. The membrane was found to possess excellent antimicrobial property and hence can be used for wound dressing application.