AUTHOR=Ullah Sami , Khalid Rimsha , Rehman Muhammad F. , Irfan Muhammad I. , Abbas Azhar , Alhoshani Ali , Anwar Farooq , Amin Hatem M. A. 

TITLE=Biosynthesis of phyto-functionalized silver nanoparticles using olive fruit extract and evaluation of their antibacterial and antioxidant properties

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1202252

DOI=10.3389/fchem.2023.1202252

ISSN=2296-2646

ABSTRACT=Green synthesis of nanomaterials is of utmost interest as it offers an eco-friendly approach over chemical synthetic routes. However, reported biosynthesis methods are often time-consuming and require heating or mechanical stirring. The current study reports a facile one-pot biosynthesis of silver nanoparticles (AgNPs) mediated by olive fruit extract (OFE) and sunlight irradiation of only 20 s. OFE acts as both reducing and capping agent for the formation of OFE-capped AgNPs (AgNPs@OFE). The as-synthesized NPs were systematically characterized by UV-Vis spectrometry, Fourier transform-infra red (FTIR) spectroscopy, scanning electrochemical microscopy along with energy-dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), dynamic light scattering (DLS) and cyclic voltammetry. SEM images confirmed the successful formation of monodispersed spherical AgNPs@OFE of about 77 nm. FTIR suggested the involvement of functional groups of phytochemicals from the OFE in the capping and reduction of Ag+ to Ag. The particles revealed excellent colloidal stability as evidenced from the high zeta potential ZP value (–40 mV). Interestingly, using the disk diffusion method, AgNPs@OFE revealed higher inhibition efficiency against Gram-negative bacteria (Escherichia coli, Klebsiella oxytoca and extensively drug-resistant (XDR) Salmonella typhi) than Gram-positive bacteria (Staphylococcus aureus) with Escherichia coli at highest with inhibition zone of 27 mm. In addition, AgNPs@OFE exhibited potent antioxidant scavenging potential against H2O2 at most, followed by DPPH, O2– and OH– free radicals. Overall, OFE can be considered as an effective source for the sustainable production of stable AgNPs with potential antioxidant and antibacterial activities for biomedical applications.