Biogenic Synthesis of Gold Nano-Particles Using Origanum Syriacum Extract for catalytical, antioxidant and quenching applications

Abstract

The interest in using nano-particles (NPs) has increased in recent years due to the wide range of applications. Gold nano-particles (AuNPs) are metallic NPs with a wide variety of applications in several scientific and technological domains that is gaining popularity in demand recently.

To fulfill this, an in-depth study of optimizing synthesis techniques for AuNPs is required. Among the various methods reported for the synthesis of AuNPs including chemical, physical, and biological (green) methods; biogenic synthesis using plant extract has been found to be the fastest, easiest, most cost-effective, and environmentally friendly method. The antibacterial, analytical, antioxidant, anticancer, and catalytic capabilities of AuNPs generated from plant extract have demonstrated remarkable results in a variety of biological applications.

In this thesis for biosynthesizing and optimizing AuNPs; Origanum syriacum plant extract is used. Formed AuNPs have been characterized using several spectroscopic and microscopic techniques such as UV-Visible, DLS, SEM, and EDX. The formed NPs then have been used as catalysts for the reduction of different organic dyes, and recycled for three times to catalyze the reduction of Congo red. Furthermore, the AuNPs generated exhibited notable capabilities in scavenging free radicals, demonstrated by a substantial 62.1% inhibition of DPPH only using 900 µl of AuNPs. Additionally, the impact of AuNPs on the fluorescence intensity of Rhodamine B was investigated. It was observed that the most significant quenching effect occurred with 200 µl of AuNPs. The quenching was not interfered by uric acid, ascorbic acid, glucose, ATP, phenol, and melamine.