Biosynthesis of bimetallic Au-Ag nanoparticles using Abrus precatorius seed Extract: Analysis of photocatalytic, cytotoxic, and antibacterial activities

Abstract

The present investigation aims to examine the bio-route preparation of gold-silver bimetallic nanoparticles using an aqueous seed extract of the Abrus precatorius plant. The bio-synthesized gold-silver bimetallic nanoparticles (AP-Au-Ag NPs) were characterized by various spectroscopic techniques. The surface plasmon resonance (SPR) peak at 555 nm for Au, 433 nm for Ag, and 546 nm for the Au-Ag alloy indicates that bimetallic NPs have been formed. FTIR data provided evidence of functional groups such as OH, CO, and NH2 (proteins, flavonoids, and carbohydrates). When making a bimetallic Au-Ag alloy, carbohydrates are useful as a capping agent and proteins as a reducing agent. The AP-Au-Ag NPs’ stability was assessed by looking at their negative zeta potential value of −21.5 mV. The spherical-shaped crystalline alloy AP-Au-Ag NPs was produced with an average particle size of 10 nm. The TEM images verified the presence of polydispersity in the AP-Au-Ag NPs. The synthesized alloy nanoparticles have a potential cytotoxic effect against MCF-7 cancer cell lines with an IC50 value of 25 ± 1.5 μg/mL and the AP-Au-Ag NPs were found to be a good antibacterial agent against gram-positive and gram-negative bacteria. During visible light photocatalysis, ciprofloxacin was not removed after 60 min of exposure when employing materials made of a pure monometallic nanoparticle. However, the use of bi-metallic nanoparticles made of gold and silver resulted in the breakdown of over 90% of the ciprofloxacin into minerals. The produced bi-metallic nanoparticles, composed of Au-Ag showed exceptional catalytic efficiency. The gold-silver alloyed nanoparticles showed the most promise and efficiency when compared to others.