Bioinspired synthesis of Ag/AgCl nanoparticles from Aganonerion Polymorphum leaves: Boosted antibacterial potential

Abstract

The use of plant extracts (mainly polyphenols) as both reducing and stabilizing agents has opened up new scopes in AgNPs biosynthesis. A lack of comprehensive studies on the possibility of Aganonerion Polymorphum (AP) leaves extract prompts an updated synthesis of Ag/AgCl nanoparticles, thanks to the rich source of chlorine in the AP leaves extract, to illuminate the positive effect of AgCl in antibacterial systems. Ag/AgCl nanoparticles were efficiently synthesized using AP leaf extract, serving as both a natural reducing and stabilizing agent. The highest concentrations of polyphenols (2.55 mg/g) and ascorbic acid (2.89 µg/mL) were extracted under optimal conditions (at 70°C for 1.5 hours), acting as the phytochemicals for metal ion reduction to form Ag/AgCl nanoparticles under sunlight, observed by absorbance bands at the wavelength of 400 - 500nm. XRD showed a highly crystalline face-centered cubic structure of Ag and AgCl, and EDX indicated the presence of Ag and Cl. TEM revealed spheres with a nanosize of 15 - 20nm. The zeta potential confirmed the long-term stability of the Ag/AgCl in aqueous solution (-8.7mV). As-prepared Ag/AgCl demonstrated an excellent antibacterial ability against five bacteria, as indicated by their inhibition zone (average diameter > 9.3mm) and minimum inhibitory concentration (MIC, 16.6 μg/mL). This study proposes a green and sustainable strategy for synthesizing Ag/AgCl nanoparticles, employing AP leaf extract as a natural reducing and stabilizing agent under ambient temperature conditions. The synthesized Ag/AgCl nanoparticles exhibited potent antibacterial activity against both Gram-positive and Gram-negative bacteria. Notably, the presence of AgCl further enhanced their efficacy, expanding their potential for advanced antibacterial applications.