Naked-eye copper(II) sensing and antibacterial performance of silver nanoparticles synthesized using butterfly pea aqueous extract

This work demonstrates the capability of biosynthesized silver nanoparticles as a simple platform for copper(II) sensing together with the assessment of their antimicrobial activity. Butterfly pea aqueous extract was used to produce spherical AgNPs with sizes ranging from 10 to 30 nm showing the surface plasmon peak at 420 nm as a characteristic. The sensing capability of copper(II) was examined by observing an abrupt color change in colloidal AgNPs from a yellowish-brown to a light-violet color that was visible to the naked eye and occurred without any prior surface alteration. The synthesized AgNPs were found to be highly selective and sensitive in their application for identifying copper(II), with a detection limit of 6 mg L−1. The overall expression of copper(II) content in water and pharmaceutical samples was consistent with results obtained using the conventional AAS method. Furthermore, the antibacterial activity of the obtained AgNPs was also determined by the broth microdilution method. The minimum inhibitory concentration and minimum bactericidal concentration values against Methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, Acinetobacter baumannii clinical, and Acinetobacter baumannii were 0.16, 0.16, 0.32, 0.64 and 5.10, 5.10, 1.27, 1.27 μg mL−1, respectively.