Root Extracts (<i>Gymnadenia orchidis</i> Lindl) Facilitated Rapid Synthesis of Fluorescent Silver Nanoparticles (Ag-NPs) for Various Biological Applications

Abstract

One pot rapid and green bio-synthesis of stable fluorescent silver nanoparticles (Ag-NPs) from silver nitrate solution using root extract of Gymnadenia orchidis Lindlat at ambient temperature is demonstrated productively. Surface Plasmon resonance of the synthesized Ag-NPs was shown to occur at 439 nm and two sharp fluorescence peaks at 610 and 780 nm were observed. FTIR study publicized the presence of chemically functional groups in the root extract surrounding the Ag-NPs, acting as stabilizers. XRD and FESEM analysis revealed that Ag-NPs were face centred cubic structure being spherical in shape with an average particle size of 28 ± 2 nm (n = 100). The stability of Ag-NPs in neutral pH environment was confirmed by Zeta Potential (ζ) behaviour. The Ag-NPs showed superior antioxidant activity. The notable photo-catalytic activity of biosynthesized Ag-NPs attributed to the existence of some proteins, responsible for degradation of methylene blue dye. Furthermore, Ag-NPs were found to exhibit a significant antibacterial effect against gram positive Staphylococcus aureus (S. aureus) bacteria.