In this study, green synthesis and physicochemical characterization of silver nanoparticles (AgNPs) using S.nervosum leaf extract. The characteristic surface plasmon resonance peak observed in the visible region at 435 nm is consistent with previous reports of silver nanoparticle formation. The synthesized AgNPs were also characterized by SEM, TEM, XRD, and FTIR, which reveal their nearly spherical shape, mainly in the 10–30 nm diameter. The antimicrobial activity of AgNPs was studied using the agar-well diffusion method on four clinically significant pathogenic microorganisms (P.aeruginosa ATCC 27853; E.coli ATCC 35218, S.aureus ATCC 12493; S.aureus Mastitis isolate). The results showed that the green synthesized AgNPs exhibited antimicrobial activity at most studied concentrations, including the antibacterial effect against S.aureus (Mastitis isolate) strain, which was found to be resistant to Tetracycline 100 µg/L. The antifungal activity of these nanoparticles was also studied on Colletotrichum gloeopsoriodes by colony formation assay. The green synthesis of silver nanoparticles (AgNPs) was successfully conducted for the first time utilizing the aqueous extract of S.nervosum. The results of this study indicate that silver nanoparticles have potential applications as antibacterial and antifungal agents.

Polydopamine (PDA) is an emerging biomimetic material that stimulates the distinctive physicochemical properties of the blue mussel byssus. In this study, we report a rapid and facile method for the decoration of gold nanoparticles (AuNPs) onto the mussel-inspired polydopamine nanospheres (PDA NSs) via cold atmospheric plasma treatment. After 10 min of plasma treatment, AuNPs with a size of 10.3 ± 2.0 nm were formed on the surface of PDA NSs. This reaction was performed without the need for any additional reducing agents, thereby eliminating the use of harsh chemicals during the process. The synthesized AuNP-decorated PDA nanohybrids (PDA-Au) exhibit effective catalytic activity for the decoloration of Rhodamine B, with a pseudo-first-order rate constant of 1.405 min⁻¹. The green synthesis approach in this work highlights the potential of plasma-assisted methods for decorating biomimetic materials with metallic nanoparticles for catalytic and environmental applications.