Synthesis of <i>Padina tetrastromatica</i> Seaweed Mediated Silver Nanoparticles and its Toxicological Evaluation against Brine Shrimp <i>Artemia</i>

Abstract

The present study evaluates the toxicity of AgNPs synthesised from Padina tetrastromatica (P-AgNPs) through Brine Shrimp Lethality Assay. The aqueous Padina seaweed extract was treated with AgNO3 to synthesise P-AgNPs, and these NPs were then characterised by multiple analytical techniques. The UV-Vis spectra displayed characteristic SPR peaks of AgNPs at about 409.5 nm. The TEM and particle size distribution results verified the formation of polydisperse spherical P-AgNPs with a dominant size of around 48 nm. Zeta potential analysis indicates the moderate stability of P-AgNPs. The FTIR spectrum of P-AgNPs reveals the presence of organic functional groups, suggesting the involvements of seaweed organic matters in capping and stabilising AgNPs. Though the 24-h mortality test showed a dose-dependent increase in Artemia death, the results imply a non-toxic property in P-AgNPs (LC50 value: 4300 mg/L; >1000 mg/L). These findings conclusively suggest the acute exposure to P-AgNPs has no substantial risk to marine organisms.