Abstract

GREEN SYNTHESIS, CHARACTERIZATION AND APPLICATIONS OF SILVER NANOPARTICLES OF PADINA TETRASTROMATICA HAUCK.

A. Kingslin and P. Ravikumar*

ABSTRACT

Green synthesis of noble metal nanoparticles (NPs) is a developing area of current nanotechnology research. In this paper we report the green synthesis of silver nanoparticles (AgNPs) using the aqueous extract of brown seaweed Padina tetrastromatica as reducing agent and stabilizing agent. The reduction of silver ions occurred when silver nitrate solution was treated with aqueous extract of seaweed at40c. The AgNPs obtained were characterized by UV-Visible Spectroscopy, FESEM, EDAX, XRD and FTIR techniques. The formation of AgNPs is confirmed by the appearance signatory dark brown colour of the solution and a characteristic peak at 422 nm in the UV-Vis spectrum. The AgNP lattice is unaffected by other molecules in the algal extract as revealed in the XRD pattern. FESEM images revealed that the
synthesized NPs are spherical with size in the range of 85.85 - 89.75 nm. FTIR spectrum indicates the presence of different functional groups in capping the nanoparticles. The seedling growth was positively affected by certain concentration of AgNPs. The time taken for the mortality of the earthworm, Lampito mauritii in AgNO3 was 3minutes. The 1, 1-diphenyl-2-picrylydrazyl (DPPH) radical scavenging activities were highest in the concentration 500 ml (60.47%). Seaweeds are cost-effective, renewable marine resources. Their abundance and case of availability also make them good green reagents for the green synthesis of novel AgNPs. Exposure to nano-materials can encourage earlier seed germination and improve plant production as our results indicated in Vigna unguiculata, V. radiata and Cicer arietinum. The outcome of this basic research piece of work is useful to determine the biocompatibility of AgNPs of P.tetrastromatica.

Keywords: Green synthesis, Silver nanoparticles, Padina tetrastromatica, Characterization, Seed germination, Embryonic axis length, Lampito mauritii, Antioxidant activity.