Antibacterial and Catalytic Efficacy of Biosynthesized Silver Nanoparticles Using Marine Seaweed Padina Tetrasromatica

Abstract

Utilization of renewable marine resources for the biosynthesis of metal nanoparticles is an innovative area in the current nanotechnology research. The present article reports a simple environmentally benign method for the synthesis of silver nanoparticles using aqueous extract of marine brown seaweed Padina Tetrastromatica, which act as both the reducing and stabilising agent. The formation, morphology and crystalline nature of the synthesised silver nanoparticles were determined using UV-Visible Spectroscopy, Transmission electron microscopy, Selected area electron diffraction and X-ray diffraction techniques. The surface plasmon resonance peak at 424 nm in the UV-Visible spectrum confirmed the formation of silver nanoparticles. The biosynthesised silver nanoparticles were almost spherical with an average size of 15 nm. Crystalline nature of silver nanoparticles is evident from the characteristic peaks in the X-ray diffraction pattern, bright circular spots in the selected area electron diffraction pattern and clear lattice fringes in the High resolution Transmission electron microscopy images. Fourier transform infrared spectroscopic analysis revealed the presence of functional bio active metabolites in seaweed extract which is responsible for the formation and efficient stabilization of the nanoparticles. The biosynthesised silver nanoparticles show excellent antimicrobial activity against Escherichia coli and Aeromonas hydrophila. They also show very good catalytic activity for the reduction of methylene blue in the presence of NaBH4 in aqueous medium. Thus the green synthesised nanoparticles are expected to be a promising candidate for the application in diverse fields.

Keywords

• biosynthesis
• silver nanoparticles
• padina tetrastromatica
• catalysis
• methylene blue
• antibacterial activity