Drug Invention Today ISSN: 0975-7619 Research Article www.ditonline.info Corresponding Author: Dr. G. Annadurai, Associate Professor, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli – 627 412, Tamil Nadu, India; e-mail:< gannadurai@hotmail.com > Received 25-08-2012; Accepted 28-10-2012 October, 2012 Drug Invention Today, 2012, 4(10),511-513 Synthesis and Characterization of Antimicrobial Silver Nanoparticles Using Marine Brown Seaweed Padina tetrastromatica S. Rajeshkumar 1, 2 , C. Kannan 2 , G. Annadurai  1 1 Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi – 627 412, Tirunelveli, Tamil Nadu, India 2 Department of Chemistry, Manonmaniam Sundaranar University, Abishekapatti – 627 012, Tirunelveli, Tamil Nadu, India INTRODUCTION Padina tetrastromatica is the family of Dictyotaceae one of most pertinent marine brown sea weed and it will contains the major component of fucopyranosyl residues containing sulfated fucans called as fucoidans, Alginc acid and glucans were isolated from the seaweed and minor amount of glucronic acid and uronic acid are also found and they will play a important role in the field of Antiviral activities (1) . The application of nanosized materials and structures, usually ranging from 1 to 100 nanometers (nm), is a rising area of nanoscience and nanotechnology. The silver nanoparticles were prepared by various types of biological methods are bacteriological mediated like Bacillus licheniformis (2) , fungal mediated Aspergillus fumigates (3) , plant mediated nanoparticles are also growing vigorously now a day’s Persimmon (Diopyros kaki) (4) , Parthenium hysterophorus (5) , algae mediated nanoparticles synthesis are emerging in nanomaterials meadow Sargassum wightii Greville (6) , were synthesized the silver nanoparticles and they involves in the numerous biomedical applications. The silver nanoparticles are having key role in various applications are food processing applications (7) , electrochemical biosensor (8) , and also it used for various biomedical applications most one is antimicrobial activities especially antibacterial activities. The silver nanoparticles are having incredibly superior effect against in new resistant strains of bacteria which were causing health effect to human being and when compare to gram-positive organisms gram- negative bacteria vigorously affected by Silver nanomaterials (9) . Thereby, the present investigation was aimed at to find out the efficiency of marine brown algae Padina tetrastromatica extract in reduction of the toxic compound silver nitrate (AgNO3) into silver nanoparticles. The synthesized particles were characterized by UV-spectroscopic, diffraction assay, electron microscopic study and Fourier transmittance infrared spectroscopy. The antibacterial ability of the silver nanoparticles was tested against disease causing bacterial isolates. MATERIALS AND METHODS Preparation of Algal extract The brown algae Padina tetrastromatica was collected from Tuticorin coastal area in south Tamilnadu, India. And the silver nitrate was purchased from Thomas baker India limited. The marine brown seaweed containing waste materials in its surface area was thoroughly washed by using fresh tap water for several times and washed three times using distilled water may remove metallic compounds. After washing of the seaweed it involved in the process of drying especially involves shade drying at room temperature for ten days. The dried Algal materials were collected and it will crushed by using mortar and pestle to get the powder form. One gram of crushed algal powder was taken and added with 100ml of distilled water containing 250 ml conical flask. The conical flask was placed in heating mantle and heated for five minutes at 60 o to 80 o C. and boiled extract collected and kept in a sample bottle and it known as pure algal extract. Green synthesis and characterization of silver nanoparticles In the pure algal extract solution 1mM of silver nitrate (AgNo3) solution was added and the reaction of the colour change was observed. Colour changes of reacted solution was observed visually and from the colour changed solution absorbance was scrutinized from 340 to 580 nm at different time intervals using Double beam UV-Vis spectrophotometer (Perkin Elmer, Singapore) The synthesized nanoparticles involved for the morphological characterization by using the Transmission Electron Microscope. X-ray diffraction assay (Bruker, Jermany, model D8 Advance) was performed for the Using green technology for the synthesis of silver nanoparticles developed dynamically now a day. In this report we focused on the green synthesis of silver nanoparticles by using marine brown seaweed Padina tetrastromatica. The synthesized nanoparticles were scrutinized by UV-visible spectrophotometer shows the crest at 460 nm. X-ray crystallography confirmed the silver nanoparticles crystalline personality. The structure and size distribution of the silver nanoparticles were examined by Transmission Electron Microscope (TEM) in that average size is 14 nm clearly shown and most of the nanoparticles were in spherical in shape. Finally the compounds responsible for the silver nanoparticles biosynthesis were studied using Fourier Transmittance-Infrared Spectroscopy (FT-IR). The AgNPs exhibited antimicrobial activity against Bacillus sps, Klebsiella planticola, Bacillus subtilis and Pseudomonas sps. Thus, the brown algae could be used for eco friendly and efficient synthesis of antimicrobial silver nanoparticles. Key words: Biosynthesis, silver nanoparticles, Padina tetrastromatica, Antibacterial. 511