Indian Journal of Geo Marine Sciences Vol. 46 (01), January 2017, pp. 125-130 Green synthesis of silver nanoparticles using marine sponge Axinella sinoxia Mahta Rezazadeh Hamed, Mohammad Hadi Givianrad * & Ali Mashinchian Moradi Department of Marine Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran * [Email: givianradh@yahoo.com ] Received 12 August 2015; revised 03 November 2015 Silver nanoparticles synthesis using dry and fresh marine sponge Axinella sinoxia. Experimental parameters such as time duration, pH, and temperature are studied. Optimizations for silver nanoparticles were carried out. The optimum syntheses of silver nanoparticles were achieved within 4 hours at pH 8.5, 70 ˚C and 1mM AgNO 3 . Characterizations of silver nanoparticles were applied based on UV-Vis spectrophotometry around 420 nm .The sizes of synthesized nanoparticles (23-38nm) were confirmed by scanning electron microscopy (SEM). X-ray diffraction (XRD) crystallography expounded the silver nanoparticles crystalline nature. Fourier transform infrared spectroscopy (FT-IR) shows that the functional groups are hydroxyl, carbonyl, amide, amine, alkyl halide, and phenolic compounds of extract of Axinella sinoxia are entangled in the reduction of aqueous silver nanoparticles. This method of Ag-NPs synthesis does not use any toxic reagents and thus has potential for use in biomedical, pharmaceutical and agricultural application. [Keywords: Green synthesis, Silver nanoparticles, Sponge, Axinella sinoxia, SEM, XRD] Introduction Marine bio-nanotechnology is an exciting and upcoming area of investigation 1 . The biologically various marine environment has a great promise for nanoscience and nanotechnology. Nanobiotechnology is a course that depends on both science and nanotechnology 2. Nanoparticles can be synthesized by chemical, physical and biological procedures 3 . Nanoparticles generally have unique properties and changed physical and biological properties compared. Synthesis of noble metal NPs for usage such as catalysis electronics, optics, environmental, and biotechnology is an area of constant intrest 4 . Preparation of nanoparticles by green technologies is advantageous over chemical agents due to their environmental achievement 5 . Chemical and physical procedures are very expensive and involve the use of toxic, harmful chemical, which may pose potential environmental and biological dangers 6-7 . Physically and chemically mediated syntheses require high pressure, energy, temperature, high cost and toxicity 8 . Silver an old element is being wildly used as antibacterial agent since 19 th century although it has been discovered since ancient Babylonians and Greeks periods 9 . Silver is well known to rush a wide range of bacteria's by modified the cell membrane structure and its functions. Silver also kills bacteria less than 1-10 µm and therefore it is being used as an antiseptic agent in water purification systems. Thus silver has been extensively used for development of many biological and medicinal products 10 . Silver nanoparticles have specification physico-chemical properties such as high electrical and thermal conductivity surface enhanced Raman scattering, chemical stability, catalystic activity and non- linear optical behavior 11 . Extract from bio organisms may act reducing agents in silver nanoparticles synthesis. The reduction of silver ions by combination of biomolecules found in these extracts extract includes enzymes/proteins, amino acids polysaccharides and vitamins are environmentally safeness, yet chemically complex 12 . Synthesis of silver nanoparticles using biological marine microorganisms such as bacteria, actinomycetes, yeast, fungi 13 and plants were reported 14 . Silver nanoparticles using marine animals such as sponges have been undiscovered which aroused our interest 15 . Synthesis of nanoparticles may be to do several compounds includes carbonyl groups terpenoids, phenolics,