* Corresponding author: E-mail: sixmuga@yahoo.com ISSN: 0976-3031 RESEARCH ARTICLE GREEN SYNTHESIS, CHARACTERIZATION OF SILVER, GOLD AND BIMETALLIC NANOPARTICLES USING BARK EXTRACT OF TERMINALIA ARJUNA AND THEIR LARVICIDAL ACTIVITY AGAINST MALARIA VECTOR, ANOPHELES STEPHENSI Kasi Gopinath 1 , Chandran Sundaravadivelan 2 , Ayyakannu Arumugam 1* 1 Department of Nanoscience and Technology, Alagappa University, Karaikudi 630 004, Tamil Nadu, India 2 Department of Zoology, Karpagam University, Coimbatore 641 021, Tamil Nadu, India ARTICLE INFO ABSTRACT Green synthesis is one of the rapid, reliable and best routes for synthesis of silver (Ag), gold (Au) and bimetallic (Ag/Au) nanoparticles (NPs). The present study revealed that synthesis of spherical Ag, Au and Ag/Au nanoparticles using aqueous bark filtrate of Terminalia arjuna which contains arjunetin, leucoanthocyanidins and hydrolysable tannins, which are found to be responsible for bioreduction of Ag + , Au + and Ag + /Au + ions to form as Ag 0 , Au 0 and Ag 0 /Au 0 biometals. The synthesized Ag, Au and Ag/Au NPs were characterized by UV-visible spectrophotometer, Fourier Transform Infra-red (FTIR), X-ray diffraction (XRD), Energy- dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM) analysis for detecting the absorption range, possible functional metabolites, particles nature and size and shape, respectively. UV–visible spectra of aqueous reaction medium containing Ag, Au and Ag/Au nanoparticles showed peak at 430, 530 and 480 nm respectively, due to surface plasmon resonance. FTIR spectra indicate the presence of amines and amides responsible for synthesis of nanoparticles. The crystalline nature with face centered cubic geometry and their preferential orientation along (111) plane of NPs were analyzed through XRD. The EDS analysis showed the completed composition of the synthesized biometals like Ag, Au and Ag/Au NPs. The sizes about 20-60 nm and spherical shaped particles were ascertained by surface analysis using SEM. The efficacy of the synthesized Ag, Au and Ag/Au NPs were tested against third and fourth instars larvae of malarial vector Anopheles stephensi. The results showed that Ag/Au NPs were more significant effect compare with Ag and Au NPs treatment alone. The phyto-mediated synthesized nanoparticles can be a rapid, simple, cost effective and environmentally safer bio- pesticide for controlling the malarial vector. INTRODUCTION Nanostructured materials have been attracting considerable attention because of their unique properties with wide application in many fields such as catalysis (Kim et al., 2003), optical devices (Kamat 2002), cell labeling (Wu et al ., 2003), cell tracking (Parak et al., 2002), in vivo imaging (Dubertret et al., 2002), therapeutics (Shrivastava et al., 2009), DNA detection (Taylor et al., 2000) and antimicrobial activity (Krishnaraj et al., 2012). Nowadays, various physical and chemical methods using chemical vapour deposition, sol–gel technique, aerosol technology, sono chemical method and photochemical reduction have been demonstrated for synthesis of nanoparticles. Even though, they are expensive and required high pressure, energy and temperature, therefore these methods are considered as toxic and potentially hazardous to environment. In contrast, extract obtained from plants and microbes containing active metabolites served as alternative green route for synthesis of nanoparticles with eco-friendly approach. Further, it is simple, conventional, rapid, accurate, single-step approach, cost-effective and eco-friendly. Extracts obtained from plants found to be presence of active metabolites like alkaloids, saponines, terpenoids, anthocyanines, cardenolides and flavonoids (Jhoo et al., 2005), polyphenolic compounds (Begum et al., 2009), theaflavins and thearubigins (Hertog et al., 1993), protein (Ahmad et al., 2003) and enzymes (Kumar et al., 2007) which are responsible for possible reduction of complex chemical, silver nitrate and gold chloride into single molecule like silver and gold as biometal with bioactivity. In this respect, aqueous leaves extract of Artocarpus heterophyllus (Jagtap and Bapa 2013), Sesbania grandiflora (Das et al., 2013), Punica granatum (Edison and Sethuraman 2013), Pithecellobium dulce (Raman et al ., 2012), Malva parviflora (Zayed et al., 2012) and Iresine herbstii (Dipankar and Murugan 2012) for silver nanoparticles, Macrotyloma uniflorum (Aromal et al., 2012), Terminalia chebula (Kumar et al., 2012), Trigonella foenum- graecum (Aswathy Aromal and Philip 2012) and Murraya koenigii (Philip et al ., 2011) for gold nanoparticles, and Swietenia mahogani (Mondal et al ., 2011), Piper pedicellatum (Tamuly et al., 2013) and Black Tea leaf extract (Begum et al., 2009) for silver and gold bimetallic nanoparticles have been reported for phyto-synthesis. Terminalia arjuna (Roxb.) Wight & Arn. is a large evergreen tree belongs to family Combretaceae, commonly found in south and central region of India. Morphologically, it has oblong, conical Available Online at http:/ / www.recentscientific.com International Journal of Recent Scientific Research International Journal of Recent Scientific Research Vol. 4, Issue, 6, pp.904 - 910, June, 2013 Article History: Received 19 th , April, 2013 Received in revised form 15 th , May, 2013 Accepted 29 th , May, 2013 Published online 30 th June, 2013 Key words: Terminalia arjuna, Bark filtrate, Nanoparticles, Green synthesis, Larvicidal activity, Anopheles stephensi, Bio-pesticide. © Copy Right, IJRSR, 2013, Academic Journals. All rights reserved.