Digest Journal of Nanomaterials and Biostructures Vol. 9, No. 3, July - September 2014, p. 1007 - 1019 BIO-SYNTHESIS OF NiO AND Ni NANOPARTICLES AND THEIR CHARACTERIZATION A. AYESHA MARIAM a* , M. KASHIF b , S. AROKIYARAJ c , M. BOUOUDINA d,e , M. G. V. SANKARACHARYULU f , M. JAYACHANDRAN g , U. HASHIM b a Department of Physics, Khadir Mohideen College, Adirampattinam, 614 701, India b Nano Biochip Research Group, Institute of Nano Electronic Engineering (INEE), Universiti Malaysia Perlis (UniMAP), 01000 Kangar, Perlis, Malaysia c Animal Nutrition and Physiology, National Institute of Animal Science, Republic of Korea d Nanotechnology Centre, University of Bahrain, PO Box 32038, Kingdom of Bahrain e Department of Physics, College of Science, University of Bahrain, PO Box 32038, Kingdom of Bahrain f Arignar Anna Government Arts & Science College, Karaikal , Karaikal District, 609605, India g Electro Chemical Material Science Division, Central Electro Chemical Research Institute (CSIR), Karaikudi, 630 006, India NiO and Ni nanoparticles (NPs) were successfully synthesized by boiling method using leaves of Azadirachta indica and Psidium guajava. The size and morphology of the particles was found to be in the range of 17-77 nm by Transmission electron microscopy and Scanning electron microscopy. X-ray diffraction analysis and Atomic mass spectrograph confirms the formation of pure Ni and NiO cubic phases with an average crystallite size of 44 and 22 nm. The absorbance of NiO nanoparticles were observed by absorbance spectra and magnetic flux density values are 60 emu/g of this sample but for metallic nanoparticle of Ni there was no absorbance was observed. Further the synthesised Ni and NiO nanoparticles showed cytotoxic effect against HT29 cell line. Further study is required to identify the anticancer mechanism of the synthesised Ni and NiO nanoparticles that may use for cancer therapy. (Received June 17, 2014; Accepted August 11, 2014) Keywords: Ni and NiO; nanoparticles; SEM and TEM; magnetic properties, Cytotoxic. 1. Introduction More attention has been devoted on nanoscale magnetic transition metal-based materials, including Ni, Co and Fe due to their superior magnetic properties and potential applications. Integration of green chemistry principles to nanotechnology is one of the key issues in nanoscience research. Nanobiotechnology combines biological principles with physical and chemical procedures to generate nano-sized particles with specific functions. Recently many attempts have been made to develop processes and techniques that would yield nanoparticles (NPs) with definite size and shape (Matijevic, 1993). Jennifer A. et al. (2007) reported that, the nature of engineered nanomaterials and their proposed uses provides compelling reasons for the implementation of green chemistry in the development of new materials and applications. The technology is in their early development stage and expected to be widely applied and distributed. These materials are expected to (i) exhibit new size-based properties (both beneficial and detrimental) that are * Corresponding author : aismma786@gmail.com