Green and Sustainable Chemistry, 2016, 6, 34-56 Published Online February 2016 in SciRes. http://www.scirp.org/journal/gsc http://dx.doi.org/10.4236/gsc.2016.61004 How to cite this paper: Srikar, S.K., Giri, D.D., Pal, D.B., Mishra, P.K. and Upadhyay, S.N. (2016) Green Synthesis of Silver Nanoparticles: A Review. Green and Sustainable Chemistry, 6, 34-56. http://dx.doi.org/10.4236/gsc.2016.61004 Green Synthesis of Silver Nanoparticles: A Review Sista Kameswara Srikar 1,2* , Deen Dayal Giri 1,3 , Dan Bahadur Pal 1 , Pradeep Kumar Mishra 1 , Siddh Nath Upadhyay 1* 1 Department of Chemical Engineering & Technology, Indian Institute of Technology (BHU) Varanasi, Varanasi, Uttar Pradesh, India 2 Tata Steel, Jamshedpur, Jharkhand, India 3 Department of Botany, IFTM University, Moradabad, Uttar Pradesh, India Received 30 October 2015; accepted 26 February 2016; published 29 February 2016 Copyright © 2016 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract The bio-molecules from various plant components and microbial species have been used as po- tential agents for the synthesis of silver nanoparticles (AgNPs). In spite of a wide range of bio-mol- ecules assisting in the process, synthesizing stable and widely applicable AgNPs by many re- searchers still poses a considerable challenge to the researchers. The biological agents for synthe- sizing AgNPs cover compounds produced naturally in microbes and plants. More than 100 differ- ent biological sources for synthesizing AgNPs are reported in the past decade by various authors. Reaction parameters under which the AgNPs were being synthesized hold prominent impact on their size, shape and application. Available published information on AgNPs synthesis, effects of various parameters, characterization techniques, properties and their application are summa- rised and critically discussed in this review. Keywords AgNPs, Green Synthesis, Silver Nano, Plant Extract, Microbe 1. Introduction Materials in the nano dimensions (1 - 100 nm) have remarkable difference in the properties compared to the same material in the bulk. These differences lie in the physical and structural properties of atoms, molecules and * Corresponding author.