Open Journal of Biophysics, 2016, 6, 1-9 Published Online January 2016 in SciRes. http://www.scirp.org/journal/ojbiphy http://dx.doi.org/10.4236/ojbiphy.2016.61001 How to cite this paper: Ali, I.M., Ibrahim, I.M., Ahmed, E.F. and Abbas, Q.A. (2016) Structural and Characteristics of Man- ganese Doped Zinc Sulfide Nanoparticles and Its Antibacterial Effect against Gram-Positive and Gram-Negative Bacteria. Open Journal of Biophysics, 6, 1-9. http://dx.doi.org/10.4236/ojbiphy.2016.61001 Structural and Characteristics of Manganese Doped Zinc Sulfide Nanoparticles and Its Antibacterial Effect against Gram-Positive and Gram-Negative Bacteria Iftikhar M. Ali 1 , Isam M. Ibrahim 1 , Entissar F. Ahmed 2 , Qayes A. Abbas 3 1 Department of Physics, College of Science, University of Baghdad, Baghdad, Iraq 2 Department of Biology, College of Science, University of Baghdad, Baghdad, Iraq 3 Department of Physics, College of Education for Pure Science, University of Anbar, Ramadi, Iraq Received 9 October 2015; accepted 15 January 2016; published 18 January 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 Manganese doped zinc sulfide nanoparticles of the cubic zinc blende structure with the aver- age crystallite size of about 3.56 nm were synthesized using a coprecipitation method using Thio- glycolic Acid as an external capping agent for surface modification. The ZnS:Mn 2+ nanoparticles of diameter 3.56 nm were manufactured through using inexpensive precursors in an efficient and eco-friendly way. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Trans- form Infrared (FTIR) spectroscopy are used to examine the structure, morphology and chemical composition of the nanoparticles. The antimicrobial activity of (ZnS:Mn 2+ ) nanocrystals was inves- tigated by measuring the diameter of inhibition zone using well diffusion mechanism versus two various bacterial strains. The technique of microorganism inactivation was considered as sorts- dependent. Bacillus subtilis showed the largest antibacterial sensitivity (35 mm) to ZnS: Mn 2+ na- noparticles at a concentration (50 mM) whereas Escherichia coli offered maximum zone of inhibi- tion (20 mm) at the same concentration. In this study, the results indicated that ZnS:Mn 2+ nano- particles were found to have significant antibacterial activity against Gram-negative (E. coli) and Gram-positive (Bacillus subtilis) bacteria. Keywords Zinc Sulfide, Nanoparticles, Co-Precipitation Method, Antibacterial Activity