International Science Community Association Research Journal of Chemical Sciences 2231-606X 8 2 2018 02 18 Bioconstruction of copper nanoparticles using stem bark extract of Picralima nitida and their antibacterial potency 10 15 EN Shalini Singh 1 Department of Environment Assessment and Remediation, CSIR-Central Institute of Mining and Fuel Research, Dhanbad, Jharkhand, India Anuradha Singh 2 Division of Biotechnology, CytoGene Research and Development, Lucknow, UP, India O.U. Igwe 1 Department of Chemistry, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267 Umuahia, Abia State, Nigeria C.M. Ejiako 2 Department of Chemistry, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267 Umuahia, Abia State, Nigeria > Research Paper 2017 11 12 2018 02 18 Copper nanoparticles are involved in several applications due to the fact that they possess certain desirable properties. In this research report, copper nanoparticles have been synthesized by a green approach using the stem bark extract of Picralima nitida. The nanoparticles were characterised using UV-visible spectroscopy, FT-IR spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) method. The change in colour observed during copper nanoparticles synthesis from orange to golden yellow within 10 minutes confirms the formation of copper nanoparticles. The surface Plasmon peak indicating the formation of copper nanoparticles appeared at 213 nm. FT-IR spectroscopy was used to investigate interactions and changes in chemical compositions of the mixtures during biosynthesis. The FT-IR spectra of the copper nanoparticles and that of the stem bark extract were similar with minor differences. The similarity of the two spectra indicates that the components of P. nitida stem bark extract got attached to the copper nanoparticles retaining their essential features. The morphology of the copper nanoparticles reveals that the particles consist of spherical, cubic and irregular shaped structures with smooth surfaces. XRD analysis reveals the crystalline nature of the bio-synthesized copper nanoparticles with average size to be in the range of 35-61 nm. The copper nanoparticles showed potent inhibition against Pseudomonas aeruginosa which is a Gram-negative bacterium but with lesser effect on Staphylococcus aureus which is a Gram-positive bacterium. The copper nanoparticles synthesized here could be employed in the treatment of diseases caused by P. aeruginosa and S. aureus. Copyright@ International Science Community Association