One step phytosynthesis of highly stabilized silver nanoparticles using Piper nigrum extract and their antibacterial activity N. Jayaprakash a,b , J. Judith Vijaya a,n , L. John Kennedy c , K. Priadharsini d , P. Palani d a Catalysis and Nanomaterials Research Laboratory, Department of Chemistry, Loyola College, Chennai 600 034, India b SRM Valliammai Engineering College, Department of Chemistry, Chennai 603 203, India c Materials Division, School of Advanced Sciences, VIT University, Chennai Campus, Chennai 600 048, India d Department of Center for Advanced Study in Botany, University of Madras, Guindy Campus, Chennai 600 025, India article info Article history: Received 19 May 2014 Accepted 5 September 2014 Available online 16 September 2014 Keywords: Silver nanoparticles Phytosynthesis Electron microscopy Antibacterial activity abstract One step phytosynthesis of highly stabilized silver nanoparticles (AgNPs) had been produced by using the extract of Piper nigrum (black pepper) as a reducing and a capping agent in aqueous medium, without the addition of any other chemicals. UV–visible (UV–vis) spectra showed the formation of AgNPs by observing the surface plasmon resonance (SPR) band at 444 nm. X-ray diffraction (XRD) analysis confirmed the formation of AgNPs with face centered cubic (fcc) structure. Fourier transform infra-red (FT-IR) spectra were used to identify the functional groups present in the biomolecules for reduction and capping of AgNPs. The electrochemical behaviour was carried out by cyclic voltammetry (CV). Oval-like morphology of the sample was confirmed by high-resolution scanning electron microscopy (HR-SEM) and high-resolution transmission electron microscopy (HR-TEM). Elemental composition was found out by the energy dispersive X-ray analysis (EDX). The antibacterial activities were carried out and revealed good results. This phytosynthetic approach is facile, inexpensive, reproducible, and eco-friendly. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Silver nanoparticles (AgNPs) play a significant role in the field of opto-electronics, catalysis, sensors, medical, and water treat- ment [1]. AgNPs have been projected as the future generation antimicrobial agents for its strong anti-microbial activity. Oxida- tion of AgNPs is thermodynamically unfavorable, due to the large positive reduction potential, and, thus, resulting in quite stable condition in aqueous and alcoholic suspensions without the aid of capping agents. Though, many physical and chemical synthetic methods are available, biological synthesis of nanoparticles pro- vides advancement over other methods. As a result of the draw- backs (using toxic chemicals and solvents) of chemical synthesis, a biological synthesis method is developed to obtain the biocompa- tible, inexpensive and eco-friendly, size-controlled nanoparticles. Recently, the use of environmentally benign materials like plant leaf extract, fruits, bacteria, and fungi for the synthesis of silver nanoparticles offered numerous benefits like easy to carry out, more economical than the traditional one, eco-friendliness and compatibility for pharmaceutical and biomedical applications [2]. These environmentally benign materials are capable to produce highly stable nanoparticles, which prevent the molecular aggrega- tion even after the prolonged storage. Piper nigrum belongs to Piperaceae family. It is used as a main ingredient in traditional medicines and flavors in food. In the present study, we have described the ability of the extract of P. nigrum to synthesize oval shaped, highly stabilized, and bactericidal AgNPs without any additional chemicals for reduction and capping. pH is maintained as it is. Therefore, it is totally a green synthesis, very simple, cost-effective, and, envir- onmentally benign. 2. Experimental Materials: Silver nitrate (AgNO 3 ) was purchased from Qualigens, and P. nigrum was purchased from the market in Kanchipuram, Tamil Nadu, India. They were used without any further purification for the synthesis of AgNPs along with de-ionized water. Characterization techniques: AgNPs are characterized by using UV–Visible spectra (Shimadzu 1800 spectrophotometer), XRD (XPERT-PRO diffractometer with Cu K α1 , λ ¼ 1.54056 Å), FT-IR (BRU- KER, Alpha T model), CV (CHI 600A electrochemical workstation), HR-SEM (FE I Quata FEG 200), and HR-TEM (TECHNAI, FEI G 2 model T-30, S-twin, 300 kV). Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/matlet Materials Letters http://dx.doi.org/10.1016/j.matlet.2014.09.027 0167-577X/& 2014 Elsevier B.V. All rights reserved. n Corresponding author. Tel.: þ91 44 28178200; fax: þ91 44 28175566. E-mail addresses: jjvijayaloyola@yahoo.co.in, jjvijaya78@gmail.com (J. Judith Vijaya). Materials Letters 137 (2014) 358–361