Colloids and Surfaces B: Biointerfaces 95 (2012) 284–288 Contents lists available at SciVerse ScienceDirect Colloids and Surfaces B: Biointerfaces j our na l ho me p age: www.elsevier.com/locate/colsurfb Short communication Novel route for rapid biosynthesis of copper nanoparticles using aqueous extract of Calotropis procera L. latex and their cytotoxicity on tumor cells Shrikant Harne a , Ashwinikumar Sharma b , Mayur Dhaygude b , Shreeram Joglekar c , Kisan Kodam c , Manish Hudlikar d,∗ a Department of Microbiology, University of Pune, Pune 411007, Maharashtra, India b Polymer Science and Engineering Division, National Chemical Laboratory, Pashan, Pune 411008, Maharashtra, India c Division of Biochemistry, Department of Chemistry, University of Pune, Pune 411007, Maharashtra, India d Department of Chemistry, University of Georgia, Athens GA-30605, USA a r t i c l e i n f o Article history: Received 19 January 2012 Received in revised form 1 March 2012 Accepted 12 March 2012 Available online 20 March 2012 Keywords: Biocompatible Latex Copper nanoparticles X-ray diffraction technique (XRD) FTIR Tumor cells a b s t r a c t This paper accounts for novel, low-cost, eco-friendly route for rapid biosynthesis of copper nanoparticles. Cysteine proteases present in the latex of Calotropis procera L. were used to fabricate copper nanopar- ticles from copper acetate. Copper nanoparticles were initially characterized by transmission electron microscopy (TEM) and X-ray diffraction technique (XRD). Transmission electron microscopy (TEM) was used to estimate the size and shape of nanoparticles. The average size of copper nanoparticles was found to be 15 ± 1.7 nm. Energy dispersive analysis of X-rays (EDAX) showed distinct peaks of copper. Fourier transform infrared spectroscopy (FTIR) was performed to confirm capping behavior of the latex proteins that contributed to long term stability of copper nanoparticles (6 months) in aqueous medium. Cop- per nanoparticles synthesized by above method were monodisperse type. Cytotoxicity studies of latex stabilized copper nanoparticles were carried out on HeLa, A549 and BHK21 cell lines by MTT dye con- version assay. HeLa, A549 and BHK21 cells showed excellent viability even at 120 M concentration of copper nanoparticles. This shows that copper nanoparticles synthesized by above method hold excellent biocompatibility. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Copper nanoparticles are making significant progress in the area of nanotechnology and nanomedicine for last ten years because of their excellent catalytic, optical, electrical and anti- fungal/antibacterial applications [1,2]. Copper nanoparticles have been prepared using following methods such as thermal reduction [3], vacuum vapor deposition [4], microwave irradiation methods [5], chemical reduction [6], and laser ablation [7]. Polyol method reported by Park et al. [8] synthesized highly monodispersive cop- per nanoparticles in air atmosphere. Biosynthesis of copper nanoparticle was reported by Valodkar et al. [9] using medicinally important plant Euphorbia nivulia L. and shown their biological effects on tumor cells. Yoon et al. [10] and Cioffi et al. [11] have reported the antifungal and bacterio- static properties of copper nanoparticles recently. This shows that, ∗ Corresponding author. Tel.: +1 478 394 2737. E-mail addresses: manishhudlikar@gmail.com, manish21@uga.edu (M. Hudlikar). copper nanoparticles could serve as a potential candidate in follow- ing applications such as nanomedicine, water treatment and food processing. Calotropis procera L. has various uses in Indian traditional medic- inal systems [12,13]. Milky white latex of this plant exhibits diverse curative properties [14]. Particularly latex of this plant is rich in protein including anti-oxidant enzymes (AOEs), cysteine protease with free thiol ( SH) group and tryptophan [15–17]. Present work deals with synthesis of copper nanoparticles at room temperature using 0.5% aqueous extract prepared from C. procera L. latex with average diameter of 15 ± 1.7 nm. Biosynthe- sized copper nanoparticles showed excellent long term stability in aqueous medium. This show that anti-oxidant enzymes (AOEs), cysteine protease with free thiol ( SH) group and tryptophan present in the latex of C. procera L. played important role in reduc- ing and stabilizing copper nanoparticles. Cytotoxicity studies of latex stabilized copper nanoparticles were carried out on HeLa, A549 and BHK21 cell lines by MTT dye conversion assay. HeLa, A549 and BHK21 cells showed excellent viability even at 120 M concentration of copper nanoparticles. This shows that copper nanoparticles synthesized by above method holds excellent bio- compatibility. 0927-7765/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2012.03.005