RESEARCH PAPER Qualitative assessment of silver and gold nanoparticle synthesis in various plants: a photobiological approach Pala Rajasekharreddy • Pathipati Usha Rani • Bojja Sreedhar Received: 16 December 2009 / Accepted: 1 March 2010 / Published online: 18 March 2010 Ó Springer Science+Business Media B.V. 2010 Abstract The development of rapid and ecofriendly processes for the synthesis of silver (Ag) and gold (Au) nanoparticles is of great importance in the field of nanotechnology. In this study, the extracellular production of Ag and Au nanoparticles was carried out from the leaves of the plants, Tridax procumbens L. (Coat buttons), Jatropa curcas L. (Barbados nut), Calotropis gigantea L. (Calotropis), Solanum melon- gena L. (Eggplant), Datura metel L. (Datura), Carica papaya L. (Papaya) and Citrus aurantium L. (Bitter orange) by the sunlight exposure method. Qualitative comparisons of the synthesized nanoparticles between the plants were measured. Among these T. procumbens, J. curcas and C. gigantea plants synthesized \ 20 nm sized and spherical-shaped Ag particles, whereas C. papaya, D. metel and S. melongena produced \ 20 nm sized monodispersed Au particles. The amount of nanoparticles synthe- sized and its qualitative characterization was done by UV–vis spectroscopy and transmission electron microscopy (TEM), respectively. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used for structural confirmation. Further anal- ysis carried out by fourier transform infrared spec- troscopy (FTIR), provided evidence for the presence of amino groups, which increased the stability of the synthesized nanoparticles. Keywords Silver nanoparticles Á Gold nanoparticles Á Biogenic synthesis of nanoparticles Á Sunlight Á Nanobiotechnology Introduction Nanomaterials synthesis and their characterization is an emerging field of nanotechnology from the past two decades, due to their huge applications in the fields of physics, chemistry, biology and medicine. With the development of several chemical-synthetic techniques, the concern for environmental contami- nations is also heightened as the chemical synthesis protocols need some toxic chemicals for synthesis (Song and Kim 2008). Most of the physical methods deal with enormous consumption of energy to maintain the high pressure and temperature employed in the synthesis procedures. With the increasing interest in minimization of waste and implementation of sustainable processes through the adoption of all the fundamental principles of green chemistry (Anastas and Warner 1998), the development of P. Rajasekharreddy Á P. Usha Rani (&) Biology and Biotechnology Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, Andhra Pradesh, India e-mail: purani@iict.res.in; usharani65@yahoo.com B. Sreedhar Inorganic and Physical Chemistry Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, Andhra Pradesh, India 123 J Nanopart Res (2010) 12:1711–1721 DOI 10.1007/s11051-010-9894-5