%0 Journal Article
%T Biosynthesis and Characterization of Gold and Silver Nanoparticles Using Milk Thistle (Silybum marianum) Seed Extract
%A R. Gopalakrishnan
%A K. Raghu
%J Journal of Nanoscience
%D 2014
%R 10.1155/2014/905404
%X Biogenic synthesis of gold and silver nanoparticles from aqueous solutions using milk thistle (Silybum marianum) seed extract as reducing and stabilizing agent has been reported. Formation and stabilization of nanoparticles were monitored using surface plasmon resonance (SPR) bands of UV-Vis spectroscopy. Morphology of gold and silver nanoparticles was investigated using X-ray diffraction, high-resolution transmission electron microscopy with selected area electron diffraction analysis, and dynamic light scattering. Fourier transform-infrared spectroscopy was employed to identify the possible biomolecules responsible for the reduction and stabilization of nanoparticles. 1. Introduction Metallic nanoparticles have been considered as an important area of research due to their unique and tunable physicochemical properties and biological activities as compared to their bulk counterparts. In recent years, a numerous techniques such as physical vapour deposition, chemical vapour deposition, sol-gel synthesis, microwave assisted synthesis, ultrasonication, electrochemical synthesis, precipitation method, and biosynthesis have been reported for the synthesis of metallic nanoparticles [1¨C11]. Biosynthesis of metallic nanoparticles by using biological organisms and plant extract is an ecofriendly alternative to those involving toxic and hazardous chemicals [12¨C14]. Owing to their nontoxicity, the biosynthesized nanoparticles are widely used in medicinal applications [15, 16]. Noble metals like gold and silver have been familiar since ancient times owing to their ornamental and medicinal applications. These metallic nanostructures are reported to have their potential applications in anticancer drug delivery [17], catalysis, sensors [18], wound dressing [19], medical imaging [20], and antibacterial activity [21]. The application of noble metal nanoparticles based chemistry for drinking water purification has been reported for different types of contaminants recently [22]. In continuation of several reports for the biosynthesis of gold and silver nanoparticles [23¨C27], recently synthesis of silver nanoparticles using Silybum marianum seed extract and their characterization have been reported [28]. Here, we present a green and rapid synthesis of stable gold and silver nanoparticles using milk thistle (Silybum marianum) seed extract as reducing and stabilizing agent. Milk thistle (SM) is a plant of the Asteraceae family bearing purple flowers and pale green leaves with some mallow thorn. Extract from the seeds of SM contains 65¨C80% silymarin a (Flavonolignan complex),
%U http://www.hindawi.com/journals/jns/2014/905404/