Search

The study demonstrates ecofriendly and reproducible synthesis of Silver nanoparticles (SNPs) employing Ficus benghalensis (F.B.) leaf extract). In this paper, we report stable and spherical SNPs of variable size ranging from 10-50 nm. The formation of SNP was monitored using ultraviolet-visible spectroscopy (UV-Vis) technique for surface Plasmon resonance and it is found at 435 nm and absorbance peak at 280 and 240 nm are also found and indicates the protein and hydroxyl anthraquinones capping. The kinetics of effect of time, pH, ionic strength, Concentration of leaf extract and temperature on the formation of SNP was studied using UV-Vis spectroscopy. Fluorescence spectroscopy and Fourier-transform infrared spectroscopy (FTIR) studies indicate the involvement of protein as a capping agent and Quinones as reducing agents. The morphology of the SNPs was determined AFM (Atomic Force Microscopy) and FESEM (Field emission Scanning electron microscopy) along with EDAX. Xray diffraction (XRD) study was carried and found to be face centred cube (fcc).Thermal Gravimetric analysis (TGA) was performed to understand the thermal behaviour of biosynthesized silver nanoparticles. The results indicated that the proteins, which have amine groups, have played a significant role in stabilizing SNPs in the solutions.

In this paper, we stress upon rapid synthesis of irregular shape gold nanoparticles from a biological base. Treatment of macerated extracellular aqueous dried clove buds (Syzygium aromaticum) solution with the aqueous gold salt solution yielded irregular shaped stable gold nanoparticles in the range of 5-100 nm. The synthesis and morphology of these gold nanoparticles are understood by UV (UV-vis spectroscopy), FESEM (field emission scanning electron microscopy), TEM (transmission electron microscopy) and AFM (atomic force microscopy) techniques. The formation of these bio-adsorbed gold nanoparticles is rapid as the reaction process completes within few minutes. The XRD (X-ray diffraction studies) and EDAX (energy dispersive X-ray analysis) show that the particles are crystalline in nature. This clean-green method of synthesis is performed under ambient conditions. Probable biochemical pathway of the synthesis is studied using FTIR (Fourier transformed infrared spectroscopy). It is observed that the freely water soluble flavonoids of clove buds are responsible for bioreduction. The possible applications viz., catalysis, sensor, diagnostics, biomedical imaging and photo thermal therapy of these functionalized noble metal nanoparticles are envisaged.

Polyaniline (Pani) and Polyaniline-silver nanocomposites (Pani-Ag) were prepared by employing interfacial polymerization using ammonium persulphate as an oxidizing agent. During the polymerization, the Ag+ is reduced to Ag0, and the formations of regular nanocomposite materials were studied by Fourier transform infrared spectroscopy and UV–visible spectroscopy techniques. Scanning electron microscopy and transmission electron microscopy images were conducted to characterize the morphology. Thermogravimetric and differential thermal analysis were carried out to study the thermal stability of the resulting composites. Formation of conducting emeraldine salt form was concluded by electrical conductivity. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Crystallized and spherical-shaped Au and Au–Ag alloy nanoparticles have been synthesized and stabilized using a fungus, F . semitectum in an aqueous system. Aqueous solutions of chloroaurate ions for Au and chloroaurate and Ag+ ions (1 : 1 ratio) for Au–Ag alloy were treated with an extracellular filtrate of F . semitectum biomass for the formation of Au nanoparticles (AuNP) and Au–Ag alloy nanoparticles (Au–AgNP). Analysis of the feasibility of the biosynthesized nanoparticles and core–shell alloy nanoparticles from fungal strains is particularly significant. The resultant colloidal suspensions are highly stable for many weeks. The obtained Au and Au–Ag alloy nanoparticles were characterized by the surface plasmon resonance (SPR) peaks using a UV-vis spectrophotometer, and the structure, morphology and size were determined by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and transmission electron microscopy (TEM). Possible optoelectronics and medical applications of these nanoparticles are envisaged.

This is an extended work on the biosynthesis of noble metal nanoparticles using dried clove buds. Here microwave assistance is taken not only for accelerating the reaction rate but also for denaturing the proteins and other enzymes, which will prevent obtaining desired functionalized nanoparticles. FTIR studies infer that nanoparticles thus obtained are found adsorbed with water soluble organic moieties, mostly flavonoids. The bathochromic shift from 320 nm in ultra-violet range indicates the involvement of water soluble bio-moieties of the clove in the formation of AgNP . X-ray diffraction (XRD) spectrum confirmed that the AgNP are crystalline in nature. The surface morphology is studied using FESEM, TEM and AFM techniques infer that the AgNP are well dispersed, roughly spherical in shape and are in the range of 30–60 nm. The AgNP with the organic moiety will have synergic antimicrobial action.