Ph.D Research Scholar, Birla Institute of Technology
GNPs are biosynthesized which can be used as carrier molecules for drug, DNA and bio-active molecule
The recent advances for a reliable, eco-friendly, non-toxic processes for the synthesis of nanomaterials has become a prone area of nanotechnology’s researcher now a days. Despite sculpturing the synthesis of nano particles to desired characters, the application of them in biomedical field is still limited due to the presence of toxic chemicals used in their synthesis. This has motivated the research in nano particles synthesis through biological route.One of the promising method that shows a huge potential is grounded on the biosynthesis of nanoparticles using biological sources like plants, micro-organisms such as bacteria, fungi, algae and others. In this study, a non-hazardous method biosynthesis approach for the synthesis of gold nano particles (GNPs) has been investigated using marine bacteria procured from Southern Ocean particularly in Indian sector. The nanoparticles were biosynthesized by microorganism through metabolism of gold precursor auric chloride into GNPs. The GNPs produced were characterized using UV–Vis spectrophotometer, SEM, DLS and EDAX. This work on nanoparticles synthesis offers a new approach to exploit marine water and thus shifting the usual trend from soil microbes to marine bacteria and its amenability for large-scale production.
Abstract: 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.
Pub.: 11 May '10, Pinned: 05 Oct '17
Abstract: During recent years investigation on the development of eco-friendly processes for production of gold nanoparticles (GNPs) have received much attention due to hazardous effects of chemical compounds used for nanoparticle preparation. In the present study, the purified laccase from Paraconiothyrium variabile was applied for synthesis of Au nanoparticles (AuNPs) and the properties of produced nanoparticles were characterized. The UV-vis spectrum of formed AuNPs showed a peak at 530 nm related to surface plasmon absorbance of GNPs represented the formation of gold nanoparticles after 20 min incubation of HAuCl(4) (0.6 mM) in the presence of 73 U laccase at 70°C. Transmission electron microscopy (TEM) image of AuNPs showed well dispersed nanoparticles in the range of 71-266 nm as determined by the laser light scattering method. The pattern of energy dispersive X-ray (EDX) of the prepared GNPs confirmed the structure of gold nanocrystals.
Pub.: 28 May '11, Pinned: 05 Oct '17
Abstract: Metal nanoparticles, in general, and gold nanoparticles, in particular, are very attractive because of their size- and shape-dependent properties. Biosynthesis of anisotropic gold nanoparticles using aqueous extract of Madhuca longifolia and their potential as IR blockers has been demonstrated. The tyrosine residue was identified as the active functional group for gold ion reduction. These gold nanoparticles were characterized by of UV-Vis spectrophotometer, FTIR, TEM and HrTEM. The presence of proteins was identified by FTIR, SDS-PAGE, UV-Vis and fluorescence spectroscopy. The micrograph revealed the formation of anisotropic gold nanoaprticles. The biologically synthesized gold nanotriangles can be easily coated in the glass windows which are highly efficient in absorbing IR radiations.
Pub.: 02 Aug '11, Pinned: 05 Oct '17
Abstract: The present study demonstrates an unprecedented green process for the production of spherical-shaped Au and Ag nanoparticles synthesized and stabilized using a bacterium, Brevibacterium casei. Aqueous solutions of chloroaurate ions for Au and Ag(+) ions for silver were treated with B. casei biomass for the formation of Au nanoparticles (AuNP) and Ag nanoparticles (AgNP). The nanometallic dispersions were characterized by surface plasmon absorbance measuring at 420 and 540 nm for Ag and Au nanoparticles, respectively. Transmission electron microscopy showed the formation of nanoparticles in the range of 10-50 nm (silver), and 10-50 nm (gold). XRD analysis of the silver and gold nanoparticles confirmed the formation of metallic silver and gold. Further analysis carried out by Fourier Transform Infrared Spectroscopy (FTIR), provides evidence for the presence of proteins as possible biomolecules responsible for the reduction and capping agent which helps in increasing the stability of the synthesized silver and gold nanoparticles. The biological activities of the synthesized particles were confirmed based on their stable anti-coagulant effects. The use of bacterium for nanoparticles synthesis offers the benefits of ecofriendliness and amenability for large-scale production.
Pub.: 04 Mar '10, Pinned: 05 Oct '17
Abstract: The growing trend of exploring bacteria, fungi, actinomycetes and plant materials for the biosynthesis of nanoparticles is considered as eco friendly and a green technological approach. In this backdrop the present study reports the synthesis of gold (Au) nanoparticles from gold precursor using the extract derived from the marine sponge, Acanthella elongata (Dendy, 1905) belonging to the primitive phylum Porifera. Water-soluble organics present in the marine sponge extract were mainly responsible for the reduction of gold ions to nano-sized Au particles. The sponge extract added to 10-3 M HAuCl4 aqueous solution at 45°C changed to pinkish ruby red color solution and confirm the bioreduction within 4 h with continuous stirring. UV-visible spectrum of the aqueous medium containing gold nanoparticles showed a peak around 526 nm. High-resolution transmission electron micrographs (HR-TEM) confirmed the monodispersed and spherical shaped with the size ranges from 7 to 20 nm, however a maximum number of particles were in 15 nm diameter. Through Fourier transform infrared spectroscopy (FT-IR) analysis, the reducing agent in the marine sponge extract was identified which is attributed for the biosynthesis of gold colloids. The XRD analysis respects the Bragg's law and confirmed the crystalline nature of the gold nanoparticles.
Pub.: 11 Sep '10, Pinned: 05 Oct '17