@article { ISI:000229118100006, title = {Extracellular biosynthesis of bimetallic Au-Ag alloy nanoparticles}, journal = {Small}, volume = {1}, number = {5}, year = {2005}, month = {MAY}, pages = {517-520}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, keywords = {alloys, Biosynthesis, composites, enzymes, Nanoparticles}, issn = {1613-6810}, doi = {10.1002/smll.200400053}, author = {Senapati, S. and Ahmad, Absar and Khan, Mohammad Islam and Sastry, M. and Kumar, R.} } @article { ISI:000205747600006, title = {Extra-/intracellular biosynthesis of gold nanoparticles by an alkalotolerant fungus, trichothecium sp.}, journal = {Journal of Biomedical Nanotechnology}, volume = {1}, number = {1}, year = {2005}, month = {MAR}, pages = {47-53}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

The development of reliable, eco-friendly processes for the synthesis of nanoscale materials is an important aspect of nanotechnology. As part of our ongoing investigation into the use of fungi for nanoparticle synthesis, we report herein that depending on the reaction conditions of the fungus Trichothecium sp. with aqueous gold ions, gold nanoparticle synthesis can be controlled to occur either within the biomass or extracellularly. Moreover, we have found that reaction of gold ions with the Trichothecium sp. fungal biomass under stationary conditions results in the rapid extracellular formation of gold nanoparticles of spherical, rod-like and triangular morphology whereas reaction of the biomass under shaking conditions resulted in intracellular growth of the nanoparticles. It is believed that on changing the reaction conditions of the fungus with gold ions, the enzymes and proteins which are being released into the medium under stationary conditions do not get released under shaking conditions resulting in the formation of extracellular or intracellular gold nanoparticles respectively. The gold nanoparticles are not toxic to the cells and the cells continued to grow after the biosynthesis of the gold nanoparticles in both the cases.

}, keywords = {Biosynthesis, enzymes, Fungus, Gold, Morphology Control, Nanoparticles}, issn = {1550-7033}, doi = {10.1166/jbn.2005.012}, author = {Ahmad, Absar and Senapati, Satyajyoti and Khan, Mohammad Islam and Kumar, Rajiv and Sastry, Murali} } @article { ISI:000306045000005, title = {Extracellular biosynthesis of platinum nanoparticles using the fungus fusarium oxysporum}, journal = {Colloids and Surfaces B-Biointerfaces}, volume = {97}, year = {2012}, month = {SEP}, pages = {27-31}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Nanoscience is a blooming field and promises a better future. In order to fabricate nanoparticles in an eco-friendly and inexpensive manner, significant efforts are being made to replace the chemical and physical methods currently being used with the biological methods. Chemical methods are toxic while the physical ones are very expensive. Biological methods, apart from being cost-effective, also provide protein capped nanoparticles which are thus very stable, have good dispersity and do not flocculate, and may find use in various applications. The present work emphasizes on platinum nanoparticles synthesis protocol which occurs at ambient conditions. The fungus Fusarium oxysporum when incubated with hexachloroplatinic acid (H2PtCl6) in ambient conditions reduces the precursor and leads to the formation of stable extracellular platinum nanoparticles. The biosynthesis of platinum nanoparticles was monitored by UV-visible spectroscopy and these nanoparticles were completely characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The nanoparticles are in the size range of 5-30 nm and are stabilized by proteins present in the solution. The reduction process is believed to occur enzymatically, thus creating the possibility of a rational, fungal-based method for the synthesis of nanoparticles over a wide range of chemical compositions. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {Biosynthesis, Fungus, Nanoparticles, platinum}, issn = {0927-7765}, doi = {10.1016/j.colsurfb.2012.03.026}, author = {Syed, Asad and Ahmad, Absar} } @article { ISI:000317836000016, title = {Extra- and intracellular gold nanoparticles synthesis using live peanut callus cells}, journal = {Current Nanoscience}, volume = {9}, number = {1}, year = {2013}, month = {FEB}, pages = {107-112}, publisher = {BENTHAM SCIENCE PUBL LTD}, address = {EXECUTIVE STE Y-2, PO BOX 7917, SAIF ZONE, 1200 BR SHARJAH, U ARAB EMIRATES}, abstract = {

An important challenge of considerable topical significance in nanotechnology is the development of eco-friendly experimental processes for the synthesis of nanomaterials in large quantities with variable sizes, shapes and chemical compositions. Green synthesis routes for the production of inorganic metal nanoparticles using whole cell of microorganisms and plant extracts are gaining tremendous popularity as these are non-toxic, cheap and occur at ambient conditions. The present work emphasizes on gold nanoparticles synthesis protocol using live plant callus cells. Peanut callus cells when incubated with HAuCl4 solution in ambient conditions reduced the precursor and lead to formation of well dispersed, water soluble extracellular and intracellular gold nanoparticles within 24 hours. The biosynthesis of gold nanoparticles was monitored by UV-visible spectroscopy (UV-Vis) and further characterized by X-ray diffraction analysis (XRD), Energy Dispersive Spectroscopy (EDS) and Selected Area Electron Diffraction (SAED). The particle size distribution shows that the average particle size is 50 nm for extra-and 31 nm for intracellular gold nanoparticles. The nanoparticles may be stabilized by proteins secreted by callus cells. The reduction process is believed to occur enzymatically, thus creating the possibility of a rational, plant cell-based method for the synthesis of nanoparticles over a wide range of chemical compositions.

}, keywords = {Biosynthesis, callus, gold nanoparticles, live cells, Peanut, TEM}, issn = {1573-4137}, author = {Raju, D. and Mehta, Urmil J. and Ahmad, Absar} } @article { ISI:000317545600006, title = {Extracellular biosynthesis of CdTe quantum dots by the fungus fusarium oxysporum and their anti-bacterial activity}, journal = {Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy}, volume = {106}, year = {2013}, month = {APR}, pages = {41-47}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The growing demand for semiconductor [quantum dots (Q-dots)] nanoparticles has fuelled significant research in developing strategies for their synthesis and characterization. They are extensively investigated by the chemical route; on the other hand, use of microbial sources for biosynthesis witnessed the highly stable, water dispersible nanoparticles formation. Here we report, for the first time, an efficient fungal-mediated synthesis of highly fluorescent CdTe quantum dots at ambient conditions by the fungus Fusarium oxysporum when reacted with a mixture of CdCl2 and TeCl4. Characterization of these biosynthesized nanoparticles was carried out by different techniques such as Ultraviolet-visible (UV-Vis) spectroscopy, Photoluminescence (PL), X-ray Diffraction (XRD), X-ray Photoelectron spectroscopy (XPS), Transmission Electron Microscopy (TEM) and Fourier Transformed Infrared Spectroscopy (FTIR) analysis. CdTe nanoparticles shows antibacterial activity against Gram positive and Gram negative bacteria. The fungal based fabrication provides an economical, green chemistry approach for production of highly fluorescent CdTe quantum dots. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {antibacterial activity, Biosynthesis, CdTe, Fungus, Nanoparticles}, issn = {1386-1425}, doi = {10.1016/j.saa.2013.01.002}, author = {Syed, Asad and Ahmad, Absar} } @article { ISI:000330241000054, title = {Enzyme mediated synthesis of water-dispersible, naturally protein capped, monodispersed gold nanoparticles; their characterization and mechanistic aspects}, journal = {RSC Advances}, volume = {4}, number = {15}, year = {2014}, month = {JUL}, pages = {7729-7734}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Inorganic nanomaterials are conventionally synthesized under harsh environments like extremes of temperature, pressure and pH. These methods are eco-unfriendly, expensive, toxic, cumbersome, yield bigger particles which agglomerate due to not being capped by capping agents. In contrast, biological synthesis of inorganic nanomaterials occurs under ambient conditions viz. room temperature, atmospheric pressure, physiological pH and is reliable, eco-friendly and cheap. We have already reported the extracellular biosynthesis of monodispersed gold nanoparticles from the whole cells of novel extremophilic actinomycete Thermomonospora sp. In order to know the exact mechanism of synthesis, we decided to investigating it further. Here we describe the simple protocol for purification of the temperature and SDS resistant sulfite reductase enzyme and organic capping molecule, which are required for the synthesis and stabilization of gold nanoparticles respectively. This purified enzyme was then employed for the synthesis of gold nanoparticles along with the capping molecule, which render gold nanoparticles monodispersed in solution.

}, issn = {2046-2069}, doi = {10.1039/c3ra43888k}, author = {Khan, Shadab Ali and Ahmad, Absar} } @article { ISI:000332782600001, title = {Extracellular biosynthesis of gadolinium oxide (Gd2O3) nanoparticles, their biodistribution and bioconjugation with the chemically modified anticancer drug taxol}, journal = {Beilstein Journal of Nanotechnology}, volume = {5}, year = {2014}, month = {MAR}, pages = {249-257}, publisher = {BEILSTEIN-INSTITUT}, type = {Article}, address = {TRAKEHNER STRASSE 7-9, FRANKFURT AM MAIN, 60487, GERMANY}, abstract = {

As a part of our programme to develop nanobioconjugates for the treatment of cancer, we first synthesized extracellular, protein-capped, highly stable and well-dispersed gadolinium oxide (Gd2O3) nanoparticles by using thermophilic fungus Humicola sp. The biodistribution of the nanoparticles in rats was checked by radiolabelling with Tc-99m. Finally, these nanoparticles were bioconjugated with the chemically modified anticancer drug taxol with the aim of characterizing the role of this bioconjugate in the treatment of cancer. The biosynthesized Gd2O3 nanoparticles were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). The Gd2O3-taxol bioconjugate was confirmed by UV-vis spectroscopy and fluorescence microscopy and was purified by using high performance liquid chromatography (HPLC).

}, keywords = {bioconjugation, biodistribution, gadolinium oxide, humicola sp, transmission electron microscopy}, issn = {2190-4286}, doi = {10.3762/bjnano.5.27}, author = {Khan, Shadab Ali and Gambhir, Sanjay and Ahmad, Absar} } @article { ISI:000340292800014, title = {Extracellular biosynthesis of metal sulfide nanoparticles using the fungus fusarium oxysporum}, journal = {Current Nanoscience}, volume = {10}, number = {4}, year = {2014}, month = {JUL}, pages = {588-595}, publisher = {BENTHAM SCIENCE PUBL LTD}, address = {EXECUTIVE STE Y-2, PO BOX 7917, SAIF ZONE, 1200 BR SHARJAH, U ARAB EMIRATES}, abstract = {

The development of reliable, eco-friendly processes for the synthesis of nanomaterials is an important aspect of nanotechnology. One approach that shows immense potential is based on the biosynthesis of nanoparticles using microorganisms such as bacteria. In this report, we demonstrate the extracellular biosynthesis and complete characterization of metal sulfide (PbS, ZnS, MnS and NiS) nanoparticles using fungus, Fusarium oxysporum. We observed that the exposure of aqueous solution of 1 mM metal sulfate to fungus Fusarium oxysporum resulted in the formation of highly stable technologically important metal sulfide semiconductor nanoparticles. Fusarium oxysporum synthesizes lead sulfide and zinc sulfide nanoparticles of fractal type structure whereas manganese sulfide and nickel sulfide nanoparticles are of variable polydispersed morphology. The variable morphology may be due to the dissimilar interaction of metal sulfide nanoparticles with capping proteins secreted by the fungus in solution. The nanoparticles solution is found to be extremely stable with little evidence of aggregation even after a month of storage. The long term stability of the nanoparticles is due to the proteins secreted by fungus in the nanoparticle solution which bind to the surface of the nanoparticles and thus prevent aggregation.

}, keywords = {Biosynthesis, enzymes, fungi, metal sulfide, Nanoparticles}, issn = {1573-4137}, author = {Senapati, Satyajyoti and Syed, Asad and Khan, Shadab and Pasricha, Renu and Khan, Mohammad Islam and Kumar, Rajiv and Ahmad, Absar} } @article {43962, title = {Effective degradation of organic water pollutants by atmospheric non-thermal plasma torch and analysis of degradation process}, journal = {Chemosphere}, volume = {167}, year = {2017}, month = {JAN}, pages = {396-405}, type = {Article}, abstract = {The paper reports the use of atmospheric non-thermal plasma torch as a catalyst for degradation of various organic pollutants dissolved in water. A flow of He mixed with air was used to produce the dielectric barrier discharge (DBD), at the tip of the torch, using pulsed electric excitation at 12 kV. The torch, operated at a power of 750 mW/mm{\texttwosuperior}, was seen to completely degrade the aqueous solutions of the pollutants namely methylene blue (MB), methyl orange (MO) and rhodamine-B (RB), at around 10$^{-}$$^{4}$ M concentrations, the concentration of polluants is one order higher than of routinely used heterogeneous photocatalytic reactions, within 10 min of irradiation time at room temperature. UV Visible spectra of the organic dye molecules, monitored after different intervals of plasma-irradiation, ranging between 1 and 10 min, have been used as tools to quantify their sequential degradation. Further, instead of using He, only air was used to form plasma plume and used for degradation of organic dye which follow similar trend as that of He plasma. Further, Liquid Chromatography Mass Spectroscopy (LCMS) technique has been used to understand degradation pathway of methylene blue (MB) as a representative case. Total organic carbon (TOC) measurements indicates significant decrease in its content as a function of duration of plasma exposure onto methylene blue as a representative case. Toxicity studies were carried out onto Gram negative Escherichia coli. This indicated that methylene blue, without plasma treatment, shows growth inhibition, whereas with plasma treatment no inhibition was observed.}, doi = {10.1016/j.chemosphere.2016.09.089}, author = {Bansode, Avinash H. and More, Supriya Eknath and Siddiqui, Ejaz Ahmad and Satpute, Shruti and Ahmad, Absar and Bhoraskar, Sudha V. and Mathe, Vikas L.} }