@article { ISI:000230220900008, title = {Bacterial aerobic synthesis of nanocrystalline magnetite}, journal = {Journal of the American Chemical Society}, volume = {127}, number = {26}, year = {2005}, month = {JUL}, pages = {9326-9327}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, issn = {0002-7863}, doi = {10.1021/ja0508469}, author = {Bharde, Atul A. and Wani, A. and Shouche, Y. and Joy, Pattayil Alias and Bhagavatula L. V. Prasad and Sastry, M.} } @article { ISI:000227414900003, title = {Biological synthesis of stable vaterite crystals by the reaction of calcium ions with germinating chickpea seeds}, journal = {Crystal Growth \& Design}, volume = {5}, number = {2}, year = {2005}, month = {MAR}, pages = {399-402}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The total biological synthesis of CaCO3 crystals of the metastable vaterite polymorph at room temperature by simple protein-mediated reaction of aqueous Ca2+ ions with the CO2 generated during the root growth from germinating chickpea (Cicer arietinum) seeds is described. Highly stable vaterite crystals of spherical morphology are obtained, indicating that the proteins secreted from the roots during growth play a crucial role in stabilizing and directing the crystal growth.

}, issn = {1528-7483}, doi = {10.1021/cg0341858}, author = {Rautaray, D. and Sanyal, A. and Bharde, Atul A. and Ahmad, Absar and Sastry, M.} } @article { ISI:000252511300020, title = {Bacterial enzyme mediated biosynthesis of gold nanoparticles}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {7}, number = {12}, year = {2007}, month = {DEC}, pages = {4369-4377}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

Development of synthesis methods for anisotropic metal nanoparticles is of considerable interest due to their remarkable optoelectronic properties. Various shapes ranging from rods to cubes to tetrapods and prisms may be obtained by chemical methods. Here we show that anisotropic gold nanoparticles can be synthesized biologically by the bacterium Actinobacter spp. when challenged with gold chloride in the presence of Bovine serum albumin (BSA). We also observed that synthesis of gold nanoparticles occur with simultaneous induction of the protease enzyme secreted by the bacterium in the presence of BSA. The presence of BSA helps to enhance the rate of gold nanoparticles biosynthesis and may also impart some shape control. Controlling simple experimental conditions like incubation temperature and presence or absence of oxygen have drastic effect on the reaction rate and the morphology of the particles. Various assay experiments show that the presence of enzyme protease can act as a reducing as well as shape directing agent.

}, keywords = {Biosynthesis, bovine serum, gold nanoparticles}, issn = {1533-4880}, doi = {10.1166/jnn.2007.891}, author = {Bharde, Atul A. and Kulkarni, Aarohi and Rao, Mala and Prabhune, Asmita and Sastry, Murali} } @article { ISI:000256232900024, title = {Bacteria-mediated precursor-dependent biosynthesis of superparamagnetic iron oxide and iron sulfide nanoparticles}, journal = {Langmuir}, volume = {24}, number = {11}, year = {2008}, month = {JUN}, pages = {5787-5794}, publisher = {AMER CHEMICAL SOC}, type = {Article}, chapter = { }, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The bacterium Actinobacter sp. has been shown to be capable of extracellularly synthesizing iron based magnetic nanoparticles, namely maghemite (gamma-Fe2O3) and greigite (Fe3S4) Under ambient conditions depending on the nature of precursors used. More precisely, the bacterium synthesized maghemite when reacted with ferric chloride and iron sulfide when exposed to the aqueous solution of ferric chloride-ferrous sulfate. Challenging the bacterium with different metal ions resulted in induction of different proteins, which bring about the specific biochemical transformations in each case leading to the observed products. Maghemite and iron sulfide nanoparticles show superparamagnetic characteristics as expected. Compared to the earlier reports of magnetite and greigite synthesis by magnetotactic bacteria and iron reducing bacteria, which take place strictly under anaerobic conditions, the present procedure offers significant advancement since the reaction occurs under aerobic condition. Moreover, reaction end products can be tuned by the choice of precursors used.

}, issn = {0743-7463}, doi = {10.1021/la704019p}, author = {Bharde, Atul A. and Parikh, Rasesh Y. and Baidakova, Marina and Jouen, Samuel and Hannoyer, Beatrice and Enoki, Toshiaki and Bhagavatula L. V. Prasad and Shouche, Yogesh S. and Ogale, Satishchandra B. and Sastry, Murali} } @article {42680, title = {Bacterial synthesis of phtocatalytically active and biocompatible TiO2 and ZnO nanoparticles}, journal = {International Journal of Green Nanotechnology: Physics and Chemistry}, volume = {2}, year = {2010}, month = {DEC}, pages = {80-99}, abstract = {

TiO2 and ZnO nanoparticles are well known for their photocatalytic and ultraviolet (UV)-absorbent properties and have successfully entered into the market as consumer products. Large volume production of these nanoparticles by industries require environmentally friendly processes of synthesis. In this article, we show that when challenged with an appropriate precursor, the bacterium Actinobacter spp. can lead to the extracellular synthesis of ZnO and TiO2 nanoparticles. The biological way of synthesizing these materials probably leads to the in situ doping of elements like C, F, and N into their crystal lattices, which is evidenced by a red shift in the absorption edge. Because the doping is expected to affect the photocatalytic activity of these materials under different light conditions, such investigations have also been undertaken here. Further, the biocompatibility of these nanomaterials (cytotoxicity and genotoxicity) has also been investigated in detail.

}, keywords = {Biosynthesis, genotoxicity, Nanoparticles, Nanotoxicity, Photocatalysis}, doi = {10.1080/19430876.2010.532459}, author = {Singh, Sanjay and Britto, Virginia D. and Bharde, Atul A. and Sastry, Murali and Dhawan, Alok and Bhagavatula L. V. Prasad} }