Metal nanoparticles synthesis: An overview on methods of preparation, advantages and disadvantages, and applications

Biosynthesis of cobalt oxide nanoparticles using endophytic fungus Aspergillus nidulans.

Selenium is an important component of human diet and a number of studies have declared its chemopreventive and therapeutic properties against cancer. However, very limited studies have been conducted about the properties of selenium nanostructured materials in comparison to other well-studied selenospecies. Here, we have shown that the anticancer property of biostabilized selenium nanorods (SeNrs) synthesized by applying a novel strain Ess_amA-1 of Streptomyces bikiniensis. The strain was grown aerobically with selenium dioxide and produced stable SeNrs with average particle size of 17 nm. The optical, structural, morphological, elemental, and functional characterizations of the SeNrs were carried out using techniques such as UV-vis spectrophotometry, transmission electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectrophotometry, respectively. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed that the biosynthesized SeNrs induces cell death of Hep-G2 and MCF-7 human cancer cells. The lethal dose (LD50%) of SeNrs on Hep-G2 and MCF-7 cells was recorded at 75.96 μg/mL and 61.86 μg/mL, respectively. It can be concluded that S. bikiniensis strain Ess_amA-1 could be used as renewable bioresources of biosynthesis of anticancer SeNrs. A hypothetical mechanism for anticancer activity of SeNrs is also proposed.

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Anticancer activity of biostabilized selenium nanorods synthesized by Streptomyces bikiniensis strain Ess_amA-1

Metal chalcogenide (metal sulfide, selenide and telluride) quantum dots (QDs) have attracted considerable attention due to their quantum confinement and size-dependent photoemission characteristics. QDs are one of the earliest products of nanotechnology that were commercialized for tracking macromolecules and imaging cells in life sciences. An array of physical, chemical and biological methods have been developed to synthesize different QDs. Biological production of QDs follow green chemistry principles, thereby use of hazardous chemicals, high temperature, high pressure and production of by-products is either minimized or completely avoided. In the past decade, significant progress has been made wherein a diverse range of living organisms, i.e. viruses, bacteria, fungi, microalgae, plants and animals have been explored for synthesis of all three types of metal chalcogenide QDs. However, better understanding of the biological mechanisms that mediate the synthesis of metal chalcogenides and control the growth of QDs is needed for improving their yield and properties as well as addressing issues that arise during scale-up. In this review, we present the current status of the biological synthesis and applications of metal chalcogenide QDs. Where possible, the role of key biological macromolecules in controlled production of the nanomaterials is highlighted, and also technological bottlenecks limiting widespread implementation are discussed. The future directions for advancing biological metal chalcogenide synthesis are presented.

Metal chalcogenide quantum dots: biotechnological synthesis and applications

Green synthesis of therapeutic nanoparticles: an expanding horizon

https://www.researchgate.net/profile/Raj_Mohan_Balakrishnan/publication/260990324_Biosynthesis_of_Lead_Selenide_quantum_rods_in_marine_Aspergillus_Terreus/links/02e7e533aaa049d4ab000000.pdf

Udaya Bhat Kumar

Papers

Biosynthesis of lead selenide quantum rods in marine Aspergillus terreus