Browsing by Author "Kuznetsov, Oleksandr"

Now showing 1 - 4 of 4
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    Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells
    (Springer, 2013) Corr, Stuart J.; Raoof, Mustafa; Cisneros, Brandon T.; Kuznetsov, Oleksandr; Massey, Katheryn; Kaluarachchi, Warna D.; Cheney, Matthew A.; Billups, Edward W.; Wilson, Lon J.; Curley, Steven A.; Richard E. Smalley Institute for Nanoscale Science and Technology
    Highly exfoliated sulfonated graphene sheets (SGSs), an alternative to graphene oxide and graphene derivatives, were synthesized, characterized, and applied to liver cancer cells in vitro. Cytotoxicity profiles were obtained using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, WST-1[2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, and lactate dehydrogenase release colorimetric assays. These particles were found to be non-toxic across the concentration range of 0.1 to 10 μg/ml. Internalization of SGSs was also studied by means of optical and electron microscopy. Although not conclusive, high-resolution transmission and scanning electron microscopy revealed variant internalization behaviors where some of the SGS became folded and compartmentalized into tight bundles within cellular organelles. The ability for liver cancer cells to internalize, fold, and compartmentalize graphene structures is a phenomenon not previously documented for graphene cell biology and should be further investigated.
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    Functionalization of carbon nanomaterials for biomedical and nanocomposite applications
    (2010) Kuznetsov, Oleksandr; Khabashesku, Valery N.
    New derivatives of carbon nanostructures: nanotubes, nano-onions and nanocrystalline diamonds were obtained through fluorination and subsequent functionalization with sucrose. Chemically modified nanocarbons show high solubility in water, ethanol, DMF and can be used as biomaterials for medical applications. It was demonstrated that sucrose functionalized nanostructures can find applications in nanocomposites due to improved dispersion enabled by polyol functional groups. Additionally, pristine and chemically derivatized carbon nanotubes were studied as nanofillers in epoxy composites. Carbon nanotubes tailored with amino functionalities demonstrated better dispersion and crosslinking with epoxy polymer yielding improved tensile strength and elastic properties of nanocomposites.
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    Functionalization of Nanocarbons for Composite, Biomedical and Sensor Applications
    (2013-07-24) Kuznetsov, Oleksandr; Billups, W. Edward; Hauge, Robert H.; Rau, Carl
    New derivatives of carbon nanostructures: nanotubes, nano-onions and nanocrystalline diamonds were obtained through fluorination and subsequent functionalization with sucrose. Chemically modified nanocarbons show high solubility in water, ethanol, DMF and can be used as biomaterials for medical applications. It was demonstrated that sucrose functionalized nanostructures can find applications in nanocomposites due to improved dispersion enabled by polyol functional groups. Additionally, pristine and chemically derivatized carbon nanotubes were studied as nanofillers in epoxy composites. Carbon nanotubes tailored with amino functionalities demonstrated better dispersion and crosslinking with epoxy polymer yielding improved tensile strength and elastic properties of nanocomposites. Reductive functionalization of nanocarbons, also known as Billups reaction, is a powerful method to yield nanomaterials with high degree of surface functionalization. In this method, nanocarbon salts prepared by treatment with lithium or sodium in liquid ammonia react readily with alkyl and aryl halides as well as bromo carboxylic acids. Functionalized materials are soluble in various organic or aqueous solvents. Water soluble nanodiamond derivatives were also synthesized by reductive functionalization of annealed nanodiamonds. Nanodiamond heat pretreatment was necessary to yield surface graphene layers and facilitate electron transfer from reducing agent to the surface of nanoparticles. Other carbon materials such as activated carbon and anthracite coal were also derivatized using reductive functionalization to yield water soluble activated carbon and partially soluble in organic solvents anthracite. It was shown that activated carbon can be effectively functionalized by Billups method. New derivatives of activated carbon can improve water treatment targeting specific impurities and bio active contaminants. It was demonstrated that functionalized carbon nanotubes are suitable for real time radiation measurements. Radiation sensor incorporating derivatized carbon nanotubes is lightweight and reusable. In summary, functionalization of carbon nanomaterials opens new avenues for processing and applications ranging from biomedicine to radiation sensing in space.
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    Polyol functionalized water soluble carbon nanostructures
    (2013-04-16) Khabashesku, Valery N.; Kuznetsov, Oleksandr; Lobo, Rui; Rice University; United States Patent and Trademark Office
    A method of making a water soluble carbon nanostructure includes treating a fluorinated carbon nanostructure material with a polyol in the presence of a base. A water soluble carbon nanostructure comprises a fluorinated carbon nanostructure covalently bound to a polyol. Exemplary uses of water soluble carbon nanostructures include use in polymer composites, biosensors and drug delivery vehicles.