Browsing by Author "Narayanan, Tharangattu N."

Now showing 1 - 6 of 6
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    3D Macroporous Solids from Chemically Cross-linked Carbon Nanotubes
    (Wiley, 2014) Ozden, Sehmus; Narayanan, Tharangattu N.; Tiwary, Chandra S.; Dong, Pei; Hart, Amelia H.C.; Vajtai, Robert; Ajayan, Pulickel M.
    Suzuki reaction for covalently interconnected 3D carbon nanotube (CNT) architectures is reported. The synthesis of 3D macroscopic solids made of CNTs covalently connected via Suzuki cross-coupling, a well-known carbon-carbon covalent bond forming reaction in organic chemistry, is scalable. The resulting solid has a highly porous, interconnected structure of chemically cross-linked CNTs. Its use for the removal of oil from contaminated water is demonstrated.
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    Bifunctional Luminomagnetic Rare-Earth Nanorods for High-Contrast Bioimaging Nanoprobes
    (Springer Nature, 2016) Gupta, Bipin Kumar; Singh, Satbir; Kumar, Pawan; Lee, Yean; Kedawat, Garima; Narayanan, Tharangattu N.; Vithayathil, Sajna Antony; Ge, Liehui; Zhan, Xiaobo; Gupta, Sarika; Martí, Angel A.; Vajtai, Robert; Ajayan, Pulickel M.; Kaipparettu, Benny Abraham
    Nanoparticles exhibiting both magnetic and luminescent properties are need of the hour for many biological applications. A single compound exhibiting this combination of properties is uncommon. Herein, we report a strategy to synthesize a bifunctional luminomagnetic Gd2−xEuxO3 (x = 0.05 to 0.5) nanorod, with a diameter of ~20 nm and length in ~0.6 μm, using hydrothermal method. Gd2O3:Eu3+ nanorods have been characterized by studying its structural, optical and magnetic properties. The advantage offered by photoluminescent imaging with Gd2O3:Eu3+ nanorods is that this ultrafine nanorod material exhibits hypersensitive intense red emission (610 nm) with good brightness (quantum yield more than 90%), which is an essential parameter for high-contrast bioimaging, especially for overcoming auto fluorescent background. The utility of luminomagnetic nanorods for biological applications in high-contrast cell imaging capability and cell toxicity to image two human breast cancer cell lines T47D and MDA-MB-231 are also evaluated. Additionally, to understand the significance of shape of the nanostructure, the photoluminescence and paramagnetic characteristic of Gd2O3:Eu3+ nanorods were compared with the spherical nanoparticles of Gd2O3:Eu3+.
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    Fluorinated Graphene Oxide: a New Multimodal Material for Biological Applications
    (Wiley, 2013) Romero-Aburto, Rebeca; Narayanan, Tharangattu N.; Nagaoka, Yutaka; Hasumura, Takashi; Mitcham, Trevor M.; Fukuda, Takahiro; Cox, Paris J.; Bouchard, Richard R.; Maekawa, Toru; Kumar, Sakthi; Torti, Suzy V.; Mani, Sendurai A.; Ajayan, Pulickel M.
    Fluorinated graphene oxide (FGO) is reported for the first time as a magnetically responsive drug carrier that can serve as a MRI and photoacoustic contrast agent, under pre-clinical settings, as well as a photothermal therapy Its hydrophilic nature facilitates biocompatibility. FGO as a broad wavelength absorber, with high charge transfer and strong nonlinear scattering is optimal for NIR laser-induced hyperthermia.
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    Graphene–protein field effect biosensors: glucose sensing
    (Elsevier, 2015) Viswanathan, Sowmya; Narayanan, Tharangattu N.; Aran, Kiana; Fink, Kathryn D.; Paredes, Jacobo; Ajayan, Pulickel M.; Filipek, Slawomir; Miszta, Przemyslaw; Tekin, H. Cumhur; Inci, Fatih; Demirci, Utkan; Li, Pingzuo; Bolotin, Kirill I.; Liepmann, Dorian; Renugopalakrishanan, V.
    Chronic diseases are becoming more prevalent, and the complexities of managing patients continue to escalate, since their care must be balanced between the home and clinical settings. Diabetes is the most advanced example, where self-monitoring has been shown to be necessary. Glucometers are point-of-care (POC) devices that have become standard platforms at home and clinical settings. Similarly, many other POC biosensors have also been developed. Enzymes are often used in these sensors because of their specificity and the reaction products can be electrochemically transduced for the measurement. When enzymes are immobilized to an electronically active substrate, enzymatic reactions can be transduced by direct electron transport. This paper describes an approach for the development of graphene-based POC devices. This includes modifying enzymes for improved performance, developing methods to bind them to the graphene surface, incorporation of the functionalized graphene on a field-effect transistor (FET), and integration into a microfluidic device suitable for home use. This paper describes an approach for the development of a graphene-based POC biosensor platform using glucose as an example of target molecule.
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    Hybrid 2D Nanomaterials as Dual-mode Contrast Agents in Cellular Imaging
    (Wiley-VCH Verlag, 2012) Narayanan, Tharangattu N.; Gupta, Bipin K.; Vithayathil, Sajna A.; Aburto, Rebeca R.; Mani, Sendurai A.; Taha-Tijerina, Jaime; Xie, Bin; Kaipparettu, Benny A.; Torti, Suzy V.; Ajayan, Pulickel M.
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    Structural determination of Enzyme-Graphene Nanocomposite Sensor Material
    (Springer Nature, 2019) Rai, Durgesh K.; Gurusaran, Manickam; Urban, Volker; Aran, Kiana; Ma, Lulu; Qian, Shuo; Narayanan, Tharangattu N.; Ajayan, Pulickel M.; Liepmann, Dorian; Sekar, Kanagaraj; Álvarez-Cao, María-Efigenia; Escuder-Rodríguez, Juan-José; Cerdán, María-Esperanza; González-Siso, María-Isabel; Viswanathan, Sowmya; Paulmurugan, Ramasamy; Renugopalakrishnan, Venkatesan; Li, Pingzuo
    State-of-the-art ultra-sensitive blood glucose-monitoring biosensors, based on glucose oxidase (GOx) covalently linked to a single layer graphene (SLG), will be a valuable next generation diagnostic tool for personal glycemic level management. We report here our observations of sensor matrix structure obtained using a multi-physics approach towards analysis of small-angle neutron scattering (SANS) on graphene-based biosensor functionalized with GOx under different pH conditions for various hierarchical GOx assemblies within SLG. We developed a methodology to separately extract the average shape of GOx molecules within the hierarchical assemblies. The modeling is able to resolve differences in the average GOx dimer structure and shows that treatment under different pH conditions lead to differences within the GOx at the dimer contact region with SLG. The coupling of different analysis methods and modeling approaches we developed in this study provides a universal approach to obtain detailed structural quantifications, for establishing robust structure-property relationships. This is an essential step to obtain an insight into the structure and function of the GOx-SLG interface for optimizing sensor performance.