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Nat Mater. 2005 Jan;4(1):86-92. Epub 2004 Dec 12.

Near-infrared optical sensors based on single-walled carbon nanotubes.

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Department of Chemical and Biomolecular Engineering, University of Illinois-Urbana/Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, USA.


Molecular detection using near-infrared light between 0.9 and 1.3 eV has important biomedical applications because of greater tissue penetration and reduced auto-fluorescent background in thick tissue or whole-blood media. Carbon nanotubes have a tunable near-infrared emission that responds to changes in the local dielectric function but remains stable to permanent photobleaching. In this work, we report the synthesis and successful testing of solution-phase, near-infrared sensors, with beta-D-glucose sensing as a model system, using single-walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules. New types of non-covalent functionalization using electron-withdrawing molecules are shown to provide sites for transferring electrons in and out of the nanotube. We also show two distinct mechanisms of signal transduction-fluorescence quenching and charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.

[Indexed for MEDLINE]

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