title: Near-infrared optical sensors based on single-walled carbon nanotubes.
abstract: 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.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois-Urbana/Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, USA.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Barone
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Baik
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Heller
authors.forename: Michael S
authors.initials: MS
authors.lastname: Strano
mesh_terms: D015374:Biosensing Techniques; D005453:Fluorescence; D005947:Glucose / Q000032:analysis*; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D055095:Optics and Photonics
chemical_list: D037742:Nanotubes, Carbon; D005947:Glucose