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Quenching of Single-Walled Carbon Nanotube Fluorescence by Dissolved Oxygen Reveals Selective Single-Stranded DNA
Yu Zheng1, Sergei M Bachilo1, R Bruce Weisman1
1Department of Chemistry and the Smalley-Curl Institute and ‡Department of Materials Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States.
Abstract:
The selective interactions between short oligomers of single-stranded DNA (ssDNA) and specific structures of single-walled carbon nanotubes have been exploited in powerful methods for nanotube sorting. We report here that nanotubes coated with ssDNA also display selective interactions through the selective quenching of nanotube fluorescence by dissolved oxygen. In aqueous solutions equilibrated under 1 atm of O2, emission intensity from semiconducting nanotubes is reduced by between 9 and 40%, varying with the combination of ssDNA sequence and nanotube structure. This quenching reverses promptly and completely on the removal of dissolved O2 and may be due to physisorption on nanotube surfaces. Fluorescence quenching offers a simple, nondestructive approach for studying the structure-selective interactions of ssDNA with single-walled carbon nanotubes and identifying recognition sequences.