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Research Letters in Nanotechnology
Volume 2008, Article ID 156358, 5 pages
Research Letter

Single-Walled Carbon Nanotubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

1Department of Chemical Engineering, New Mexico State University, P.O. Box 30001, MSC 3805, Las Cruces, NM 88003, USA
2Microbiology & Applied Biochemistry, Airbase Sciences Branch AFRL/RXQL, 139 Barnes Drive, Suite 2, Tyndall AFB, FL 32403, USA
3Department of Biology, University of South Carolina, Columbia, SC 29208, USA
4Research Technologies Section (RTB), Rocky Mountain Laboratories (NIAID, NIH), Hamilton, MT 59840, USA
5Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA

Received 6 March 2008; Accepted 25 April 2008

Academic Editor: Ram B. Gupta

Copyright © 2008 Venkata K. K. Upadhyayula et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The possibility of using single-walled carbon nanotubes (SWCNTs) aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k) for S.aureus and E.coli determined from batch adsorption study was found to be 9×108 and 2×108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.