Single-walled carbon nanotubes (SWNTs) functionalized with -COOH (along with some sulphonation and nitration), and/or modified with chitosan were prepared and tested for their singlet oxygen ((1)O(2)) production. The emission from (1)O(2) observed upon SWNT irradiation at 532 nm was due to a two-photon process, while (1)O(2) production via excitation at 355 nm occurred through a conventional one-photon pathway. The relative quantum yield of (1)O(2) production at excitation wavelength of 532 nm was found to be 0.00, 0.07-0.13 and 0.24-0.54 for highly-functionalized, partially-functionalized and non-functionalized SWNT samples respectively. The nanotube-mediated generation of (1)O(2) may find applications in both targeted destruction of tumor cells and selective degradation of drug molecules. Our research provides a practical approach to modulate the production of reactive oxygen species from SWNTs via surface functionalization/modification.
The Journal of Physical Chemistry C 04/2009; 113(13):5182-8185. DOI:10.1021/jp809268q · 4.84 Impact Factor