  Short single-walled carbon nanotubes (SWNTs) functionalized by PEGylated
phospholipids are biologically non-toxic and long-circulating nanomaterials
with intrinsic near infrared photoluminescence (NIR PL), characteristic Raman
spectra, and strong optical absorbance in the near infrared (NIR). This work
demonstrates the first dual application of intravenously injected SWNTs as
photoluminescent agents for in vivo tumor imaging in the 1.0-1.4 {\mu}m
emission region and as NIR absorbers and heaters at 808 nm for photothermal
tumor elimination at the lowest injected dose (70 {\mu}g of SWNT/mouse,
equivalent to 3.6 mg/kg) and laser irradiation power (0.6 W/cm2) reported to
date. Ex vivo resonance Raman imaging revealed the SWNT distribution within
tumors at a high spatial resolution. Complete tumor elimination was achieved
for large numbers of photothermally treated mice without any toxic side effects
after more than six months post-treatment. Further, side-by-side experiments
were carried out to compare the performance of SWNTs and gold nanorods (AuNRs)
at an injected dose of 700 {\mu}g of AuNR/mouse (equivalent to 35 mg/kg) in NIR
photothermal ablation of tumors in vivo. Highly effective tumor elimination
with SWNTs was achieved at 10 times lower injected doses and lower irradiation
powers than for AuNRs. These results suggest there are significant benefits of
utilizing the intrinsic properties of biocompatible SWNTs for combined cancer
imaging and therapy.
