High Performance In Vivo Near-IR (>1 {\mu}m) Imaging and Photothermal Cancer Therapy with Carbon Nanotubes

TL;DR

This study demonstrates the use of functionalized single-walled carbon nanotubes for effective in vivo near-infrared tumor imaging and photothermal therapy, achieving complete tumor elimination with lower doses and power than gold nanorods.

Contribution

First dual application of SWNTs for in vivo tumor imaging and photothermal therapy at low doses with high efficacy and minimal toxicity.

Findings

Successful tumor imaging in the 1.0-1.4 μm emission region.

Complete tumor elimination in mice without toxic side effects.

SWNTs outperform gold nanorods at lower doses and power levels.

Abstract

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.