Fig. 4.

In vivo targeted PET imaging with SWCNTs. (a) Schematic illustration of the non-covalently functionalized SWCNT. The hydrophobic chains (blue segments) bind strongly to the sidewall of the SWCNT, and the PEG chains render water solubility. RGD peptide can allow for integrin α_vβ₃ targeting and DOTA molecules on the SWCNT can complex ⁶⁴Cu for PET imaging. (b) 2D projection of the PET images of U87MG tumor-bearing mice at 8 h post-injection of SWCNT-RGD without and with (denoted as “Block”) co-injection of an excess amount of RGD peptide, which demonstrated receptor specificity in vivo. The arrowheads indicate the tumors. (c) Raman spectra of tissue homogenate provided direct evidence of SWCNT presence in the tumor and the liver. (Reprinted with permission from ⁸⁷. © 2007 Nature Publishing Group.)