Pharmacokinetics of RGD SWNTs (n = 3) and plain nontargeted SWNTs (n = 3) in the tumor of nude mice over time. Notice the accumulation of RGD nanotubes (gray diamonds) in the tumor slightly increases over time remaining within the tumor area. Plain nanotubes (open-faced squares) appear to initially arrive in the tumor with a rapid decrease after 20 min postinjection. Data are presented as mean ± standard error, and * indicates p < 0.05.

Raman spectral analysis of RGD nanotubes and plain nontargeted nanotubes within the tumor over three days post injection (error bars represent s.e.m.). The graphed data show a significant difference (* indicates p < 0.05) between mice injected with RGD nanotubes and mice injected with plain nanotubes at all time points post injection.

Raman spectrum acquired from in vivo (red) and ex-vivo (green) tumors at 72 h in both experimental and control groups of mice. Notice how the g-band Raman peak (arrow ~ 1593 cm⁻¹) is prominently pronounced in the experimental group where mice received RGD conjugated nanotubes. Conversely, there is no g-band Raman peak associated with the nanotubes seen in either the in vivo (blue) or ex-vivo (purple) tumors taken from the mice that received nontargeted plain nanotubes. The spectrums given from the control mice resemble the background spectrum (light blue) taken of the tumors before nanotube injection.

Raster-scan images of tumor area (750 μm steps) using Raman spectroscopy in conjunction with SWNTs. The grayscale bar to the right depicts the Raman intensity where white represents the maximum intensity and black represents no intensity. (a), Digital photograph of tumor bearing mouse depicting tumor area scanned with Raman spectroscopy (black box). (b), Panel of tumor maps from mouse receiving RGD nanotubes at various time points post injection starting from left to right with 2, 8, 24, 48, and 72 h. (c), Panel of tumor maps from mouse receiving plain nanotubes at various time points post injection starting from left to right with 2, 8, 24, 48, and 72 h. Notice how the panel of tumor maps in panel b from the mouse that received RGD nanotubes shows a continued accumulation of nanotubes in the tumor area over 72 h, as opposed to panel c which shows no defined accumulation of nanotubes in the tumor area of a mouse that received plain nanotubes.

Raman spectral analysis comparing accumulation of RGD nanotubes within the tumor area on the right shoulder and the contralateral left shoulder (no tumor) of nude mice (error bars represent s.e.m.). Notice the significant increase (* indicates p < 0.05) of RGD nanotube accumulation within the tumor area as opposed to the contralateral shoulder at all time points over three days.

Raman spectral analysis of RGD and plain nanotube accumulation within various tissues from experimental and control mice (error bars represent s.e.m.). (a), Raman data of various excised tissues at 72 h post nanotube injection. Excised tumor data shows more accumulation of RGD nanotubes within tumor tissue than plain nanotubes at 72 h, supporting in vivo data shown previously. The graph also depicts more accumulation of plain nanotubes within the excised liver and spleen in comparison to the mice that received RGD conjugated nanotubes. (b), In-vivo Raman data of RGD nanotubes and plain nontargeted nanotubes within the liver over three days post injection. Notice how the 72 h time point shows roughly twice as much nanotube accumulation in the liver of mice receiving plain nanotubes, correlating with the 72 h ex-vivo data in panel a. Significant differences in nanotube accumulation within the liver were observed at 24 and 72 h post injection with a p < 0.05 depicted with *. Very little Raman signal was seen throughout the control group; therefore a y-axis break was placed between 1 and 0.04 to visualize lower nanotube concentration in tumors of mice receiving plain nanotubes.