Evaluation of multiplexing experiment. (a) Raman spectrum acquired from first s.c. injection of S421 SERS nanoparticles. The software has assigned the color red for this particular Raman spectrum. (b) Raman spectrum acquired from second s.c. injection of S440 SERS nanoparticles. The software has assigned the color green for this particular Raman spectrum. (c) Raman spectrum acquired from the third s.c. injection of an equal mix of S421 and S440. Notice how this spectrum represents an equal mix of both individual spectrums as if they had been overlaid. As a result, the color yellow is calculated by the analysis software to represent an equal mix of the red (S421) and green (S440) SERS nanoparticles in the map at Right.

Pharmacokinetics of SERS nanoparticles and SWNTs in the liver [data acquisition starts at 10 s, zero accumulation at time point zero (data not shown)]. (a) Accumulation of nonpegylated SERS versus 5 kDa of PEG SERS nanoparticles in liver of nude mouse. The graph depicts the mean normalized concentration of SERS nanoparticles in three mice ± SEM. (b) Accumulation of nonpegylated SERS versus 20 kDa of PEG SERS nanoparticle in liver of nude mouse. The graph depicts the mean normalized concentration of SERS nanoparticles in three mice ± SEM. (c) Pharmacokinetics of nanotubes in liver evaluated >90 min after tail-vein injection. The graph depicts the mean normalized concentration of nanotubes in four mice ± SEM. Note the gradual increase of SWNT accumulation in liver after 30 min after injection.

Raster-scan image of mouse liver, using Raman spectroscopy in conjunction with SERS nanoparticles. (a) Whole-body map (1-mm steps) of nude mouse 2 h after tail-vein injection of SERS nanoparticles. Note how most of the SERS particles accumulated in the liver (L) (arrow), resulting in a well defined image. (b) Map of liver (750-μm steps), showing higher definition of liver (arrow) and slight distinction between the two liver lobes.

Accumulation of RGD SWNTs and plain nontargeted SWNTs within an integrin-positive U87MG tumor model at 24 h after i.v. injection. (a) Digital photograph of mouse depicting tumor area (black square) and corresponding Raman images acquired 24 h after SWNT injection by raster scan with 750-μm steps. Notice the accumulation of RGD SWNTs in the tumor area as opposed to the plain nontargeted SWNTs that show little to no accumulation in the tumor area. (b) Raman spectral analysis of RGD nanotubes and plain nontargeted nanotubes within the tumor at 24 h after SWNT injection. The graphed data show a significant increase (*, P < 0.05) in Raman signal in mice (n = 3 per group) injected with RGD nanotubes as opposed to mice injected with plain nanotubes, thus indicating accumulation of RGD SWNT to tumor site. This quantitative data supports the Raman images displayed in a.