Fig. 2.

Video-rate imaging of SWNTs in a live mouse. Frames from video imaging of mice injected with SWNTs. At (A and E) 3.5 s following tail-vein injection, the lungs are the dominant feature, corresponding to flow of the oxygen-poor, SWNT-rich blood to the lungs. (B and F) At 5.2 s, the SWNT-rich blood flows through the highly vascularized kidney. (C and G) The liver becomes apparent at 17.3 s p.i., whereas the (D and H) spleen becomes visible at 69 s p.i.. Scale bars in all images represent 1 cm. (I and J) Normalized ROI time courses over the organs in the raw images. For clarity, frames where the mouse is breathing were not included. The lungs, kidney, and liver show large spikes shortly after injection (approximately 5 s) followed by a return to a steady-state intensity within 20 s. The purple line in I shows the predicted time for blood to make one pass through the body, leading to a steady-state SWNT signal in the body. The spleen shows a deviation from this behavior, showing no early spike and a monotonic increase in signal with increasing time.