…A new imaging tool was demonstrated for tracking structures in living cells and the bloodstream that will provide information for the use of nanotubes for biomedical and clinical applications.The conventional imaging method uses luminescence, which is limited because it detects the semiconducting nanotubes but not the metallic ones.
The new imaging technique, called transient absorption, uses a pulsing near-infrared laser to deposit energy into the nanotubes, which then are probed by a second near-infrared laser.
The researchers have overcome key obstacles in using the imaging technology, detecting and monitoring the nanotubes in live cells and laboratory mice, as it is done at high speed, it can be seen what’s happening in real time as the nanotubes are circulating in the bloodstream.
One challenge in using the transient absorption imaging system for living cells was to eliminate the interference caused by the background glow of red blood cells, which is brighter than the nanotubes.
The researchers solved this problem by separating the signals from red blood cells and nanotubes in two separate “channels.” Light from the red blood cells is slightly delayed compared to light emitted by the nanotubes. The two types of signals are “phase separated” by restricting them to different channels based on this delay.
Label-free imaging tool tracks nanotubes in cells, Materials Today, http://www.materialstoday.com/view/22516/
Purdue University, http://www.purdue.edu/newsroom/research/2011/