Rice University scientists have developed a way of tracking single-walled carbon nanotubes under the skin that can pintpoint the location of cancer tumors. The nanotubes can be made to gather within tumors in higher concentrations than the rest of the body using attached antibodies, but spotting these nanostructures in vivo can be difficult.
Previously, it’s been possible to identify the location of the nanotubes under the skin, but not their depth. The researchers are now using a technique called spectral triangulation to be able to identify exactly where the nanotubes are bunching up.
When nanotubes are excited they emit short-wave infrared light of different frequencies. These scatter differently through tissue and comparing how different frequency light comes back to the detector helps to calculate the exact location of its source.
Some details from the study abstract in journal Nanoscale:
Structurally unsorted SWCNT [single-walled carbon nanotubes] samples emitting over a range of wavelengths are excited inside tissue phantoms by an LED matrix. The resulting SWIR [short-wave infrared] emission is sampled at points on the surface by a scanning fibre optic probe leading to an InGaAs spectrometer or a spectrally filtered InGaAs avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We therefore gauge the SWCNT–probe distance by analysing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence can be clearly detected through at least 20 mm of tissue phantom, and the 3D locations of embedded SWCNT test samples are found with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate two embedded SWCNT sources at distinct positions.
Study in journal Nanoscale: Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo…
Via: Rice University
