Application of Raman Spectroscopy for Analysis of Carbon Nanotube Distribution in Living Cells

We have used Raman spectroscopy combined with confocal microscopy to study suspensions of single-wall and double-wall carbon nanotubes of different lengths and also multiwall carbon nanotubes. We have shown that the intensity of the G mode in the Raman spectrum of carbon nanotubes is directly proportional to the nanotube concentration, the exposure time, the exciting radiation power, and depth of focus in the transparent sample under study. We have established that the Raman spectra of longer carbon nanotubes (~1 μm) are characterized by higher intensity of the G mode compared with short carbon nanotubes (~250–450 nm). The dependences obtained were used to determine the local intracellular concentration of carbon nanotubes within the waist of the exciting laser beam, with the aim of mapping the carbon nanotube distribution inside the cells.