Figure 4.

Label-free detection of non-carboxylated C2-SWNTs and carboxylated C3-SWNTs inside NRK cells by confocal Raman microscopy. NRK cells grown on glass cover slips were incubated in media with C2- or C3-SWNT dispersions at a concentration of 100 μg/mL for 48 h with the addition of 0.12 M sucrose during the last 24 h. The cells were washed, fixed with paraformaldehyde, air-dried, and examined by confocal Raman microscopy with a 532 nm laser. (A) Optical image of a NRK cell incubated with C2-SWNT dispersion. (B) Optical image from (A) was overlaid with a Raman scan of the same area where the SWNT G-band signal (1460 – 1700 cm⁻¹) at every pixel was mapped using a thermal color scale with yellow being the highest intensity. (C) Background-corrected Raman spectrum taken from one pixel in the hot spot indicated by the arrow in (B). The inset shows the enlarged RBM region of the spectrum. (D) Optical image of a cell incubated with C3-SWNT dispersion was overlaid with a Raman scan of the same area to show co-localization of the SWNT Raman signals with the vesicles.