Figure 8From: Cellular distribution and cytotoxicity of graphene quantum dots with different functional groupsRaman spectra of cells. (a) Mean Raman spectra of A549 cells before and after exposure to 200 μg/mL of GQDs. (b) Average Raman spectra of C6 cells before and after treated with GQDs at the concentration of 200 μg/mL. Excitation wavelength, 785 nm.Back to article page