Two-photon luminescence and energy transfer of gold nanorods for cell imaging

We have demonstrated energy transfer between 4´-6-Diamidino-2-phenylindole (DAPI), a commonly used DNA label, and gold nanoparticles under two-photon excitation in both solution and cell culture. Interestingly, gold nanorods are shown to provide more efficient energy transfer than gold nanospheres, due to the overlapping of longitudinal surface plasmon mode with the incidence excitation wavelength. The energy transfer process has been employed in the study of nanorods intracellular trafficking using gold nanorod-GFP pairs. The study shows the possibility of exploiting both the two-photon luminescence (TPL) imaging and energy transfer process in intra-cellular imaging and sensing.