Previously we have demonstrated surface plasmon enhanced energy transfer between fluorophors and gold nanorods under two-photon excitation using fluorescence lifetime imaging microscopy (FLIM) in both solution and intracellular phases. These studies demonstrated that gold nanoparticle-dye energy transfer combinations are appealing, not only in FRET imaging, but also energy transfer-based fluorescence lifetime sensing of bio-analytes. Here, we apply this approach to study the internalization of gold nanorods (GNRs) in HeLa cells using early endosome labeling maker GFP. Observed energy transfer between GFP and GNRs indicates the involvement of endocytosis in GNR uptake. Moreover, a novel nanoprobe based on oligonucleotide functionalized gold nanorod for nucleic acid sensing via dye-GNRs energy transfer is demonstrated, potentially opening up new possibilities in cancer diagnosis and prognosis. The influence of oligonucleotide design on such nanoprobe performance was studied for the first time using time-resolved fluorescence spectroscopy, bringing new insight to the optimization of the nanoprobe.
- gold nanorods
- energy transfer
- fluorescence lifetime imaging microscopy