Fluorescence Intensity and Lifetime Imaging of Gold Nanorods in Cells

Two-Photon luminescence (TPL) from gold nanorods shows considerable potential in biological imaging. Here we study the TPL properties of gold nanorods and their application in biological imaging. Through a spectroscopy study, TPL from gold nanorods is found to be strong and stable, and mainly governed by the longitudinal surface plasmon band. The application of gold nanorods as TPL imaging agents is demonstrated by studying the gold nanorods taken up by MDCK cells using both confocal imaging and fluorescence lifetime imaging microscopy (FLIM). TPL intensity from gold nanorods is found to be several times stronger than that from DAPI and the characteristic fluorescence lifetime of gold nanorods is found to be less than 100 ps, which can be used to distinguish gold nanorods from other fluorescent labels and endogenous fiuorophores in lifetime imaging.