RT Journal Article SR Electronic T1 Label-free high-resolution 3-D imaging of gold nanoparticles inside live cells using optical diffraction tomography JF bioRxiv FD Cold Spring Harbor Laboratory SP 097113 DO 10.1101/097113 A1 Doyeon Kim A1 Nuri Oh A1 Kyoohyun Kim A1 SangYun Lee A1 Jiho Park A1 YongKeun Park YR 2016 UL http://biorxiv.org/content/early/2016/12/28/097113.abstract AB Delivery of gold nanoparticles (GNPs) into live cells has high potentials, ranging from molecular-specific imaging, photodiagnostics, to photothermal therapy. However, studying the long-term dynamics of cells with GNPs using conventional fluorescence techniques suffer from phototoxicity and photobeaching. Here, we present a method for 3-D imaging of GNPs inside live cells exploiting refractive index (RI) as imaging contrast. Employing optical diffraction tomography, 3-D RI tomograms of live cells with GNPs are precisely measured for an extended period of time with sub-micrometre resolution. The locations and contents of GNPs in live cells are precisely addressed and quantified due to their distinctly high RI values, which was validated by confocal fluorescence imaging of fluorescent dye conjugated GNPs. We present segmentations of GNPs from cytosols and perform quantitative analysis of the volume distribution of aggregated GNPs as well as the temporal evolution of GNPs contents in HeLa and 4T1 cells.