Label-free high-resolution 3-D imaging of gold nanoparticles inside live cells using optical diffraction tomography

Abstract

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 suffers from phototoxicity and photobleaching. 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 with sub-micrometer 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. In addition, we perform quantitative imaging analysis including the segmentations of GNPs in the cytosol, the volume distributions of aggregated GNPs, and the temporal evolution of GNPs contents in HeLa and 4T1 cells.

Measurements of morphological and biophysical alterations in individual neuron cells associated with early neurotoxic effects in Parkinson's disease

“…1A), which is comparable to the setup used in previous work (40,55). The 3D RI distribution of the cell clearly shows cell boundaries and intracellular organelles such as nucleus and nucleoli, based on their distinct distributions of refractive index values (55)(56)(57). A SH-SY5Y cell was illuminated with a coherent laser beam.…”

Slight pH Fluctuations in the Gold Nanoparticle Synthesis Process Influence the Performance of the Citrate Reduction Method

“…Gold nanoparticles (AuNPs) have emerged as a promising platform for a growing number of biomedical and biotechnology applications in the fields of sensing [ 1 ], molecular diagnostic [ 2 ], therapeutic [ 3 ], and imaging [ 4 ], owing to their stability, biocompatibility, remarkable physicochemical properties, and easy surface functionalization with a wide range of ligands [ 5 , 6 ]. A prominent optic feature of AuNPs arises from the collective oscillation of the conduction electrons in the presence of an incident light, the so-called surface plasmon resonance (SPR) [ 7 ].…”

Neural Network for Optical Pathlength Demodulation in Wavelength Shifting Interferometry

“…OPL range shown is shortened to emphasize the differences between the networks. Note that σ DNN3 , trained on the most confined range, approaches the bound given in Eq (5)…”

“…(4), but surpassing it and beginning to approach the SPCRB in Eq. (5). No changes need to be made to the original optical system to take advantage of the improvement in sensitivity provided by the DNNs.…”