Noise-Free Dual-Wavelength Difference Imaging of Plasmonic Resonant Nanoparticles in Living Cells

Abstract

Herein, we demonstrated a new optical microscopy method to selectively image small-size gold nanoparticles (GNPs) inside noisy living cells through determination of the difference image between the probe beam (illuminated at the resonance wavelength of GNPs, 532 nm) and the reference beam (illuminated at 473 nm). From computer simulation and single-particle imaging experiments, we demonstrated that GNPs with a diameter of 45 nm could be selectively imaged in the GNPs/cell lysates mixture and inside living cells by dual-wavelength difference (DWD) imaging. The diffusion dynamics of nucleic acids functionalized GNPs on cell membranes and the internalization kinetics of these GNPs by living cells were explored with this method. Our real-time tracking experiments showed that statistically 80% of GNPs were under restricted diffusion on the cell membrane. The cell cytoskeleton fence effect, as observed in the single-particle tracking experiments, may be one of the main factors for the restricted diffusion mode.

Pericellular Matrix Enhances Retention and Cellular Uptake of Nanoparticles

“…23 Single AuNPs larger than 80 nm produce very strong plasmonic scattering emission under oblique illumination of white light and are readily distinguishable (yellow) from the intracellular scattering background (white) under a dark field microscope (DFM). 24 Additional assays indicate that these AuNPs are monodisperse, do not aggregate in the cell culture medium that contains serum, and have almost no cytotoxicity ( Figure S2, SI). Figure 1A and Figure 1B show the DFM images after incubating 120-nm AuNPs with thick-PCM cells and thin-PCM cells for 4 h, respectively.…”

Collective motion of bacteria and their dynamic assembly behavior

“…So far people have been using micron-sized passive particles to trace the hydrodynamics of the bacterial environment. During the past decade, our research group have developed a series of nano-imaging techniques capable of tracing single plasmonic nanoparticles with high sensitivity and high resolution [66][67][68][69][70][71]. Inspired by single particle tracing at the micron-scale, it is expected that a lot of new information on the collective motion of bacteria could be obtained by tracking the spatial and temporal variation of multiple single nanoparticle tracers at the nanoscale.…”

A single particle method for direct determination of molar concentrations of gold nanoparticles, and its application to the determination of the activity of caspase 3 and drug-induced cell apoptosis

“…Currently, certain noble metal nanoparticles as bio-labeling probes and biomaterials were widely used in bioassays [1], gene transferring [2,3], bio-imaging [4][5][6] and photothermal therapy [7,8] due to their unique optical and chemical properties. Compared to current fluorescent probes, noble metal nanoparticles such as GNP have special physical and chemical properties, such as no photo bleaching and blinking [9], no cytotoxicity [10], strong light absorption and scattering effect [11] etc.…”