3‐Dimensional Tracking of Non‐blinking ‘Giant’ Quantum Dots in Live Cells

Abstract

While semiconductor quantum dots (QDs) have been used successfully in numerous single particle tracking (SPT) studies due to their high photoluminescence efficiency, photostability, and broad palette of emission colors, conventional QDs exhibit fluorescence intermittency or ‘blinking,’ which causes ambiguity in particle trajectory analysis and limits tracking duration. Here, non-blinking ‘giant’ quantum dots (gQDs) are exploited to study IgE-FcεRI receptor dynamics in live cells using a confocal-based 3D SPT microscope. There is a 7-fold increase in the probability of observing IgE-FcεRI for longer than 1 min using the gQDs compared to commercially available QDs. A time-gated photon-pair correlation analysis is implemented to verify that selected SPT trajectories are definitively from individual gQDs and not aggregates. The increase in tracking duration for the gQDs allows the observation of multiple changes in diffusion rates of individual IgE-FcεRI receptors occurring on long (>1 min) time scales, which are quantified using a time-dependent diffusion coefficient and hidden Markov modeling. Non-blinking gQDs should become an important tool in future live cell 2D and 3D SPT studies, especially in cases where changes in cellular dynamics are occurring on the time scale of several minutes.

Plasmonic giant quantum dots: hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry

“…In summary, we have previously demonstrated the potential of photostable giant or thick-shell CdSe/CdS QDs for the range of applications from solid-state lighting to live-cell single-particle tracking. 11 – 13 Here, we show that such novel emitters are ideal components for hybrid semiconductor–metal nanocomposites for which the ensemble and single-dot gQD optical properties can be retained and new functionality realized. Namely, a photothermal heating effect and an ‘on-board’ temperature sensing capability located precisely at the point of heating (which could be further improved by including advanced dual-emitting nanoscale temperature sensors 49 ) are added.…”

Soft, Biological and Composite Nanomaterials

“…The increase in tracking duration for the gQDs allows the observation of multiple changes in diffusion rates of individual IgE-FcERI receptors occurring on long (>1 min) time scales, which we quantified using a time-dependent diffusion coefficient and hidden Markov modeling. [30] This work demonstrates the utility of using nonblinking gQDs as a tool for live cell 2D and 3D SPT studies, especially in cases in which changes in cellular dynamics occur on a time scale of several minutes. We note that following 3D molecular dynamics for long (minute) time periods in live cells requires both a photostable nonblinking probe (such as gQDs) and a means of tracking the motion in 3 dimensions, which is possible only by using two previous CINT-developed technologies, SPT and gQDs.…”

From Inside Out: How the Buried Interface, Shell Defects, and Surface Chemistry Conspire to Determine Optical Performance in Nonblinking Giant Quantum Dots

“…Thus, despite nominally similar structures—identical CdSe core and comparable “giant” CdS shell—gQD I and gQD II are unalike in terms of PL efficiency and PL stability. These are key performance criteria for a range of real‐world QD applications from single‐molecule tracking [ 35 , 36 , 37 ] to display technologies, [ 38 , 39 , 40 ] solid‐state lighting, [ 41 , 42 , 43 , 44 , 45 , 46 , 47 ] and single‐photon generation. [ 48 , 49 ] Notably, in the case of light‐emitting diode (LED) technologies, the thick shell has other benefits that are not affected by the choice of shell‐growth method.…”