Fluorescence correlation spectroscopy using quantum dots: advances, challenges and opportunities

Abstract

Semiconductor nanocrystals (quantum dots) have been increasingly employed in measuring the dynamic behavior of biomacromolecules using fluorescence correlation spectroscopy. This poses a challenge, because quantum dots display their own dynamic behavior in the form of intermittent photoluminescence, also known as blinking. In this review, the manifestation of blinking in correlation spectroscopy will be explored, preceded by an examination of quantum dot blinking in general.

Quantum Dots in Bioanalysis: A Review of Applications across Various Platforms for Fluorescence Spectroscopy and Imaging

“…It has been widely used to determine the hydrodynamic radii of QDs functionalized with different organic coatings or under different conditions, and it has been proposed as a method for accurately measuring QD concentrations and extinction coefficients. 275,277,278 In addition, Cramb's group has published several studies where QD-FCCS has been used to monitor ligand-receptor interactions. A pair of early studies investigated the streptavidin-biotin interaction in association with QDs (i.e., QD-streptavidin and QD-biotin conjugates).…”

Dynamics of quantum dots in angiogenic blood vessels: a fluorescence correlation spectroscopy study

“…It should be noted that when the additional "blink" term (Equation 2.5) was used to fit autocorrelation decays with the characteristic QD short-time anomalous shape, the value of the fitted diffusion coefficient was not significantly influenced 22 . This was verified by a comparison of diffusion coefficients fitting with the blink term and fitting without the blink term.…”

Measuring properties of nanoparticles in embryonic blood vessels: Towards a physicochemical basis for nanotoxicity

“…g blink (s) is a function that models the shape of the autocorrelation decay. Experimentally, g bink (s) was found to be best defined as [8]:…”

“…When a low excitation rates does not remove the anomalous shape, we used the following equation, which helps account for blinking [8]:…”

“…We have been employing fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) in the study of semi-conductor nanocrystals (aka quantum dots) to measure their solution dynamics and photophysics [8][9][10]. Recently, we have optimized an FCS set-up to measure the properties of fluorescent NPs in the blood stream of chicken embryos.…”