title: Blinking effect and the use of quantum dots in single molecule spectroscopy.
abstract: Luminescent semiconductor nanocrystals (quantum dots, QD) have unique photo-physical properties: high photostability, brightness and narrow size-tunable fluorescence spectra. Due to their unique properties, QD-based single molecule studies have become increasingly more popular during the last years. However QDs show a strong blinking effect (random and intermittent light emission), which may limit their use in single molecule fluorescence studies. QD blinking has been widely studied and some hypotheses have been done to explain this effect. Here we summarise what is known about the blinking effect in QDs, how this phenomenon may affect single molecule studies and, on the other hand, how the "on"/"off" states can be exploited in diverse experimental settings. In addition, we present results showing that site-directed binding of QD to cysteine residues of proteins reduces the blinking effect. This option opens a new possibility of using QDs to study protein-protein interactions and dynamics by single molecule fluorescence without modifying the chemical composition of the solution or the QD surface.
authors.affiliation: Albert-Ludwigs-Universität Freiburg, Institut für Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Rombach-Riegraf
authors.forename: Peter
authors.initials: P
authors.lastname: Oswald
authors.forename: Roland
authors.initials: R
authors.lastname: Bienert
authors.forename: Jan
authors.initials: J
authors.lastname: Petersen
authors.forename: M P
authors.initials: MP
authors.lastname: Domingo
authors.forename: Julian
authors.initials: J
authors.lastname: Pardo
authors.forename: P
authors.initials: P
authors.lastname: Gräber
authors.forename: E M
authors.initials: EM
authors.lastname: Galvez
mesh_terms: D000818:Animals; D002417:Cattle; D003545:Cysteine / Q000737:chemistry*; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D025941:Protein Interaction Mapping / Q000379:methods*; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D003545:Cysteine