Observing photophysical properties of quantum dots in air at the single molecule level: advantages in microarray applications.
ABSTRACT Quantum dots (QDs) are promising fluorescent tags for microarrays. Because most microarrays are analyzed under dry conditions, it is necessary to examine the photo properties of QDs in air. We demonstrate that the photophysical characteristics of individual quantum dots are different at the liquid/solid interface compared with QDs at the air/solid interface by observing them through a wide-field fluorescence microscope. QDs in air show higher photo-stability, higher fluorescence signal, slower spectral blue shift rate, less blinking and shorter bulk fluorescence lifetime than those in solution. These beneficial properties indicate QDs are good alternative fluorescent probes for microarrays.
Article: Simple Förster resonance energy transfer evidence for the ultrahigh quantum dot quenching efficiency by graphene oxide compared to other carbon structures[show abstract] [hide abstract]
ABSTRACT: Förster resonance energy transfer (FRET) entails the transfer of energy from a photoexcited energy donor to a close energy acceptor. In this regard, quantum dots (QDs), as donors, are quenched when they are next to an acceptor material. Graphite, carbon nanotubes (CNTs), carbon nanofibers (CNFs) and graphene oxide (GO) were explored as energy acceptors of QD FRET donors in the solid phase. In our setup, the higher estimated values of quenching efficiency for each material are as follows: graphite, 66 ± 17%; CNTs, 71 ± 1%; CNFs, 74 ± 07% and GO, 97 ± 1%. Among these materials, GO is the best acceptor of QD FRET donors in the solid phase. Such an ultrahigh quenching efficiency by GO and the proposed simple mechanism may open the way to several interesting applications in the field of biosensing.Carbon 07/2012; 50(8):2987–2993. · 5.38 Impact Factor