The unique optoelectronic properties of semiconductor nanocrystals (quantum dots, QDs), have led to many advances in optoelectronic devices, bioimaging, and biosensing. Recent studies have shown that atomically defined, zero-dimensional magic-size clusters (MSCs) play a crucial role during the nucleation and growth of QDs. A major challenge is the preparation of the MSCs in single-ensemble form without coexistence of other-size QDs. Here we present a heat-up one-pot synthesis approach for the preparation of single-sized ZnSe MSCs. By using the thiol ligand 1-dodecanethiol, we could obtain new insights into the complex interplay of precursors and ligands during MSCs formation.
We present a method of high resolution, non-invasive, in vivo vascular imaging obtained using watersoluble and bright SWIR-emitting gold nanoclusters presenting an anisotropic surface charge combined with SWIR detection and Monte Carlo processing of the images. We applied this approach to quantify vessel complexity in mice presenting vascular disorders.
Semiconductor nanocrystals (quantum dots - QDs) possess unique photophysical properties that make them highly interesting
for many biochemical applications. Besides their common use as fluorophores in conventional spectroscopy and
microscopy, QDs are well-suited for studying Förster resonance energy transfer (FRET). Size-dependent broadband
absorption and narrow emission bands offer several advantages for the use of QDs both as FRET donors and acceptors.
QD-based FRET pairs can be efficiently used as biological and chemical sensors for highly sensitive multiplexed detection.
In this contribution we present the use of several commercially available QDs (Qdot® Nanocrystals - Invitrogen) as
FRET donors in combination with commercial organic dyes as FRET acceptors. In order to investigate the FRET process
within our donor-acceptor pairs, we used biotinylated QDs and streptavidin-labeled dyes. The well-known biotinstreptavidin
molecular recognition enables effective FRET from QDs to dye molecules and provides defined distances
between donor and acceptor. Steady-state and time-resolved fluorescence measurements were performed in order to
investigate QD-to-dye FRET. Despite a thick polymer shell around the QDs, our results demonstrate the potential of
these QDs as efficient donors both for steady-state and time-resolved FRET applications in nano-biotechnology.