Semiconductor nanocrystals for biological imaging

Fu, Aihua; Gu, Weiwei; Larabell, Carolyn A.; Alivisatos, A. Paul

doi:10.1016/j.conb.2005.08.004

Cited by 172 publications

(132 citation statements)

References 45 publications

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“…The parasubstituted methoxyisophthalic acids (6) were converted to the activated bis-thiazolide species (7). The bifunctionalized thiazolides were selectively coupled with methylamine under high-dilution conditions to give the mono-methylamides (8). These methylamides were then coupled to the 1,5-diaminopentane backbone to give the protected ligands (9).…”

Section: Resultsmentioning

confidence: 99%

Predicting Efficient Antenna Ligands for Tb(III) Emission

Samuel

Raymond

2008

Inorg. Chem.

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ABSTRACT:A series of highly luminescent Tb(III) complexes of para-substituted 2-hydroxyisophthalamide ligands (5LI-IAM-X) has been prepared (X = H, CH 3 , (C=O)NHCH 3 , SO 3 -, NO 2 , OCH 3 , F, Cl, Br) to probe the effect of substituting the isophthalamide ring on ligand and Tb(III) emission in order to establish a method for predicting the effects of chromophore modification on Tb(III) luminescence. The energies of the ligand singlet and triplet excited states are found to increase linearly with the -withdrawing ability of the substituent. The experimental results are supported by 2 time-dependent density functional theory (TD-DFT) calculations performed on model systems, which predict ligand singlet and triplet energies within ~5% of the experimental values. The quantum yield () values of the Tb(III) complex increases with the triplet energy of the ligand, which is in part due to the decreased non-radiative deactivation caused by thermal repopulation of the triplet. Together, the experimental and theoretical results serve as a predictive tool that can be used to guide the synthesis of ligands used to sensitize lanthanide luminescence.

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Section: Resultsmentioning

confidence: 99%

Predicting Efficient Antenna Ligands for Tb(III) Emission

Samuel

Raymond

2008

Inorg. Chem.

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“…When combined with ultrasensitive optical techniques, QDs allow tracking of individual biomolecules in live cells with high signal-to-noise ratio and over unprecedented durations (25)(26)(27). We examined retrograde transport of NGF-containing vesicles by using QD-NGF to mark these organelles.…”

Section: Qd-ngf Is Fully Biologically Activementioning

confidence: 99%

One at a time, live tracking of NGF axonal transport using quantum dots

Cui¹,

Chen

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

338

336

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Retrograde axonal transport of nerve growth factor (NGF) signals is critical for the survival, differentiation, and maintenance of peripheral sympathetic and sensory neurons and basal forebrain cholinergic neurons. However, the mechanisms by which the NGF signal is propagated from the axon terminal to the cell body are yet to be fully elucidated. To gain insight into the mechanisms, we used quantum dot-labeled NGF (QD-NGF) to track the movement of NGF in real time in compartmentalized culture of rat dorsal root ganglion (DRG) neurons. Our studies showed that active transport of NGF within the axons was characterized by rapid, unidirectional movements interrupted by frequent pauses. Almost all movements were retrograde, but short-distance anterograde movements were occasionally observed. Surprisingly, quantitative analysis at the single molecule level demonstrated that the majority of NGFcontaining endosomes contained only a single NGF dimer. Electron microscopic analysis of axonal vesicles carrying QD-NGF confirmed this finding. The majority of QD-NGF was found to localize in vesicles 50 -150 nm in diameter with a single lumen and no visible intralumenal membranous components. Our findings point to the possibility that a single NGF dimer is sufficient to sustain signaling during retrograde axonal transport to the cell body.live imaging ͉ nerve growth factor ͉ single molecule imaging ͉ NGF signaling ͉ retrograde transport N erve growth factor (NGF) is produced and released by target tissues to activate specific receptors at the axon terminals of innervating neurons. In order for NGF to regulate gene expression and the survival of target neurons, a signal must be moved a considerable distance, in some cases Ͼ1,000-fold the diameter of the neuron cell body. The elucidation of the mechanism(s) used to transmit NGF signal from the terminals of axons to cell bodies of neurons is yet to be fully defined. In that retrograde NGF signaling is critical for the survival and maintenance of neurons of both the peripheral and central nervous systems, and the underlying mechanisms are likely to be shared by related neurotrophic factors, the issue remains one of the most significant and intriguing questions in neurobiology (1-16).In the past, radio-labeled NGF ( 125 I-NGF) has been used to study the binding, internalization, and axonal transport of NGF. These studies facilitated the measurement of transport rate and provided insights into the endocytic pathways used for NGF transport (8,(16)(17)(18)(19). Fluorescent labels such as rhodamine (20), Texas red (21), and Cy3 (22) were also used to track NGF movement in neurons. However, because these previous methods have limited spatial and temporal resolution, they provide only a coarse look at what is expected to be a very dynamic process. Moreover, few studies have examined NGF-containing endosomes during axonal transit. Some have suggested that NGF is transported principally within early endosomes (4, 5, 7-14) whereas others suggest that NGF is transported in organelles with com...

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“…Accordingly, these nanoparticles have drawn much attention as promising fluorescent labels for biology, so that the interaction of proteins and nucleic acids with the CdS and ZnS quantum dots has been intensively studied (see [242][243][244][245][246][247][248] for reviews). It is noteworthy that the ZnS particles obtained from hydrothermal vent plumes could pass through 200 nm filters [249] and, hence, can be reasonably categorized as nanoparticles.…”

Section: Supporting Evidencementioning

confidence: 99%