Lengthening the Lifetime of Common Emissive Probes to Microseconds by a Jigsaw‐Like Construction of NIR‐Responsive Nanohybrids

The exploration of advanced fluorescent probes that can detect divalent copper (Cu2+) in aqueous environments and even in live organisms is particularly valuable for understanding the occurrence and development of Cu2+-related diseases. In this work, we report the design and synthesis of an aggregation-induced emission luminogen (AIEgen)-based probe (TPE-Py-EEGTIGYG) by integrating an AIEgen, TPE-Py, with a peptide, EEGTIGYG, which can selectively detect Cu2+ in both aqueous solution and live cells. Peptide EEGTIGYG has dual functionality in the probe design, namely improving water solubility and providing specific cell membrane-binding ability. TPE-Py-EEGTIGYG can self-assemble into nanoaggregates at high concentration in aqueous solution (e.g., 25 μM), which possess large fluorescence output due to the restriction of intramolecular rotation of the phenyl rings on TPE-Py. The fluorescence of the TPE-Py-EEGTIGYG nanoaggregates can be significantly quenched by Cu2+ but not by other metal ions, achieving the selective detection of Cu2+ in aqueous media. Furthermore, TPE-Py-EEGTIGYG can exist as a molecular species and is very weakly fluorescent in dilute aqueous solution (e.g., 5 μM), but can however largely switch on its fluorescence upon specifically anchoring onto the cell membrane. The emissive probes on the cell membrane can be used for the detection of Cu2+ ions that move in and out of cells with a fluorescence “turn-off” mode.

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Comparison of Langmuir and emissive probes as diagnostics for turbulence studies in the low-temperature plasma of the torsatron TJ-K

Plasma Physics and Controlled Fusion ◽

10.1088/0741-3335/47/4/001 ◽

2005 ◽

Vol 47 (4) ◽

pp. 569-579 ◽

Cited By ~ 52

Author(s):

N Mahdizadeh ◽

F Greiner ◽

M Ramisch ◽

U Stroth ◽

W Guttenfelder ◽

...

Keyword(s):

Low Temperature ◽

Low Temperature Plasma ◽

Temperature Plasma ◽

Emissive Probes

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Current-Voltage and Floating-Potential characteristics of cylindrical emissive probes from a full-kinetic model based on the orbital motion theory

Journal of Physics Conference Series ◽

10.1088/1742-6596/958/1/012001 ◽

2018 ◽

Vol 958 ◽

pp. 012001 ◽

Cited By ~ 2

Author(s):

Xin Chen ◽

Gonzalo Sánchez-Arriaga

Keyword(s):

Kinetic Model ◽

Orbital Motion ◽

Floating Potential ◽

Model Based ◽

Current Voltage ◽

Emissive Probes

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Spectroscopically Well-Characterized RGD Optical Probe as a Prerequisite for Lifetime-Gated Tumor Imaging

Molecular Imaging ◽

10.2310/7290.2011.00018 ◽

2011 ◽

Vol 10 (6) ◽

pp. 7290.2011.00018 ◽

Cited By ~ 15

Author(s):

Julia Eva Mathejczyk ◽

Jutta Pauli ◽

Christian Dullin ◽

Joanna Napp ◽

Lutz-F. Tietze ◽

...

Keyword(s):

Fluorescence Lifetime ◽

Nude Mice ◽

Near Infrared ◽

Tumor Imaging ◽

Specific Binding ◽

Optical Probe ◽

Detection Sensitivity ◽

Rgd Peptides ◽

Emissive Probes

Labeling of RGD peptides with near-infrared fluorophores yields optical probes for noninvasive imaging of tumors overexpressing αvβ3 integrins. An important prerequisite for optimum detection sensitivity in vivo is strongly absorbing and highly emissive probes with a known fluorescence lifetime. The RGD-Cy5.5 optical probe was derived by coupling Cy5.5 to a cyclic arginine–glycine–aspartic acid–d-phenylalanine–lysine (RGDfK) peptide via an aminohexanoic acid spacer. Spectroscopic properties of the probe were studied in different matrices in comparison to Cy5.5. For in vivo imaging, human glioblastoma cells were subcutaneously implanted into nude mice, and in vivo fluorescence intensity and lifetime were measured. The fluorescence quantum yield and lifetime of Cy5.5 were found to be barely affected on RGD conjugation but dramatically changed in the presence of proteins. By time domain fluorescence imaging, we demonstrated specific binding of RGD-Cy5.5 to glioblastoma xenografts in nude mice. Discrimination of unspecific fluorescence by lifetime-gated analysis further enhanced the detection sensitivity of RGD-Cy5.5-derived signals. We characterized RGD-Cy5.5 as a strongly emissive and stable probe adequate for selective targeting of αvβ3 integrins. The specificity and thus the overall detection sensitivity in vivo were optimized with lifetime gating, based on the previous determination of the probes fluorescence lifetime under application-relevant conditions.

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