A quinolinium-based dual-functional NIR fluorescent probe for the imaging of Aβ aggregation and mitochondrial pH.

Mitochondria are the most important energy supply centers in the cell, the changes in function and structure are implicated in many diseases. Among them, Aβ peptide, one of the targets of Alzheimer's disease, is closely related to mitochondrial autophagy, during the process of mitochondrial autophagy, the mitochondrial matrix will undergo acidification and the pH will be obviously reduced. Herein, a quinolinium-based NIR fluorescent probe QM12 was rationally designed and synthesized for the simultaneous imaging of Aβ aggregates and mitochondrial pH with different emission readout.

Near-Infrared Photooxygenation Theranostics Used for the Specific Mapping and Modulating of Amyloid-β Aggregation.

The photooxygenation of amyloid-β (Aβ) protein is considered a promising strategy against Alzheimer's disease (AD). The inhibition of Aβ aggregation or depolymerization of Aβ aggregates can effectively alleviate and improve the condition of AD. Herein, we report a series of "off-on" near-infrared quinolinium photosensitizers (QM20-QM22) based on D-π-A structures using a target-sensing catalyst activation (TaSCAc) strategy.

A novel near-infrared-emitting aza-boron-dipyrromethene-based remarkable fluorescent probe for Hg in living cells.

A new near-infrared (NIR)-emitting aza-boron-dipyrromethene dye with two electron-donating amino groups at 1- and 7-positions has been prepared via several steps of reactions. This probe showed a NIR absorption at 748 nm with an obvious shoulder peak at 634 nm in CHCN/HO. Interestingly, a NIR fluorescence emission at 843 nm was observed with a large Stokes shift of 95 nm.

Nile-Red-Based Fluorescence Probe for Selective Detection of Biothiols, Computational Study, and Application in Cell Imaging.

A new colorimetric and fluorescence probe based on Nile-red chromophore for the detection of biothiols has been developed, exhibiting high selectivity towards biothiols over other interfering species. shows a blue shift in absorption peak upon reacting with biothiols, from 587 nm to 567 nm, which induces an obvious color change from blue to pink and exhibits a 35-fold fluorescence enhancement at 645 nm in red emission range. displays rapid (<1 min) response for HS, which is faster than other biothiols (>5 min).

A novel fluorescent probe for the detection of AmpC beta-lactamase and the application in screening beta-lactamase inhibitors.

The rapid detection of β-lactamases (Blas) and effective screening of Bla inhibitors are critically important and urgent for solving antibiotic resistance and improving precision medicine. Here a novel fluorescent probe CDC-559 was designed and synthesized, which can be used for the selective and direct detection of AmpC Blas. More importantly, it can realize screening the Bla inhibitors with sulbactam sodium and tazobactam as model compounds, and the half-maximal inhibitory concentration are 0.

A near-infrared BODIPY-based fluorescent probe for ratiometric and discriminative detection of Hg and Cu ions in living cells.

A near-infrared distyryl boron dipyrromethene-based sensor bearing one bis(1,2,3-triazole)amino receptor has been synthesized. This probe selectively and quickly binds to Hg and Cu ions in CHCN/HO (5:1 v/v) and exhibits remarkably blue-shifted absorption and fluorescence bands due to the inhibition of the intramolecular charge transfer process. The fluorescence changes of this probe upon binding to Hg or Cu ion are totally different, undergoing a ratiometric fluorescence enhancement (for Hg) or a fluorescence quenching (for Cu) mechanism.

A lysosome-targeting dual-functional fluorescent probe for imaging intracellular viscosity and beta-amyloid.

A lysosome-targeting dual-functional fluorescent probe was rationally designed and developed for imaging intracellular lysosomal viscosity and beta-amyloid. More importantly, the real-time tracking of the dynamic movement of lysosomes, as vesicle structures, has been achieved using Lyso-MC.

Two novel rhodamine-based fluorescent probes for the rapid and sensitive detection of Fe: Experimental and DFT calculations.

Fe ions play an important role in both biological and environmental field. In this work, two novel rhodamine-based colorimetric and fluorescent probes (RBA2 and RBA3) were designed and synthesized for the efficient detection of Fe. Upon the addition of Fe, the fluorescence intensity of RBA2 and RBA3 enhanced 108-fold and 222-fold, respectively.

Correction: A colorimetric and far-red fluorescent probe for the highly sensitive detection of silver(i).

[This corrects the article DOI: 10.1039/C7RA11933J.].

Neutral merocyanine dyes: for in vivo NIR fluorescence imaging of amyloid-β plaques.

Two neutral merocyanine-based near-infrared fluorescent probes were for the first time developed through rational engineering of the classical cationic cyanine scaffold IR-780 for in vivo imaging of amyloid-β plaques. In vivo NIRF imaging revealed that the probe could penetrate the blood-brain barrier and efficiently differentiate the living transgenic and wild-type mice.

In vivo near-infrared fluorescence imaging of amyloid-β plaques with a dicyanoisophorone-based probe.

A dicyanoisophorone-based probe with two-photon absorption and NIR emission was developed for the in vivo fluorescence imaging of amyloid-β plaques, which exhibited high selectivity toward Aβ aggregates over other intracellular proteins. The detection limit was calculated to be as low as 109 nM. In vivo imaging studies indicated that the probe could penetrate the blood-brain barrier and label Aβ plaques in the living transgenic mice, and its specific binding to cerebral Aβ plaques was further confirmed by one- and two-photon ex vivo fluorescence imaging.

Design, Synthesis, and Evaluation of Isaindigotone Derivatives To Downregulate c-myc Transcription via Disrupting the Interaction of NM23-H2 with G-Quadruplex.

Transcriptional control of c-myc oncogene is an important strategy for antitumor drug design. G-quadruplexes in the promoter region have been proven to be the transcriptional down-regulator of this gene. The transcriptional factor NM23-H2 can reactivate c-myc transcription by unwinding the G-quadruplex structure.

A colorimetric and fluorescent dual probe for palladium in aqueous medium and live cell imaging.

A colorimetric and fluorescent dual probe for palladium species was rationally developed by combining the resorufin fluorophore with allyl chloroformate. The probe enables the visual detection of palladium based on its vivid color change from pale yellow to pink and its fluorescence off-on response to palladium in PBS solution. The detection limit was calculated to be as low as 2.

Colorimetric and fluorescence detection of G-quadruplex nucleic acids with a coumarin-benzothiazole probe.

A colorimetric and red-emitting fluorescent dual probe for G-quadruplexes was devised with a conjugated coumarin-benzothiazole scaffold. Its significant and distinct changes in both color and fluorescence enable the label-free and visual detection of G-quadruplex structures. In addition, this probe gives a distinct strong emission response to the nucleoli in fixed cells imaging, which might be attributed to the interaction between the probe and rDNA G-quadruplex based on the chromatin immunoprecipitation assay.

Synthesis and Evaluation of Quinazolone Derivatives as a New Class of c-KIT G-Quadruplex Binding Ligands.

The c-KIT G-quadruplex structures are a novel class of attractive targets for the treatment of gastrointestinal stromal tumor (GIST). Herein, a series of new quinazolone derivatives with the expansion of unfused aromatic ring system were designed and synthesized. Subsequent biophysical studies demonstrated that the derivatives with adaptive scaffold could effectively bind to and stabilize c-KIT G-quadruplexes with good selectivity against duplex DNA.

Development of a new colorimetric and red-emitting fluorescent dual probe for G-quadruplex nucleic acids.

A tailor-made colorimetric and red-emitting fluorescent dual probe for G-quadruplex nucleic acids was developed by incorporating a coumarin-hemicyanine fluorophore into an isaindigotone framework. The significant and distinct changes in both the color and fluorescence of this probe enable the label-free and visual detection of G-quadruplex structures.

Development of a universal colorimetric indicator for G-quadruplex structures by the fusion of thiazole orange and isaindigotone skeleton.

The rapid and convenient method for identification of all kinds of G-quadruplex is highly desirable. In the present study, a novel colorimetric indicator for a vast variety of G-quadruplex was designed and synthesized on the basis of thiazole orange and isaindigotone skeleton. Its distinct color change enables label-free visual detection of G-quadruplexes, which is due to the disassembly of dye H-aggregates to monomers.

Design, synthesis and evaluation of isaindigotone derivatives as dual inhibitors for acetylcholinesterase and amyloid beta aggregation.

A series of isaindigotone derivatives and analogues were designed, synthesized and evaluated as dual inhibitors of cholinesterases (ChEs) and self-induced β-amyloid (Aβ) aggregation. The synthetic compounds had IC(50) values at micro or nano molar range for cholinesterase inhibition, and some compounds exhibited strong inhibitory activity for AChE and high selectivity for AChE over BuChE, which were much better than the isaindigotone derivatives previously reported by our group. Most of these compounds showed higher self-induced Aβ aggregation inhibitory activity than a reference compound curcumin.