Search results for "fluorescent probes"
showing 10 items of 11 documents
Highly Selective Detection of Nerve‐Agent Simulants with BODIPY Dyes
2014
Two chromo-fluorogenic probes, each based on the boron dipyrromethene core, have been developed for the detection of nerve-agent mimics. These chemosensors display both a color change and a significant enhancement of fluorescence in the presence of diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP). No interference from other organophosphorus compounds or acids has been observed. Two portable chemosensor kits have been developed and tested to demonstrate its practical application in real-time monitoring.
Development of functionalized SYBR green II related cyanine dyes for viral RNA detection
2020
Fluorescent probes for sensing nucleic acids have found widespread use in the field of cell and molecular biology. However, probes combined with potential for post-synthetic conjugation, e.g. for intra-endosomal measurements of RNA, are unavailable. Herein we developed cyanine dyes that can be conjugated to viral capsid or other targets. First, we solved the crystal structure of SYBR Green II. The structural elucidation of this commonly used RNA probe provided the basis for synthesizing similar molecules with much desired function for post-synthetic conjugation. To address this need, cyanine dyes were prepared using an alternative synthesis protocol. All studied compounds showed considerabl…
Supramolecular Association of Halochromic Switches and Halloysite Nanotubes in Fluorescent Nanoprobes for Tumor Detection
2022
Fluorescence imaging has become an indispensable tool in the biomedical laboratory to elucidate the fundamental dynamic and structural factors regulating cellular processes. The development of fluorescent nanoprobes represents a challenge to detect any cellular process under a microscope. Herein, a fluorescent nanomaterial was synthesized by exploiting the supramolecular interaction between a halochromic switch (1Cl) and halloysite nanotubes (HNTs). The successful synthesis of a HNTs/1Cl nanomaterial was confirmed by thermogravimetric analysis and Fourier transform infrared. The aqueous mobility was investigated by dynamic light scattering and ζ-potential measurements as well. Furthermore, …
Highly selective fluorescence detection of hydrogen sulfide by using an anthracene-functionalized cyclam-CuII complex
2013
An anthracene-functionalised cyclam-copper(II) complex for the detection of HS- in aqueous environments has been prepared. This probe displays poor fluorescence but can selectively and sensitively detect HS- anions in water over other anions, biothiols and common oxidants such as H2O2 through remarkably enhanced emission. This turn-on response in the presence of the HS- anion is ascribed to a demetallation reaction that inhibits emission quenching observed in the initial complex as a result of the presence of the paramagnetic Cu2+ centre. Moreover, real-time fluorescence imaging measurements confirm that probe [Cu(1)](2+) can be easily used to detect intracellular HS- at micromolar concentr…
Probing the internal environment of PVP networks generated by irradiation with different sources
2010
Poly(N-vinyl-2-pyrrolidone) (PVP) hydrogels have been synthesised from the aqueous solutions of the same linear polymer by two different radiation sources: electron beams and UV rays. The present investigation couples conventional hydrogel characterisation techniques with the study of the partition equilibria, fluorescence behaviour and release of two different molecular probes, 1-anilino-8-naphthalene sulphonate (ANS) and Thioflavin T (ThT). The two probes have comparable molecular weight and different structural and optical properties. The chemical networks produced upon irradiation in different experimental conditions presented quite distinctive mechanical spectra, yielded to different…
A micellar multitasking device: sensing pH windows and gauging the lipophilicity of drugs with fluorescent signals.
2010
A multitasking fluorescent device can be obtained by forming micelles of Triton X-100, containing a lipophilic macrocyclic Cu(2+) complex and the coordinating fluorophore Coumarin 343 (C343), which features a COOH moiety. At low pH the two micellised components do not interact, and the fluorescence of Courmarin 343 (C343) is intense. At intermediate pH, C343 is deprotonated and coordinates to the Cu(2+) centre in its apical position, with fluorescence quenching. At higher pH the deprotonated C343 is displaced from Cu(2+) by the formation of an OH(-) complex, and the fluorescence is revived. This allows the system to carry out its first task as it behaves as an "on-off-on" fluorescent sensor…
Fluorescent metal-based complexes as cancer probes.
2020
Abstract The ability to track drugs inside of cells and tumours has been highly valuable in cancer research and diagnosis. Metal complexes add attractive features to fluorescent drugs, such as targeting and specificity, solubility and uptake or photophysical properties. This review focuses on the latest fluorescent metal-based complexes, their cellular targets, photophysical properties and possible anticancer effects.
Coumarin-Phosphine-Based Smart Probes for Tracking Biologically Relevant Metal Complexes: From Theoretical to Biological Investigations
2016
International audience; Ten metal-based complexes and associated ligands have been synthesized and characterized. One of the metal ligands is a coumarin-phosphine derivative, which displays tunable fluorescence properties. The fluorescence is quenched in the case of the free ligand and ruthenium and osmium complexes, whereas it is strong for the gold complexes and phosphonium derivatives. These trends were rationalized by theoretical calculations, which revealed non-radiative channels involving a dark state for the free ligands that is lower in energy than the emissive state and is responsible for the quenching of fluorescence. For the Ru-II and Os-II complexes, other non-radiative channels…
Aza-macrocyclic triphenylamine ligands for G-quadruplex recognition
2018
A new series of triphenylamine-based ligands with one (TPA1PY), two (TPA2PY) or three pendant aza-macrocycle(s) (TPA3PY) has been synthesised and studied by means of pH-metric titrations, UV/Vis spectroscopy and fluorescence experiments. The affinity of these ligands for G-quadruplex (G4) DNA and the selectivity they show for G4s over duplex DNA were investigated by Forster resonance energy transfer (FRET) melting assays, fluorimetric titrations and circular dichroism spectroscopy. Interestingly, the interactions of the bi- and especially the tri-branched ligands with G4s lead to a very intense redshifted fluorescence emission band that may be associated with intermolecular aggregation betw…
Visualising G-quadruplex DNA dynamics in live cells by fluorescence lifetime imaging microscopy
2020
Guanine rich regions of oligonucleotides fold into quadruple-stranded structures called G-quadruplexes (G4s). Increasing evidence suggests that these G4 structures form in vivo and play a crucial role in cellular processes. However, their direct observation in live cells remains a challenge. Here we demonstrate that a fluorescent probe (DAOTA-M2) in conjunction with fluorescence lifetime imaging microscopy (FLIM) can identify G4s within nuclei of live and fixed cells. We present a FLIM-based cellular assay to study the interaction of non-fluorescent small molecules with G4s and apply it to a wide range of drug candidates. We also demonstrate that DAOTA-M2 can be used to study G4 stability i…