A newly synthesized visual bis(salamo)-based fluorescent chemosensor for exogenous detection of B4O72- in living cells and zebrafish.

A newly synthesized fluorescent chemosensor H6L was explored for detecting B4O72-, characterized by 1H NMR spectrum, mass spectrum and fluorescence spectra. During the detection process of B4O72-, the fluorescence is significantly enhanced and naked eye recognition can be performed under 365 nm UV light without any interference by other typical anions. The limit of detection is as low as 6.97 × 10-10 M. In addition, in order to broaden the application of salamo-based fluorescence sensors in the field of biology, except for the fluorescence imaging of HeLa cells, the first attempt of exogenous detection in zebrafish was conducted successfully.

Synthesis and characterization for a highly selective bis(salamo)-based chemical sensor and imaging in living cell.

A new sensor H5L for continuous identification of Cu2+, Al3+ and lysine was synthesized by Schiff base reactions. The sensor could specifically recognized Cu2+ in the EtOH/H2O (1:1 v/v) solution by UV-vis spectra, and the binding constant with Cu2+ can reach 1011 M-1, meanwhile, it was found by the naked-eye that the color of the solution was changed from colorless to yellow. The copper complex L-Cu2+ formed by the sensor H5L and Cu2+ could further recognize Al3+ and lysine in the fluorescence spectra. The LOD values of the three objects were 2.67 × 10-8, 1.96 × 10-8 and 5.59 × 10-9 M, respectively. In addition, fluorescence intracellular images of Al3+ and lysine were performed and obtained satisfactory results.

Synthesis of nitrogen-doped graphene quantum dots (N-GQDs) from marigold for detection of Fe3+ ion and bioimaging.

Graphene quantum dots (GQDs) are synthesized by the method of high-temperature pyrolysis from marigold granules and subsequently nitrogen-doped graphene quantum dots (N-GQDs) are synthesized from ethylenediamine by hydrothermal treatment, which shows a strong blue emission with 7.84% quantum yield (QY). This will be used in detection of Fe3+ in water environments and the field of bioimaging.

A novel biphenyl-derived salicylhydrazone Schiff base fluorescent probes for identification of Cu2+ and application in living cells.

A novel biphenyl-derived salicylhydrazone Schiff base (BSS) fluorescent probes for highly sensitive and selective identification of Cu2+ has been synthesized. In addition, the recognition has been proved experimentally. The results indicated that the complex forms a 1:1 complex with Cu2+ shows fluorescent quenching. Furthermore, the detection limit of 1.54×10-8M. More interesting, the probe BSS not only have a good biocompatibility in living cells, but also the sense behavior of Cu2+ in the cell nucleus.

Multistimuli-Responsive Luminescence of Naphthalazine Based on Aggregation-Induced Emission.

Stimuli-responsive luminescent materials, which are dependent on changes in physical molecular packing modes, have attracted more and more interest over the past ten years. In this study, 2,2-dihydroxy-1,1-naphthalazine was synthesized and shown to exhibit different fluorescence emission in solution and solid states with characteristic aggregation-induced emission (AIE) properties. A remarkable change in the fluorescence of 2,2-dihydroxy-1,1-naphthalazine occurred upon mechanical grinding, heating, or exposure to solvents. According to the characterization by solid-state fluorescence spectroscopy, X-ray crystallography, differential scanning calorimetry, and X-ray powder diffraction, the fluorescence change could be attributed to transitions between two structurally different polymorphs. These significant properties could also give 2,2-dihydroxy-1,1-naphthalazine more potential applications as a multifunctional material.

A coumarin-based two-photon probe for hydrogen peroxide.

A new fluorescence probe was developed for hydrogen peroxide (H2O2) detection based on donor-excited photo induced electron transfer (D-PET) mechanism, together with the benzil as a quenching and recognizing moiety. The benzil could convert to benzoic anhydride via a Baeyer-Villiger type reaction in the presence of H2O2, followed by hydrolysis of benzoicanhydride to give benzoic acid, and the fluorophore released. The probe was synthesized by a 6-step procedure starting from 4-(diethylamino)salicylaldehyde. A density functional theory (DFT) calculation was performed to demonstrate that the benzil was a fluorescence quencher. The probe was evaluated in both one-photon and two-photon mode, and it exhibited high selectivity toward H2O2 over other reactive oxygen species and high sensitivity with a detection limit of 0.09 µM. Furthermore, the probe was successfully applied to cell imaging of intracellular H2O2 levels with one-photon microscopy and two-photon microscopy. The superior properties of the probe made it of great potential use in more chemical and biological researches.

Turn-on phosphorescent chemodosimeter for Hg2+ based on a cyclometalated Ir(III) complex and its application in time-resolved luminescence assays and live cell imaging.

A novel "turn-on" phosphorescent chemodosimeter based on a cyclometalated Ir(III) complex has been designed and synthesized, which displays high selectivity and sensitivity toward Hg(2+) in aqueous media with a broad pH range of 4-10. Furthermore, by time-resolved photoluminescence techniques, some interferences from the short-lived background fluorescence can be eliminated effectively and the signal-to-noise ratio of the emission detection can be improved distinctly by using the chemodosimeter. Finally, the chemodosimeter can be used to monitor Hg(2+) effectively in living cells by confocal luminescence imaging.