Ying Yue

A Bodipy-based derivative for selective fluorescence sensing of homocysteine and cysteine

A method for the selective fluorescence sensing of homocysteine (Hcy) and cysteine (Cys) under neutral pH conditions, based on the reaction of the simple aldehyde containing Bodipy dye with Hcy/Cys, has been developed. The location of the aldehyde group at the Bodipy core is important and has an effect on the cyclization with Hcy/Cys.

Selective electrochemical determination of trace level copper using a salicylaldehyde azine/MWCNTs/Nafion modified pyrolytic graphite electrode by the anodic stripping voltammetric method

A novel Cu2+ electrochemical sensor based on a salicylaldehyde azine/MWCNTs/Nafion-modified pyrolytic graphite electrode was prepared for anodic stripping analysis of Cu2+. Salicylaldehyde azine was synthesized and then used for the selective determination of the heavy metal pollutant Cu2+ due to its azine structure, which gave selective complexing ability toward Cu2+. The use of MWCNTs with their strong adsorption ability could greatly enhance the sensitivity. Nafion, a proton-exchange polymer, was used as the conductive matrix in which the salicylaldehyde azine and MWCNTs could be strongly fixed to the substrate electrode surface. The as-prepared electrochemical sensor showed remarkably enhanced selectivity and sensitivity towards Cu2+. The response current of the sensor was linear with Cu2+ concentration ranging from 5 to 300 nM under 15 min accumulation at open-circuit potential, with a very low detection limitation of about 1 nM. The hybrid functionalized electrode also exhibited good selectivity to avoid the interference of other heavy metal ions like Cd2+, Pb2+ and Hg2+ in the mixture solution together with Cu2+. Real application towards environmental sample analysis confirmed that the modified electrode could be applied for the selective determination of trace levels of Cu2+ in the Yellow River.

Recognition and sensing of AcO− and F− using a calix[4]pyrrole-derived hydrazone: a potential molecular keypad lock

Calix[4]pyrrole based anion receptors 1 and 2 have been synthesized. The recognition and sensing process has been studied by UV-vis absorption and partial 1H NMR titration experiments. Receptor 1 could act as a colorimetric sensor for fluoride anions, and receptor 2 could recognize F− and AcO− anions in DMSO solvent. Moreover, this type of sensing behaviour could successfully mimic a molecular level keypad lock stimulated by the two sequential chemical inputs (AcO− and F−), which has the potential for application in security devices.

A BODIPY based indicator for fluorogenic detection of salicylaldehyde with off–on emission

A turn-on fluorescent indicator 1 based on a BODIPY derivative for the detection of salicylaldehyde in aqueous solution by fluorescence spectroscopy has been developed. The formation of a Schiff base between probe 1 and salicylaldehyde suppressed the PET process and prohibited the CN isomerization accounting for the fluorescence response of probe 1. Two major reaction products of probe 1 with salicylaldehyde were obtained and characterized by 1H NMR and HRMS spectroscopy. Weakly fluorescent polymeric films have been obtained by embedding the indicator in PMMA, which can be used for the fluorescence detection of salicylaldehyde in polymer matrices.

Spectroscopic analysis on structure-affinity relationship in the interactions of different oleanane-type triterpenoids with bovine serum albumin

Oleanane-type triterpenoids serve as an important group of plant secondary metabolites with a variety of biological activities and the C-3 position substitution pattern is a significant structural feature for their biological activities. Three selected oleanane-type triterpenoids (glycyrrhizin, glycyrrhetinic acid, and carbenoxolone) bearing different substituents (glucuronic acid dimer, hydroxyl, and succinyl groups) at the C-3 position were studied for their affinities to bind bovine serum albumin (BSA) by steady-state fluorescence, synchronous, three-dimensional fluorescence and ultraviolet-visible (UV-vis) absorption spectra. The binding mechanism of the triterpenoids to BSA is due to the formation of the triterpenoids-BSA complex and the binding affinity is strongest for carbenoxolone and ranked in the order carbenoxolone > glycyrrhetinic acid > glycyrrhizin. The thermodynamic parameters calculated at different temperatures showed that triterpenoids binding to BSA primarily depended on hydrophobic interaction and hydrogen bonding. The distance between the bound triterpenoid and BSA was determined on the basis of the Försters energy transfer theory. Displacement experiments using phenylbutazone and ibuprofen showed the binding site of triterpenoids on BSA at subdomain IIA (Sudlows site I). The effect of triterpenoids on BSA conformation was analyzed by UV-vis absorption, and synchronous and three-dimensional fluorescence spectra. These results revealed that the C-3 position substitution pattern significantly affects the structure-affinity relationships of oleanane-type triterpenoid binding to BSA and further affects the bioavailability of triterpenoids in the blood circulatory system.

Construction of a selective electrochemical sensing solid–liquid interface for the selective detection of fluoride ion in water with bis(indolyl)methane-functionalized multi-walled carbon nanotubes

Based on the fluoride ion recognition ability of nitro-substituted 3,3′-bis(indolyl)methane (Nbim) and unique properties of multi-walled carbon nanotubes (MWCNTs) with enlarged active surface area and high electrical conductivity, a new solid–liquid interface for the selective detection of fluoride ion in water was fabricated by a Nbim/MWCNT-modified glassy carbon electrode. To transform the molecular interactions occurring at the solid liquid interface into measurable signals, electrochemical techniques were used through the electron transfer mediator of K3Fe(CN)6. Because of the synergistic effect of Nbim and MWCNTs, the as-prepared electrochemical sensing interface can be applied for the selective voltammetric determination of non-electroactive analytes (F−) based on the changes in the peak currents of the ferricyanide/ferrocyanide couple. The response current was linear, with F− concentration in the range from 1 μM to 130 μM and a detection limitation of 0.1 μM. This study offers a new strategy for the detection F− by a solid interface in practical water samples.