Development of peroxynitrite-responsive fluorescence probe for recognition of drug-induced liver injury

Peroxynitrite (ONOO^-) as an active substance, is produced during normal physiological process, which plays an important role in maintaining cell REDOX balance and cell function. Moreover, the peroxynitrite is involved in many diseases and especially can be used as a biomarker of drug-induced liver injury (DILI). Therefore, in this work, we synthesized a fluorescent probe JQ-3 for detecting ONOO^-. The results showed the probe JQ-3 possessed excellent selectivity, fast response time (10 min) and low detection limit (32 nM). The probe JQ-3 is almost unaffected by pH, showing the potential application in biological systems. Moreover, the probe JQ-3 can be successfully used for the detection of exogenous and endogenous ONOO^- in living cells and zebrafish. At the same time, the DILI was successfully recognized by visualizing ONOO^- with JQ-3 in living cells and zebrafish. Therefore, the probe JQ-3 provides a potential tool for detecting ONOO^- to understand physiological and pathology processes of disease.

Hydrogen bond regulated hydrogen sulfate ion recognition: an overview

Hydrogen sulfate possesses substantial biological importance, having a colossal impact on physiological and environmental events. Therefore, several scientific groups have devoted serious effort to the development of versatile colorimetric and fluorimetric HSO4- sensors. Along with the scope, challenges, and significance, this review emphasizes the advancement of the optical recognition of HSO4- based on hydrogen bonding during the past two decades. Moreover, hydrogen-bond-driven proton transfer, ESIPT, ICT, PET, CHEF, and TBET mechanisms that allow for the optical detection of HSO4- are also discussed concisely. The foundation of this review includes the key points of the sensing process, like the nature of spectroscopic changes, selectivity and sensitivity, naked-eye color changes, the reusability of sensors, and the in vivo detection of HSO4-, if any. Special attention is focused on the correlation between the photophysical changes and the underlying interaction mechanisms that triggered the recognition aspect.

Estimation of bisulfate in edible plant foods, dog urine, and drugs: picomolar level detection and bio-imaging in living organisms

In order to explore the properties of any species in solution, the actual, i.e. equilibrium concentration of the free species should be taken into account. Researchers have not paid attention to the deprotonation equilibrium between HSO4- and SO42- while probing bisulfate ion. In this study, we have addressed this concern and developed two zwitterions, CG (coumarin-integrated glycine) and CA (coumarin-integrated alanine), for the selective detection of HSO4- at a picomolar level (50 to 325 pM) with very high binding affinity (∼108 M-1) in pure water at physiological pH. The principle of HSO4- recognition was established via UV-vis and fluorescence techniques. DFT calculations suggested that the H-bonding interactions between the probes and HSO4- are the driving force for this unforeseen selectivity. The membrane penetration ability and nontoxicity of CG/CA enable them to function as staining agents in living brine shrimps and bacteria. The use of these probes for the estimation of HSO4- in various day-to-day edible foods and drugs along with urine samples is unprecedented. The significance and novelty of this study lies in the application and development of assays for estimating bisulfate in several real-world samples that are predominantly aqueous in nature, which are the first of their kind.

A simple benzimidazole styryl-based colorimetric chemosensor for dual sensing application

A new colorimetric styryl-benzimidazole based receptor to recognize more than one analyte trans-2-[4'-(dimethylamino)styryl]benzimidazole) (L1) has been synthesized and fully characterized by ¹³C and ¹H NMR, elemental analysis, UV-vis spectroscopy, and HRMS. Investigation of sensing ability of receptor L1 was carried out in presence of multiple anions (Br^-, CN^-, Cl^-, ClO₄^-, F^-, HSO₄^-, PF₆^-, NO₃^-, S^2-, OH^-, AcO^- and H₂PO₄^-) and cations (Cu²⁺, Cr³⁺, Al³⁺, Mg²⁺, Cd²⁺, Ni²⁺, Fe³⁺, K⁺, Fe²⁺, Mn²⁺, Ag⁺, Hg²⁺, Ca²⁺, Co²⁺, Pb²⁺, Na⁺, and Zn²⁺) by using UV-vis spectroscopy. Receptor L1 showed colorimetric response towards only for HSO₄^- ion. Receptor L1-HSO₄^- interaction confirmed with the help of ¹H NMR titration. Among various cations, L1 selectively sense the Cu²⁺ and Al³⁺ with the drastic colour change from yellow to green and dark yellow respectively. The stoichiometric binding ratio of L1 with HSO₄^-, Cu²⁺, and Al³⁺ found to be 1:1 by jobs method and HRMS data proved the complex formation between L1 and Cu²⁺/Al³⁺ with very low detection limit. In addition to explore practical applicability of L1, paper strips have been made and used to detect HSO₄^- and Cu²⁺ ions, respectively, up to 10 ppm level.

The construction of an effective far-red fluorescent and colorimetric platform containing a merocyanine core for the specific and visual detection of thiophenol in both aqueous medium and living cells

Thiophenol is toxic to the environment and biological systems although it is an indispensable material for chemical products.

Columnar self-assembly of luminescent bent-shaped hexacatenars with a central pyridine core connected with substituted 1,3,4-oxadiazole and thiadiazoles

Multifunctional pyridine based bent shaped polycatenars stabilizing liquid crystalline and organogel self-assembly.

Novel π-extended hybrid xanthene dyes with two spirolactone rings for optoelectronic and biological applications

Two hybrid xanthene dyes that can operate as half-subtractors in methanol and can target mitochondria have been developed.

Exploring organic photosensitizers based on hemicyanine derivatives: a sustainable approach for preparation of amide linkages

Hemicyanine derivatives C1–C4 have been synthesized and show strong absorption in the visible region, good water solubility, efficient intersystem crossing, a high singlet oxygen quantum yield and high ability to transport electrons from the donor to acceptor. These hemicyanine derivatives were utilized as photocatalysts in additive/base free oxidative amidation of aromatic aldehydes in mixed aqueous media under visible light irradiation at low catalytic loading. The hemicyanine derivative C4 exhibited recyclability upto four cycles and reusability upto five cycles in oxidative amidation of aromatic aldehydes. Among all the hemicyanine derivatives, C4 shows a high photocatalytic efficiency due to a high singlet oxygen quantum yield. All the mechanism investigations showed involvement of reactive oxygen species generated by the organic triplet photosensitizer based on hemicyanine derivative for carrying out oxidative amidation of aldehyde. Our results will encourage the design of new “metal free” organic photosensitizers and their application in photocatalysis.

Hemicyanine derivatives C1–C4 have been synthesized and utilized as photocatalysts in additive/base free oxidative amidation of aromatic aldehydes in mixed aqueous media under visible light irradiation at low catalytic loading.

Design of Thermochromic Polynorbornene Bearing Spiropyran Chromophore Moieties: Synthesis, Thermal Behavior and Dielectric Barrier Discharge Plasma Treatment

A new class of thermochromic polynorbornene with pendent spiropyran moieties has been synthesized. Functionalization of norbornene monomers with spirobenzopyran moieties has been achieved using Steglich esterification. These new monomeric materials were polymerized via Ring Opening Metathesis Polymerization (ROMP). In spite of their poor solubility, polynorbornenes with spirobenzopyran exhibited thermochromic behavior due to the conversion of their closed spiropyran moieties to the open merocyanine form. Moreover, these polymers displayed bathochromic shifts in their optical response, which was attributed to the J-aggregation of the attached merocyanine moieties that were associated with their high concentration in the polymeric chain. The surface of the obtained polymers was exposed to atmospheric pressure air Dielectric Barrier Discharge (DBD) plasma system, which resulted in the reduction of the surface porosity and converted some surface area into completely non-porous regions. Moreover, the plasma system created some areas with highly ordered J-aggregates of the merocyanine form in thread-like structures. This modification of the polymers’ morphology may alter their applications and allow for these materials to be potential candidates for new applications, such as non-porous membranes for reverse osmosis, nanofiltration, or molecular separation in the gas phase.

A novel colorimetric and fluorescent probe for simultaneous detection of SO32-/HSO3- and HSO4- by different emission channels and its bioimaging in living cells

A novel fluorescent probe (E)-3-ethyl-2-(4-hydroxystyryl)-1,1-di-methyl-1H-benzo-[e]indolium iodide (probe EDB) based on benzo[e]indolium was synthesized, which provided the simultaneous detection of SO₃^2-/HSO₃^- and HSO₄^- ion with different emission channels. Based on the principle of ion-induced rotation-displaced H-aggregates, when treated with NaHSO₄, a fluorescence enhancement at 580nm was observed with the excitation wavelength at 420nm. While, in the advantage of the nucleophilic addition of SO₃^2- to the vinyl group, strong fluorescence was obtained at 455nm when treated with Na₂SO₃ with the excitation wavelength at 320nm, along with obvious color change by naked eyes. So the probe could be applied to sense SO₃^2-/HSO₃^- and HSO₄^- ion via different excited and emission channels simultaneously. The probe was also applicable for fluorescence imagings of bisulfite and hydrosulfate in HeLa cells.

Design and synthesis of a rhodol isomer and its derivatives with high selectivity and sensitivity for sensing Hg2+ and F− in aqueous media

A fluorescent rhodol isomer has developed as a versatile fluorophore for the molecular design of chemosensors and fluorescent tracers.

A Novel Styryldehydropyridocolinium Homodimer: Synthesis and Fluorescence Properties Upon Interaction with DNA

A novel homodimer of the styryldehydropyridocolinium dye (TPTP) has been synthesized and characterized. Free TPTP exhibited low fluorescence quantum yield and large Stokes shift (over 160 nm) in water. However, it showed a significant fluorescence turn-on effect upon intercalation into DNA base pairs. Meanwhile, the fluorescence intensity of the intercalated structures formed by TPTP and DNA decreased quickly upon addition of deoxyribonuclease I, indicating that the dye can be used to monitor deoxyribonuclease I activity and DNA hydrolysis. Electrophoresis analysis revealed that the dye had intercalative binding to DNA and can potentially be used for DNA staining in electrophoresis. Thus, the innate nature of large Stokes shift and excellent fluorescence turn on effect upon interaction with DNA endue the dye with a wide range of applications.

A water soluble copper(ii) complex as a HSO4− ion selective turn-on fluorescent sensor applicable in living cell imaging

A water soluble non-fluorescent biofriendly cell permeable structurally characterised copper(ii) complex (1) selectively senses HSO₄⁻ ions as low as 3.18 × 10⁻⁷ M in water : DMSO (9 : 1, v/v) HEPES buffer at biological pH.

Aggregation studies of dipolar coumarin-153 dye in polar solvents: a photophysical study

Photophysical studies have been carried out to explore the aggregation behavior of coumarin-153 (C153) dye in polar organic solvents of both aprotic and protic nature, namely acetonitrile (ACN) and ethanol (EtOH). No unusual behavior is observed in aprotic ACN solvent, suggesting only the monomers of the dye as the single emitting species in the solution. In protic EtOH solvent, however, the dye shows the presence of multiple emitting species in the solution. The concentration-, temperature- and wavelength-dependent changes in the fluorescence decays, and the time-resolved emission spectra (TRES) and area-normalized emission spectra (TRANES) suggest the coexistence of dye aggregates along with the dye monomers in the EtOH solution. Observed results indicate that the emission spectra of the aggregates are substantially blue-shifted compared to the spectra of the monomers, suggesting the H-aggregation of the dye in the present cases. Time-resolved fluorescence anisotropy, ultrafast fluorescence up-conversion measurements and scanning electron microscopy studies support the aggregation of the dye in EtOH solution. Strong dipole-dipole interaction is supposedly responsible for the aggregation of C153 dye (dipole moment ∼6.4 D) and the polar protic solvent EtOH apparently stabilizes the aggregates through solute-solvent hydrogen bonding interaction, which is not possible in aprotic ACN solvent. This is further supported by the time-resolved fluorescence results in a strongly hydrogen bond donating solvent, 2,2,2-trifluoroethanol. Aggregation of C153 dye observed in the present study in polar protic organic solvent is an intriguing finding, as the dye is widely used as a fluorescent probe for various photochemical studies, where overlooking such aggregation will definitely mislead the observed results.

Ratiometric fluorescent probe for rapid detection of bisulfite through 1,4-addition reaction in aqueous solution

A ratiometric fluorescent probe based on a positively charged benzo[e]indolium moiety for bisulfite is reported. The bisulfite underwent a 1,4-addition reaction with the C-4 atom in the ethylene group. This reaction resulted in a large emission wavelength shift (Δλ = 106 nm) and an observable fluorescent color change from orange to cyan. The reaction could be completed in 90 s in a PBS buffer solution and displayed high selectivity and sensitivity for bisulfite. A simple paper test strip system was developed to detect bisulfite rapidly. Probe 1 was used to detect bisulfite in real samples with good recovery.

A colorimetric and ratiometric fluorescent probe for distinguishing cysteine from biothiols in water and living cells

A highly selective merocyanine-based fluorescent probe was developed, which can significantly distinguish Cys from Hcy and GSH by their kinetic profiles in water and respond to the intracellular Cys.

Development of a cell permeable ratiometric chemosensor and biomarker for hydrogen sulphate ions in aqueous solution

A newly designed benzimidazol-based water soluble ratiometric chemosensor selective for HSO₄⁻ ions behaves as an efficient biomarker for the detection of the distribution of HSO₄⁻ ions in living cells in HEPES buffer (1 mM; water : ethanol (v/v), 98 : 2).