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Acute pancreatitis (AP) is an acute inflammation of the pancreas, which is accompanied by necrotizing inflammatory response and tissue edema. As a vital enzyme secreted by pancreas, pancreatic lipase (PL) has been established that the increase of its expression is closely related to the prevalence and seriousness of AP. Therefore, there is an urgent need to develop efficient tools for detecting the fluctuation of PL in AP, which will promote understanding of the physiological and pathological effects of AP. In this work, we firstly report an intramolecular charge transfer (ICT)-based near-infrared (NIR) fluorescence probe, NIR-PLP , which featured excellent selectivity, sensitivity, and high biocompatibility. Moreover, the NIR-PLP was successfully used to detect the fluctuation endogenous PL in AP cell model respectively caused by L-arginine and caerulein, and further evaluated fluorescence enhancement triggered by exogenous PL in zebrafish. Most importantly, we successfully achieved in situ monitoring of PL increased in AP mouse model induced by L-arginine with the assistance of probe NIR-PLP. These findings indicate the potential clinical utility of using the NIR-PLP probe to investigate the occurrence, progression, and treatment of AP. [Display omitted] • A novel near-infrared fluorescent probe NIR-PLP for pancreatic lipase was fabricated. • The probe NIR-PLP displayed high selectivity and sensitivity toward pancreatic lipase. • NIR-PLP was used for imaging pancreatic lipase in cells and zebrafish. • NIR-PLP was utilized to in situ image pancreatic lipase in acute pancreatitis model. [ABSTRACT FROM AUTHOR]

Alkyne is a versatile functional group in organic chemistry, and is able to undergo a wide variety of reactions and interactions. Featuring a reactive functional group, alkyne participates in many organic reactions and hence a sharp rise in the interest of utilizing the alkyne functionality has made it an inevitable synthon in a wide domain of purposes and one of such purposes is molecular recognition. On account of this, two pyridine-derived scaffolds, 5 and 7, containing identical molecular cores but different appendages, viz., terminal alkyne (5) and internally 1,3-conjugated alkyne units (7), are successfully synthesized. Both the compounds are subjected to metal ion sensing at the molecular level and are found to bind Cu2+ and Hg2+ ions with different functionalities. Compounds 5 and 7 interact with Cu2+ by the pyridine N and the two adjacent amide N's in a tripodal fashion, whereas they interact with Hg2+ by their respective open-end and closed-end alkyne units. The terminal alkynes in 5 undergo chemical reaction in the presence of Hg(ClO4)2·H2O and get converted to a ketone functionality, while the internally conjugated 1,3-dialkyne unit in 7 acts as a binding unit for a Hg2+ ion. Both experimental studies and theoretical (DFT) calculations have converged on the result that terminal alkynes cannot function as a chemosensor for Hg2+ ions, although they can respond by functional group transformation, whereas cyclic internally conjugated alkynes can perform as potential Hg2+ sensors. The combination of Cu2+ and Hg2+ ions has been used to generate a molecular system exhibiting the OR logic operation. The limits of detection (LODs) of Cu2+ ions, obtained for 5 and 7, are 5.5 × 10−7 M and 5.2 × 10−7 M, respectively, and that of the Hg2+ ion for 7 is 4.4 × 10−7 M. The synthesized probes, as well as their complexes, are stable around neutral pH and the probes retain their sensitivity within a temperature window of 25–80 °C. This creates an avenue for differential recognition of multiple heavy metal ions simultaneously with similar molecular motifs. [ABSTRACT FROM AUTHOR]

As a highly toxic commercial product, phosgene is a potentially serious threat to public safety, so a convenient and reliable phosgene detection method is urgently needed. In this work, a new through-bond energy transfer (TBET) based fluorescent probe TPE–RhodEA has been developed as a fast, susceptible, and selective sensor of phosgene. TPE–RhodEA is based on a tetraphenylethylene–rhodamine scaffold and uses ethylenediamine as the phosgene recognition unit. The probe showed blue fluorescence in acetonitrile due to the occlusion of rhodamine diamine. After reacting with phosgene, rhodamine diamine undergoes ring-opening, and TPE–RhodEA exhibits apparent red fluorescence. Due to the specific ring-opening reaction, TPE–RhodEA shows a distinct ratiometric fluorescence response to phosgene with a significant pseudo Stokes shift (267 nm), an immediate response (less than 2 min), and a low detection limit (0.54 ppm). Furthermore, TPE–RhodEA-loaded test TLC strips were prepared and enabled the direct visualization and reliable quantitative analysis of phosgene by combining fluorescent test TLC strips with an easily accessible color recognition app on a smartphone. [ABSTRACT FROM AUTHOR]

A new fluorescent probe TPE-GHK was synthesized containing a tetrastyrene (TPE) derivative as fluorophore and classical tripeptide (Gly-His-Lys-NH2) as a receptor based on the aggregation-induced emission (AIE) mechanism. TPE-GHK displayed high selectivity and rapid fluorescent "turn-on" response to Hg2+ among other competitive metal ions. The 2:1 complex binding mechanism of TPE-GHK toward Hg2+ was verified by fluorometric titration, Job's plots, and ESI-HRMS spectra. The fluorescent emission showed a good linear response in the range of 0–1.0 μM with the low detection limit of 28.6 nM. Meanwhile, TPE-GHK exhibited the excellent biocompatibility and low toxicity and was successfully applied in monitoring Hg2+ in living CAKI 2 cells, which demonstrated its potential application in environment and biological science. More importantly, TPE-GHK could be used to detect Hg2+ in two real water samples and also was successfully designed as test strips. [ABSTRACT FROM AUTHOR]

The sol-gel technology allows for the development of materials for nonlinear optics and photonics through the synthesis of multifunctional ceramic materials. Although the nature of the amorphous matrix allows the material to be doped with a large amount of the active components without quenching, it may affect the spectroscopic characteristics of the dye (e.g., result in a shift of absorption and emission peaks with drying time, presumably with a change of concentration). This study presents the material (SiO2 impregnated with organic dyes—Rhodamine 6G and 19) with tunable emissions obtained by the authors upon annealing at different temperatures within the range of 100–300 °C. Possible observed effects were discussed based on spectroscopic properties and thermal studies of the synthesized material. Concerning annealing at different temperatures, an effect on concentration was observed. At the same time, a longer heating process at 300 °C revealed a protective function of sol-gel-derived silica for the organic dye; the longer heating did not cause any further significant changes in the dye's emission, which indicates the preservative role of the sol-gel layers. Furthermore, etching tests of thin layers were conducted, resulting in smooth side edges of the waveguide. The tests have shown that it is possible to use dye-doped sol-gel layers as active components in photonics platforms. [ABSTRACT FROM AUTHOR]

A novel lysosome-targeting PEGylated polyester-based fluorescent pH nanosensor is fabricated by the combination of ring-opening copolymerization (ROCOP), side-group modification and subsequent self-assembly. First, a key target amphiphilic copolymer carrier for rhodamine (Rh) pH indicator is synthesized in a facile manner by the ROCOP of phthalic anhydride with allyl glycidyl ether using mPEG-OH and t-BuP1/Et3B as the macroinitiator and binary catalyst, respectively. Subsequently, Rh moieties are covalently attached on the polymer chain with controllable grafting degree via an efficient thiol-ene click reaction. Concurrently, the effect of catalyst systems and reaction conditions on the catalytic copolymerization performance is presented, and the quantitative introduction of Rh is described in detail. Owing to its amphiphilic characteristics, the rhodamine-functionalized polyester-based block copolymer can self-assemble into micelles. With the covalent incorporation of Rh moieties, the as-formed micelles exhibit excellent absorption and fluorescence-responsive sensitivity and selectivity towards H+ in the presence of various metal cations. Moreover, the as-prepared micelles with favorable water dispersibility, good pH sensitivity and excellent biocompatibility also display appreciable cell-membrane permeability, staining ability and pH detection capability for lysosomes in living cells. This work provides a new strategy for the facile synthesis of novel biocompatible polymeric fluorescent pH nanosensors for the fluorescence imaging of lysosomal pH changes. [ABSTRACT FROM AUTHOR]

A rhodamine-based fluorescent polymer P(MMA-co-RB) has been synthesized via an intermediate NCO-containing polymer generated by the Lossen rearrangement reaction. The fluorescent property of P(MMA-co-RB) with regard to metal ions, such as Cu2+, Fe3+, Cr3+, Al3+, Zn2+, Co2+, Sn2+ and Ag+, was studied by fluorescence emission spectroscopy. The results demonstrate that the fluorescence intensity of P(MMA-co-RB) decreased gradually with an increase of the concentration of Cu2+ ion. Furthermore, a test strip made of P(MMA-co-RB) can be used for fast and quantitative determination of Cu2+ ion. In the presence of Cu2+ ion, the sensory tester undergoes distinct changes in fluorescence intensity and visible color. [ABSTRACT FROM AUTHOR]

ObjectivePerivascular cells, including pericytes, macrophages, smooth muscle cells, and other specialized cell types, like podocytes, participate in various aspects of vascular function. However, aside from the well-established roles of smooth muscle cells and pericytes, the contributions of other vascular-associated cells are poorly understood. Our goal was to ascertain the function of perivascular macrophages in adult tissues under nonpathological conditions.Approach and resultsWe combined confocal microscopy, in vivo cell depletion, and in vitro assays to investigate the contribution of perivascular macrophages to vascular function. We found that resident perivascular macrophages are associated with capillaries at a frequency similar to that of pericytes. Macrophage depletion using either clodronate liposomes or antibodies unexpectedly resulted in hyperpermeability. This effect could be rescued when M2-like macrophages, but not M1-like macrophages or dendritic cells, were reconstituted in vivo, suggesting subtype-specific roles for macrophages in the regulation of vascular permeability. Furthermore, we found that permeability-promoting agents elicit motility and eventual dissociation of macrophages from the vasculature. Finally, in vitro assays showed that M2-like macrophages attenuate the phosphorylation of VE-cadherin upon exposure to permeability-promoting agents.ConclusionsThis study points to a direct contribution of macrophages to vessel barrier integrity and provides evidence that heterotypic cell interactions with the endothelium, in addition to those of pericytes, control vascular permeability.

Stimulated emission depletion (STED) nanoscopy allows observations of subcellular dynamics at the nanoscale. Applications have, however, been severely limited by the lack of a versatile STED-compatible two-colour labelling strategy for intracellular targets in living cells. Here we demonstrate a universal labelling method based on the organic, membrane-permeable dyes SiR and ATTO590 as Halo and SNAP substrates. SiR and ATTO590 constitute the first suitable dye pair for two-colour STED imaging in living cells below 50 nm resolution. We show applications with mitochondria, endoplasmic reticulum, plasma membrane and Golgi-localized proteins, and demonstrate continuous acquisition for up to 3 min at 2-s time resolution.

Metal–organic frameworks have great potential in the field of proton conducting materials and fluorescent probes due to their structural tunability and designability. A novel water-stable metal organic framework material [Cd2(Hdpb)(H2O)3] (Cd-MOF) was synthesized based on H5dpb (H5dpb = 3,5-diphosphonobenzoic acid) and Cd2+ ions. Cd2+ ions are connected with phosphonates and carboxyl groups of H5dpb to form an infinitely extended 1D chain, which is further connected by the Hdpb4− ligand and coordinated water to form a three-dimensional network structure. There are hydrogen bond networks in the 3D structure of the Cd-MOF, which are favorable for proton transfer, achieving its maximum proton conductivity of 2.97 × 10−3 S cm−1 at 338 K and 98% relative humidity (RH). To realize its application in fuel cells, the Cd-MOF was introduced into the chitosan (CS) matrix, and a series of composite membranes (Cd-MOF@CS-X) with high proton conductivity were obtained. The results of AC impedance show that the proton conductivity of Cd-MOF@CS-5 reaches 3.55 × 10−1 S cm−1 at 358 K and 98% RH, which is comparable to the highest values reported for MOF-polymer complexes. Moreover, the Cd-MOF can be used as a selective fluorescent probe for pyridine detection, and its detection limit can reach 1.0 × 10−6 M. A bifunctional MOF with proton conduction and pyridine recognition is reported for the first time, and has important reference value for the practical application of functional MOFs in both electrochemical and luminescence sensing. [ABSTRACT FROM AUTHOR]

Fluorene-based analogues of fluorescein, rhodol, and rhodamine exhibit absorption and fluorescence beyond 800–900 nm in water, 300–400 nm red-shifted compared to the original oxygen-bridged xanthene dyes, giving potential access to low molecular weight fluorescent markers for the second biological window (NIR-II, ca. 1000–1350 nm). [ABSTRACT FROM AUTHOR]

The spiropyran derivatives are known for their good photochromic properties. These photochromic compounds are isomerized between two forms; merocyanine is the open-ring form and spiropyran is the closed-ring form. In this work, two spiropyran derivatives (compounds 1 and 2) with the N-alkynyl functional group are prepared. The click reactions of these spiropyran derivatives with 1-azido-4-nitrobenzene and (azidomethyl)benzene are studied. For this purpose, 3,3-dimethyl-2-methylene-1-prop-2-ynyl-2,3-dihydro-1H-indole is synthesized, which is then reacted with 3- and 5-nitrosalicylaldehyde. The FT-IR, 1H-NMR, and 13C-NMR spectra of the reaction products are used for their characterization. The solutions of the products in methanol are prepared, and their UV–visible spectra are investigated. The darkening of the crystals of compound 1 upon exposure to the UV irradiation indicates that the spiro C–O bond in this compound is weaker than that in compound 2, which is due to the presence of the nitro group in the para position relative to this bond, and consequently, the stabilization of the open-ring form. [ABSTRACT FROM AUTHOR]

A highly sensitive and selective optical chemosensor (Arg-Rhoen) for determination of Au3+ was prepared by covalent immobilization of rhodamine ethylenediamine on agarose gel. Spectrophotometric studies of complex formation, chemical structures and purity of the hydrogel sensor were carried out using TGA, NMR, TEM, and IR. The complexation study results indicated that this probe can selectively detect Au3+ via a metal ion chelation-induced ring-opening reaction, and then caused a remarkable colour change from colourless to pink and a strong fluorescence enhancement. Theoretical DFT calculation results suggested that the hydrogel sensor Arg-Rhoen formed stable complexes with Au3+ through a large number of cation–dipole interactions. Reusability has been established by repeatedly dipping and rinsing the hydrogel in aqueous Au3+ and EDTA in basic solutions. We believe that this approach may provide an easily measurable and inherently sensitive method for Au3+ detection in environmental and biological applications. [ABSTRACT FROM AUTHOR]

Due to the energy gap law, the direct fabrication of efficient organic afterglow materials with long emission wavelengths at ambient conditions remains challenging. Here, luminescent dopants with moderate kRISC values of 100–101 s−1 are designed to harvest triplet energies, simultaneously improving afterglow efficiency and maintaining emission lifetimes >0.1 s. Organic matrices with large dipole moments are selected to populate the triplet excited states of the luminescent dopants and suppress their nonradiative decay and quenching. The dopant‐matrix systems exhibit TADF‐type organic afterglow with quantum efficiency of 20% to 60% and emission wavelengths exceeding 600 nm. Because of their singlet excited state nature, the TADF‐type afterglow emitters can efficiently transfer excited energy to rhodamine B or cyanine 5.5 fluorescence dyes for the construction of red and near‐infrared afterglow materials which display promising bioimaging applications. [ABSTRACT FROM AUTHOR]

Herein, we have reported two isostructural mononuclear metal complexes [M(HL)2(ClO4)2], wherein, M= Co2+ (viz. SN‐1) and Ni2+ (viz. SN‐2) and HL is NNO donor Schiff‐base ligand i. e. ((E)‐2‐methyl‐2‐((pyridin‐2‐ylmethylene)amino)propan‐1‐ol) for unveiling as molecular sensor for S2− (sulphide) like hazardous entity. The molecular probes have been characterized by SCXRD, 1H‐NMR, FT‐IR, HRMS etc. X‐ray diffraction studies confirm the mono‐nuclear structures of both the complexes. Interestingly, SN‐1 exhibited remarkable sensitivity towards S2− by naked eye colour change in purely aqueous medium with detection limit of 33.5 nM and binding constant of 11.05 × 108 M−1 while the SN‐2 didn't show any subtle chromogenic changes upon interaction with the targeted analyte. Judicious choice of metal centre plays a pivotal role for such discriminative interacting behaviour. Spectroscopic and DFT studies shed light on the mechanistic pathway of host‐guest interaction, indicating a S2− mediated chemodosimetric approach following HSAB principle. Impressively, the SN‐1 has also been explored towards fabrication of test strips for on‐field detection of H2S/S2−via. "Dip‐Stick" approaches. In a nutshell, the presently developed simple mono‐nuclear metal complex can be utilised for detecting gasotransmitter like H2S/S2− from purely aqueous medium that may be helpful in fabricating "point‐of‐care" devices in coming days for better understanding of H2S as a key role maker in various health related issues. [ABSTRACT FROM AUTHOR]

Chemiluminescent iridium‐based sensors which demonstrate oxygen dependent responses have been developed. The molecular probes, named IrCL‐1, IrCL‐2 and IrCL‐3 consist of oxygen‐sensitive iridium complexes attached to a spiroadamantane 1,2 dioxetane and operate via energy transfer from the chemiexcited benzoate to the corresponding iridium(III) complex. Complexing the iridium(III) center with π‐extended ligands results in emission in the biologically relevant, near‐infrared (NIR) region. All probes demonstrate varying oxygen tolerance, with IrCL‐1 being the most oxygen sensitive. These probes have been further utilized for in vitro ratiometric imaging of oxygen, as well as for intraperitoneal, intramuscular and intratumoral imaging in live mice. To our knowledge, these are the first iridium‐based chemiluminescent probes that have been employed for in vitro ratiometric oxygen sensing, and for in vivo tumor imaging. [ABSTRACT FROM AUTHOR]

In the present paper, density functional theory (DFT) has been applied to the study of the activation mechanism of a new selenium azo‐rhodamine (azoSeRho) in presence of the tripeptide thiol, glutathione (GSH), as potent activatable photosensitizer to be employed in photodynamic therapy. The introduction of the azo group into the conjugated system of the seleno‐rhodamine dye and its reaction with GSH allow the selective formation of the active photosensitizer, SeRho. Furthermore, DFT calculations have allowed to shed light on the activation mechanism of the azoSeRho photosensitizer when molecular oxygen is present and hydrogen peroxide is formed. This study is the first theoretical investigation revealing how the reductive cleavage of the azo moiety by GSH occurs. Time‐dependent DFT approach has been used to evaluate the chalcogen‐substitution effect on the structures and photophysical properties of the azo derivatives and, then, on the activated photosensitizers. [ABSTRACT FROM AUTHOR]

Background: The treatment of caries in dentine poses the challenge of balancing adequate caries removal to prevent residual caries and excessive sound dentine removal. No diagnostic tool is available to define the caries removal limit clinically. This study aimed to determine the efficiency of visual-tactile, caries detector dye (CDD), and laser fluorescence (LF) device methods for diagnosing residual caries after cavity preparation., Method: The study was conducted as a three-arm, double-blinded, parallel-group randomized trial at the Restorative Dentistryclinics of a teaching hospital in northeastern Nigeria. Individualized carious lesions in dentine were randomly allocated to three groups of residual caries diagnosis methods, A (visual-tactile), B (CDD), and C (LF). All carious lesions had caries excavation and cavity preparation using the visual-tactile method. Main outcome measures were based on the assessment of residual caries of prepared cavities in groups B and C with CDD and LF (DIAGNOdent Pen) respectively, and bacterial culture growth of dentine samples collected from all (A, B, and C) the preparedcavities., Design: Three-arm, double-blinded, parallel group randomized trial. A centralized randomization, into three groups A, B, and C, used opaque envelopes containing names of diagnostic methods allocated to teeth in the trail., Setting: Restorative Dentistry clinics of a teaching hospital in northeastern Nigeria., Participants: Ninety patients with dental caries in dentine. All 90 patients met the requirements for the study., Intervention: Carious lesions were excavated, and cavity preparation was performed via the visual-tactile method. Prepared cavities in groups B and C were assessed for residual caries with CDD and LF (DIAGNOdent Pen), respectively, by a blinded independent investigator. Dentine samples were obtained from all the prepared cavities (A, B, and C) and subjected to bacterial culture. Teeth were restored and follow-up was not required., Main Outcome Measures: The presence or absence of residual caries staining by CDD and fluorescence by DIAGNOdent in prepared cavities of groups B and C, respectively; the presence or absence of bacterial culture growth for all three groups., Results: Ninety participants (mean age 31.6 ± 7.480), each with one tooth with a deep carious lesion were randomized. The visual-tactile method had a specificity of 100%, CDD had 100% sensitivity and 92.9% specificity, and DIAGNOdent had 100% sensitivity and 100% specificity when measured against bacterial cultures. The positive predictive value for CDD (50%) was half that for DIAGNOdent (100%). The negative predictive value was the lowest (90%) for the visual-tactile method. The accuracy was highest (100%) for DIAGNOdent. There was perfect agreement between the DIAGNOdent and bacteriological tests (kappa = 1.00), whereas the CDD had an above-random level of agreement (kappa = 0.63)., Conclusions: All three residual caries evaluation methods were efficient, independently, in detecting residual caries in prepared cavities. DIAGNOdent was the most specific of the tested modalities and had the highest agreement with the bacteriological confirmatory test., Trial Registration: PanAfrican Clinical Trial Registry (PACTR202309545839091), registered on 1st September 2023., Competing Interests: Declarations. Ethics approval and consent to participate: Ethical approval (UMTH/REC/21/948) was obtained from the Research and Ethics Committee of the University of Maiduguri Teaching Hospital. Written informed consent was obtained from all study participants. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

MitoTEMPO (MT) and Visomitin (SKQ1) are regareded as mitochondria-targeted antioxidants, which inhibit production of mitochondrial reactive oxygen species (ROS). However, the differences in function between MT and SKQ1 remain unexplored. Herein, we investigated the differential potency of MT and SKQ1 in mitigating oxidative stress under different conditions. The results indicated that high levels of SKQ1 induced cell death. The appropriate concentrations of MT and SKQ1 can prevent or rescue cell damage triggered by hydrogen peroxide (H 2 O 2 ) and menadione (MEN). MT and SKQ1 reduced ROS levels and reversed the down-regulation of antioxidant defence genes and enzymes. These effects can alleviate the damage to lipids, proteins, and deoxyribonucleic acid (DNA) caused by oxidative stress and restore adenosine 5' triphosphate (ATP) generation. Subsequently, we found that MT administration in ischemic reperfusion kidney injury in mice provided superior renal protection compared to SKQ1, as evidenced by reduced plasma levels of kidney injury markers, improved renal morphology, decreased apoptosis, restored mitochondrial function, and enhanced antioxidant capacity. Overall, our findings suggest that MT is safer and has greater potential than SKQ1 as a therapeutic agent to mitigate oxidative stress damage or oxidative renal injury., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Guohua Gong reports financial support was provided by Medical Health Science and Technology Project of Zhejiang Provincial Health Commission. Guohua Gong reports was provided by National Natural Science Foundation of China. Guohua Gong reports was provided by Key Laboratory of School of Laboratory Medicine and Life Sciences, Wenzhou Medical University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In this study, mesoporous materials (MCM-41 and MCM-48) were synthesized and functionalized with an acid group through a post-synthetic modification method. A mononuclear Zn complex [Zn(dmp)Cl 2 ] (dmp = neocuprine) was also prepared and incorporated into a functionalized mesoporous material. Extensive characterization of the material married was carried out using techniques such as X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the characteristics of modified materials. The characterization results revealed that the post-synthetic modification did not alter the phase purity, crystallinity, or morphology of the mesoporous materials while confirming the successful grafting of the desired sulphonic acid functionality and Zn complex. The Zn complex-grafted-functionalized mesoporous materials were then assessed for their photo-degradation using methylene blue (MB) and rhodamine B (RB). The results demonstrated exceptional photo-degradation efficiency of the modified materials under sunlight. Within 15 min, 10 mg/ml of dye concentration, and adsorbent dosage 0.15 mg/ml and 0.1 mg/ml, degradation efficiencies of 99% and 92%, were achieved for MB using M-48-S-Zn 1 and M-41-S-Zn 1 , respectively. Similarly, 91% and 78% degradation rates were achieved within 30 min for RB using the same materials. The modified mesoporous materials exhibited a remarkable degradation performance even in challenging environments, including highly acidic, basic, and salt-concentrated conditions. This highlights the versatility and robustness of the modified materials in different environmental scenarios., Competing Interests: Declarations. Ethical approval and consent to participate: This article does not contain any study with human and animals performed by any of the author. Consent to participate: Not applicable. Consent for publication: The authors have consented to the submission of the study to the journal. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Toward the development of a sustainable utilization strategy for adsorption materials, a starch-based adsorbent starch-chitosan-tannic acid (St-CTS-TA) with a three-dimensional (3D) structure was fabricated in water via electrostatic and hydrogen bonding reactions between St, CTS, and TA without using toxic reducing agents or special instruments. St-CTS-TA demonstrated a high specific surface area of 37 m 2 /g as well as a mesoporous/macroporous distribution ranging from 30 to 80 nm, which enhanced the mass transfer of adsorbate and the exposure of catechol groups in TA. The Langmuir isotherm adsorption model revealed that the highest adsorption capacities of St-CTS-TA for Fe 3+ and Co 2+ were 1678.2 and 944.8 mg/g, respectively. Surprisingly, the specific surface area of St-CTS-TA increased from 37 to 87 and 42 m 2 /g after Fe 3+ and Co 2+ adsorption, respectively, and the resulting St-CTS-TA-Fe and St-CTS-TA-Co could continuously adsorb basic fuchsin (BF) and rhodamine B (RhB). The adsorption capacities of St-CTS-TA-Fe and St-CTS-TA-Co for BF/RhB were found to be 1854.79/401.19 mg/g and 2229.77/537.49 mg/g, respectively, based on the Langmuir isotherm adsorption model., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Minimally invasive surgery continues to prioritize patient safety by improving imaging techniques and tumor detection methods. In this work, an all-optical alternative to the current image based techniques for in vitro minimally invasive procedures has been explored. The technique uses a highly fluorescent marker for the surgical needle to be tracked inside simulated tissues. A series of markers were explored including inorganic (Perovskite and PbS) and organic (carbon dots) nanoparticles and organic dye (Rhodamine 6G) to identify layers of different stiffnesses within a tissue. Rhodamine 6G was chosen based on its high fluorescence signal to track 3D position of a surgical needle in a tissue. The needle was tracked inside homogeneous and inhomogeneous gelatin tissues successfully. This exploratory study of tissue characterization and needle tip tracking using fluorescent markers or photoluminescence technique show potential for real-time application of robot-assisted needle insertions during in vivo procedures.

Background: Infected dentinal tubules are a possible source of bacteria that are responsible for the failure of root canal treatment. Therefore, disinfection of dentinal tubules by increasing the penetration of the irrigation solution is important for success in retreatment cases. This study utilized confocal laser scanning microscopy (CLSM) to assess and compare the impact of XPR, ultrasonic irrigation (UI) and sonic activation (SA) on NaOCl penetration into dentinal tubules following endodontic retreatment., Methods: A total of forty mandibular premolars were enrolled in this investigation. Following root canal preparation up to ProTaper X3 file (30/0.07), root canals were obturated with gutta-percha and bioceramic root canal sealer with single cone technique. The root canal filling materials were removed using ProTaper nickel-titanium rotary retreatment files until the working length was reached. The retreatment procedure was finalized using the ProTaper Next X4 (40/0.06). The teeth were divided into four groups based on the irrigation activation technique: control (conventional needle irrigation), SA, UI and XPR. During the final irrigation procedure, Rhodamine B dye was introduced to 5% NaOCl for visualization via CLSM. Subsequent to image acquisition, the maximum penetration, penetration percentage, and penetration area were calculated. Data were statistically analyzed using the Kruskal-Wallis, Friedman, and Bonferroni Dunn multiple comparison tests through R software (p < 0.05)., Results: In the middle third, UI yielded a significantly higher penetration percentage than the control group (p < 0.05). The UI and XPR groups showed increased penetration percentages in the coronal and middle thirds compared with the apical third (P < 0.05). Maximum penetration was notably reduced in the apical third than in comparison with the coronal and middle thirds in all groups (p < 0.05). In the control, SA and XP groups, the penetration area was ranked in descending order as coronal, middle and apical (p < 0.05). Conversely, in the ultrasonic group, the penetration area was significantly lower in the apical third than in the middle and coronal thirds (p < 0.05)., Conclusions: UI enhanced the penetration percentage in the middle third of the root compared with that in the control group. XPR and SA showed no significant effect on NaOCl penetration following retreatment., (© 2024. The Author(s).)

Random lasing (RL) is an optical phenomenon that arises from the combination of light amplification with optical feedback through multiple scattering events. In this paper, we present our investigations of RL generation from human blood samples. We tested mixtures of rhodamine B dye solutions with different blood components, including platelets, lymphocytes, erythrocytes, and whole blood. Intense coherent RL was obtained in all cases at relatively low pump thresholds, except for erythrocytes. We also studied the potential of RL signal analysis for biosensing applications using blood samples from healthy individuals and patients suffering from Chronic Lymphocytic Leukemia (CLL). CLL is a blood disease characterized by a high count of lymphocytes with significant morphological changes. A statistical analysis of the RL spectra based on principal component and linear discriminant analyses was conducted for classification purposes. RL-based sample discrimination was conducted for whole blood, platelet, and lymphocyte samples, being especially successful (86.7%) for the latter. Our results highlight the potential of RL analysis as a sensing tool in blood.

A recent theoretical study proposed that two-quantum (2Q) two-dimensional (2D) electronic spectroscopy should be a background-free probe of post-Hartree-Fock electronic correlations. Testing this theoretical prediction requires an instrument capable of not only detecting multiple transitions among molecular excited states but also distinguishing molecular 2Q signals from nonresonant response. Herein we describe a 2Q 2D spectrometer with a spectral range of 300 nm that is passively phase stable and uses only beamsplitters and mirrors. We developed and implemented a dual-chopping balanced-detection method to resolve the weak molecular 2Q signals. Experiments performed on cresyl violet perchlorate and rhodamine 6G revealed distinct 2Q signals convolved with nonresonant response. Density functional theory computations helped reveal the molecular origin of these signals. The experimental and computational results demonstrate that 2Q electronic spectra can provide a singular probe of highly excited electronic states. [ABSTRACT FROM AUTHOR]

Silver dendrites were obtained on Cu plate by a classic galvanic displacement process. The process of preparing Ag particles was performed at different immersion times in AgNO3 solution, and the best process parameters were selected according to the enhancement effect of the Raman spectra of Rhodamine 6G. Ag-Cu substrates were chosen for a Surface-enhanced Raman scattering (SERS) study of biocomplexes because their preparation is cost effective and simple, and the relative homogeneous signal enhancement on the prepared silver SERS-active substrate was obtained. The rapid process of surface preparation was applied to identify the mode of coordination. Biocomplexes of Co and Ni ions with adenosine triphosphate form in neutral pH were immersed on the Ag dendrites, and SERS spectra of these compounds were collected. This research work was carried out in order to determine different types of coordination in the same pH conditions and relatively low concentration using SERS which is an emerging and promising technique for the determination of coordination types in biocomplexes. [ABSTRACT FROM AUTHOR]

In this paper, we show that Inkjet Printing can be successfully applied to external-cavity vertically emitting thin-film organic lasers and can be used to generate a diffraction-limited output beam with an output energy as high as 33.6 μJ with a slope efficiency S of 34%. Laser emission shows to be continuously tunable from 570 to 670 nm using an intracavity polymer-based Fabry-Perot etalon. High-optical quality films with several μm thicknesses are realized, thanks to ink-jet printing. We introduce a new optical material where EMD6415 commercial ink constitutes the optical host matrix and exhibits a refractive index of 1.5 and an absorption coefficient of 0.66 cm-1 at 550-680 nm. Standard laser dyes like Pyrromethene 597 and Rhodamine 640 are incorporated in solution to the EMD6415 ink. Such large size "printed pixels" of 50mm² present uniform and flat surfaces, with roughness measured as low as 1.5 nm in different locations of a 50 μm × 50 μm AFM scan. Finally, as the gain capsules fabricated by Inkjet printing are simple and do not incorporate any tuning or cavity element, they are simple to make, have a negligible fabrication cost, and can be used as fully disposable items. This work opens the way towards the fabrication of really low-cost tunable visible lasers with an affordable technology that has the potential to be widely disseminated. [ABSTRACT FROM AUTHOR]

Environmentally sensitive fluorescent probes (including AIEgens) play pivotal roles in numerous biological studies. Many of these functional materials are developed based on the twisted intramolecular charge transfer (TICT) mechanism. However, the TICT tendency of dialkylated amino groups in biocompatible main‐stream fluorophores (i.e., coumarins and rhodamines) is weak, limiting their sensitivities. Herein, by replacing dialkylated amino donors with an N‐methylpyrrole group to enhance TICT, a simple and general method to engineer highly environmentally sensitive fluorescent probes is reported. This method yields a platter of colorful fluorescent probes that demonstrates outstanding polarity and viscosity sensitivity with large turn‐on ratios (up to 191 times for polarity and 14 times for viscosity), as well as distinct aggregation‐induced emission (AIE) characteristics. The utilities of these probes in both wash‐free bioimaging and protein detections are also successfully demonstrated. It is expected that this molecular design strategy will inspire the creation of many environmentally sensitive probes. [ABSTRACT FROM AUTHOR]

An abnormal level of SO2 is closely related to many diseases. Therefore, developing an effective method for the detection of SO2 in biological environments has important physiological and pathological significance. In this work, a new fluorescent probe (CA-SO2) was designed and synthesized for efficiently and specifically detecting SO2 derivatives through nucleophilic addition reaction. The novel fluorescent probe (CA-SO2) showed high selectivity, fast response time (within 50 s), and low detection limit (LOD = 75 nM). Furthermore, after adding SO2 derivatives to the probe solution, the color of the solution changes from orange to colorless, which allows "naked eye" detection for SO2. Moreover, the probe has a large Stokes shift (129 nm) and excellent biocompatibility. The probe has been successfully applied to the detection of SO2 derivatives in living cells and zebrafish. [ABSTRACT FROM AUTHOR]

A supramolecular dye-capture system comprising anionic amidosquaraine guest and macrocyclic tetralactam host exhibits nanomolar affinity and "turn on" visible fluorescence. Utility is demonstrated with a new fluorescent assay for liposome leakage induced by the biomedically important enzyme phospholipase A2. [ABSTRACT FROM AUTHOR]

[Display omitted] Water contamination from heavy metal ions is a major global environmental concern. Adsorbents based on biomaterials have been demonstrated to possess remarkable removal efficiency for metal ions, but the adsorption model of biosorbents is not clear and much efforts should be devoted to study the adsorption behaviors and understand the adsorption mechanism. The multifunctional rhodamine-modified chitosan (RMC) hydrogel for Hg2+ adsorption with fluorescent turn-ON properties was fabricated through grafting the rhodamine-modified poly (ethylene glycol) benzaldehyde (RM-PEG) onto the hydrogel network serving as the fluorescence/colorimetric sensing receptor. The adsorption behaviors and colorimetric sensing mechanism of RMC hydrogel towards Hg2+ were investigated in detail. RMC hydrogel can remove more than 96.5% of Hg2+ from aqueous solution with significant fluorescence response and colorimetric change. The high adsorption selectivity and colorimetric sensing mechanism of RMC hydrogel towards Hg2+ can be explained by the hard and soft acid/base (HSAB) theory. The O atom in hydroxyl and carbonyl groups together with the N atom in amine/imine groups of RMC hydrogel play a vital role in the adsorption of Hg2+, while the colorimetric response and fluorescence enhancement of the hydrogel after adsorption are attributed to the specific spiro-lactam structure of rhodamine moieties. The adsorption isotherms and kinetics were investigated and well described by Freundlich isotherm and pseudo-second-order kinetic model. Furthermore, RM-PEG showed low cytotoxicity towards mouse embryonic fibroblast cells and RMC hydrogel can be used as a fluorescent pH indicator from 4.2 to 7.4, demonstrating the potential applications of RMC hydrogel in biological diagnosis. [ABSTRACT FROM AUTHOR]

A microfluidic nanopaper-based analytical device (μNPAD) has been prepared for the determination of cholesterol by using triangular silver nanoprisms (T-AgNPrs). We have developed a simple enzyme-based biosensor that can detect cholesterol by a colorimetric reaction based on the etching of T-AgNPrs. In the presence of cholesterol and cholesterol oxidase (ChOx), H2O2 was produced which etched the T-AgNPrs. As a result, after the etching process, a blue shift occurred and a color change from blue to light orange was observed. Based on this phenomenon, the amount of cholesterol was obtained based on UV-vis spectroscopy and μNPAD. A linear calibration curve in the range of 0.10–4.0 mM was obtained with a detection limit of 0.065 mM and a correlation coefficient (R2) of 0.993 using a UV-visible spectrophotometer. In the case of μNPAD, cholesterol concentration from 0.20 to 3.0 mM can be used with a detection limit of 0.14 mM and a correlation coefficient (R2) of 0.985. The T-AgNPr detection system showed high selectivity to cholesterol and no color change was observed in the presence of other interferences. The proposed μNPAD based on T-AgNPrs can be used in the applications of point-of-care diagnostics. [ABSTRACT FROM AUTHOR]

Graphene oxide–rhodamine B hydrazide (GO-RhB) nanocomposite was prepared by a simple chemical method and characterized by various spectroscopic and analytical techniques. GO-RhB nanocomposite potentially detects Cr3+ ion (excitation/emission = 550 nm/572 nm) via fluorescence turn "on–off" approach. This composite showed high binding affinity (106 M−1) with Cr3+ and a+ limit of detection (LOD) down to picomolar concentration (LOD = 85.6 pM). As far as we know, this is the first report for the sensing of Cr3+ ion at picomolar concentration. GO-RhB selectively senses Cr3+ ion without any interference of other coexisting metal ions. In addition, this composite exhibited the dynamic nature of quenching in the presence of Cr3+ ion, which is confirmed by the Stern–Volmer plot, fluorescence temperature profiles, and decay time experiments. The GO-RhB nanocomposite-based fluorescent probe was successfully applied to the quantitative detection of Cr3+ ion in milk sample (linear range = 2 to 10 nM) with better performance than other existing methods. Besides, this GO-RhB composite showed better antibiofilm activity against Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA) by using the Congo red agar and tube method. [ABSTRACT FROM AUTHOR]

Haploidentical transplantation can extend the opportunity for transplantation to almost all patients who lack an HLA-matched donor. Advances in the field of haploidentical transplantation have led to a marked decrease in treatment-related mortality, allowing investigators to focus on developing rationale pre- and peri-remission therapies aimed at preventing disease relapse after transplantation. Because of widespread availability, low treatment-related mortality, and cost, haploidentical donors may become the preferred alternative donors for allogeneic hematopoietic stem cell transplantation. One of the major advantages of using a related donor is the possibility of collecting or generating additional cellular products from the same immediately available donor, which will not be rejected. Infusion of these cells in the peri-transplantation period, derived from the same immune system, is opening the possibility of markedly enhancing the antitumor effects of the graft and hastening immunologic reconstitution after transplantation.

PurposePrevious studies show that inhibition of ABCB1 expression overcomes acquired docetaxel resistance in C4-2B-TaxR cells. In this study, we examined whether antiandrogens, such as bicalutamide and enzalutamide, could inhibit ABCB1 activity and overcome resistance to docetaxel.Experimental designABCB1 efflux activity was determined using a rhodamine efflux assay. ABCB1 ATPase activity was determined by Pgp-Glo assay systems. The effects of the antiandrogens bicalutamide and enzalutamide on docetaxel sensitivity were determined by cell growth assays and tumor growth in vivo.ResultsWe found that bicalutamide and enzalutamide inhibit ABCB1 ATP-binding cassette transporter activity through blocking ABCB1 efflux activity. Bicalutamide inhibited ABCB1 efflux activity by 40%, whereas enzalutamide inhibited ABCB1 efflux activity by approximately 60%. Both bicalutamide and enzalutamide inhibit ABCB1 ATPase activity. In addition, bicalutamide and enzalutamide inhibit ABCB1 efflux activity and desensitize docetaxel-resistant and androgen receptor (AR)-negative DU145 cells. Combination of bicalutamide with docetaxel had a significant antitumor effect in both AR-positive and AR-negative docetaxel-resistant xenograft models, suggesting that bicalutamide desensitizes docetaxel-resistant cells to docetaxel treatment independent of AR status.ConclusionsWe identified a novel mechanism of action for antiandrogens such as bicalutamide and enzalutamide as inhibitors of ABCB1 efflux and ATPase activity. Bicalutamide and enzalutamide desensitize docetaxel-resistant prostate cancer cells to docetaxel treatment independent of AR status. These studies may lead to the development of combinational therapies with bicalutamide/enzalutamide and docetaxel as effective regimens to treat advanced prostate cancer independent of AR status, and possibly other types of cancer.

Fluorescence anisotropy imaging is a popular method to visualize changes in organization and conformation of biomolecules within cells and tissues. In such an experiment, depolarization effects resulting from differences in orientation, proximity and rotational mobility of fluorescently labeled molecules are probed with high spatial resolution. Fluorescence anisotropy is typically imaged using laser scanning and epifluorescence-based approaches. Unfortunately, those techniques are limited in either axial resolution, image acquisition speed, or by photobleaching. In the last decade, however, selective plane illumination microscopy has emerged as the preferred choice for three-dimensional time lapse imaging combining axial sectioning capability with fast, camera-based image acquisition, and minimal light exposure. We demonstrate how selective plane illumination microscopy can be utilized for three-dimensional fluorescence anisotropy imaging of live cells. We further examined the formation of focal adhesions by three-dimensional time lapse anisotropy imaging of CHO-K1 cells expressing an EGFP-paxillin fusion protein.

Sum-over-state (SOS) expressions to simulate absorption spectroscopy and resonance Raman (RR) scattering including Franck-Condon (FC) and Herzberg-Teller (HT) effects are described. Starting from the general SOS method, several simplified SOS formulae are derived. In particular, within the so-called independent mode displaced harmonic oscillator model, it is shown that including the vibronic structure in the absorption and RR spectra only requires the calculation of FC overlap integrals of the type (θg0|θev), where g, e, and v stand for the electronic ground state, excited state, and vibrational quantum number, respectively. Additionally, an approximation of the latter approach is introduced, referred as the simplified Fe method, in which the FC factors are neglected. This method is advantageous from the computational point of view and it is demonstrated that it reproduces the main characteristics of the more involved approaches. The merits and drawbacks of the different methods are discussed by applying them to the prototypical compound of Rhodamine 6G. Overall, this work intends to unravel and clarify some differences in the SOS theories of RR scattering. [ABSTRACT FROM AUTHOR]

Well-ordered opaline photonic crystals are grown by inward growing self-assembly method from Rhodamine B dye-doped polystyrene colloids. Subsequent to self-assembly, the crystals are infiltrated with gold nanoparticles of 40 nm diameter. Measurements of the stopband features and photoluminescence intensity from these crystals are supplemented by fluorescence decay time analysis. The fluorescence decay times from the dye-doped photonic crystals before and after the infiltration are dramatically different from each other. A lowered fluorescence decay time was observed for the case of gold infiltrated crystal along with an enhanced emission intensity. Double-exponential decay nature of the fluorescence from the dye-doped crystal gets converted into single-exponential decay upon the infiltration of gold nanoparticles due to the resonant radiative process resulting from the overlap of the surface plasmon resonance with the emission spectrum. The influence of localized surface plasmon due to gold nanoparticles on the increase in emission intensity and decrease in decay time of the emitters is established. [ABSTRACT FROM AUTHOR]

A two-step glancing angle deposition method is developed to fabricate hierarchical metal nanostructures for surface enhanced Raman scattering (SERS). Nanotip arrays, which consist of a thin layer of silver on nickel nanoneedles, are deposited on silicon substrates by this method. Rhodamine 6G (R6G) is used to demonstrate the sensitivity of SERS at the near attomolar level. The scaling of Raman intensity with the concentration of R6G is related to the Langmuir- Freundlich isotherm. [ABSTRACT FROM AUTHOR]

The distance-dependence of excitation energy transfer, e.g., being described by Förster theory (Förster resonance energy transfer (FRET)), allows the use of optical techniques for the direct observation of structural properties. Recently, this technique has been successfully applied in the gas phase. The detailed interpretation of the experimental FRET results, however, relies on the comparison with structural modeling. We therefore present a complete first-principles modeling approach that explores the gas-phase structure of chromophore-grafted peptides and achieves accurate predictions of FRET efficiencies. We apply the approach to amyloid-ß 12-28 fragments, known to be involved in amyloid plaque formation connected to Alzheimer's disease. We sample structures of the peptides that are grafted with 5-carboxyrhodamine 575 (Rh575) and QSY-7 chromophores by means of replicaexchange molecular dynamics simulations upon an Amber-type forcefield parametrization as a function of the charge state. The generated ensembles provide chromophore-distance and -orientation distributions which are used with the spectral parameters of the Rh575/QSY-7 chromophores to model FRET-efficiencies for the systems. The theoretical values agree with the experimental average "action"-FRET efficiencies and motivate to use the herein reported parametrization, sampling, and FRET-modeling technique in future studies on the structural properties and aggregation-behavior of related systems. [ABSTRACT FROM AUTHOR]

A pulsed field gradient spin-echo nuclear magnetic resonance (NMR) sequence with solvent suppression (PGSE-WATERGATE) was applied to accurately measure the diffusion coefficients of Rhodamine 6G (Rh6G) in low-concentration aqueous solutions. Three samples with Rh6G concentrations of CRh6G = 1,4.5, and 25 μM were investigated. The precise determination of the diffusion coefficients in this low-concentration range was made possible by using a cryogenically cooled NMR probe and by the effective solvent suppression of the PGSE-WATERGATE sequence. The present results bridge the gap between diffusion data measured by fluorescence correlation spectroscopy in the single molecule limit and diffusivities obtained by pulsed field gradient NMR (PFG-NMR) without solvent suppression at higher concentrations. To further extend the concentration range, the diffusion coefficient of Rh6G was also measured on a sample with CRh6G = 410 μM by PFG-NMR. The overall concentration dependence of the Rh6G diffusion at 25 °C is discussed in terms of dimerization of the Rh6G molecules. The concentration-dependent monomer/dimer proportion is deduced from the diffusion data. [ABSTRACT FROM AUTHOR]

Recently, multiscale three-dimensional (3D) structures consisting of micrometer-scale structure and nanometer-scale structure have received some attention from scientists in the field of surface-enhanced Raman scattering (SERS). In this work, micrometer-scale grating structure and nanometer-scale zinc oxide nano spikes (ZnO NSs) structure are successfully introduced into the SERS substrate with silver nanoparticles (Ag NPs) as the surface plasmon. The optimized particle-in-multiscale 3D substrate (PDMS/grating/ZnO NSs/Ag NPs) presents high sensitivity with an ultralow limit of detection of 1 × 10−11 M and a high enhancement factor of 7.0 × 108 for Rhodamine 6G (R6G) as the probe molecule. It benefits from the electromagnetic field enhancement from the excellent optical capture capability of grating/ZnO NSs structure and abundant electromagnetic hot spots. The quantitative analysis ability of the SERS substrate can be indicated from the good linear correlation between the logarithmic Raman intensity and the molecular concentration. At the same time, this SERS substrate exhibits excellent homogeneity and reproducibility, which have low relative standard deviations (4.43%) of the Raman intensities at 613 cm−1 peaks for R6G as the probe molecule. In addition, this SERS substrate can realize in-situ detection of Raman signal due to its excellent light transmission and flexibility. The particle-in-multiscale 3D structure as SERS substrate exhibits the vast potential in practical applicability for qualitatively and quantitatively chemical and biomedical analysis. [ABSTRACT FROM AUTHOR]

The spiropyran derivatives can exist in two forms, the closed-ring spiropyran form and the open-ring merocyanine (MC) form. The SP form could be converted into the MC form upon UV irradiation. In this work, some 1′,3′,3′-trimethylspiro[chromene-2,2′-indoline] derivatives containing the nitro and formyl groups are synthesized via the reaction of 1,3,3-trimethyl-2-methylene-5-nitroindoline with the corresponding salicylaldehyde derivatives. These compounds have different photochromic behaviors. The synthesized photochromic molecules are characterized by the FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques. In order to investigate the photochromic properties of these compounds, the UV–visible spectroscopic analyses of their methanolic solutions before and after exposure to a UV lamp (in the spectral range of 360–400 nm) are studied. [ABSTRACT FROM AUTHOR]

Modification of eudesmane-type lactones isoalantolactone and 4,15-epoxyisoalantolactone was carried out at the active methylene group. The reaction of isoalantolactone with hydrazoic acid, which was formed in situ from sodium azide and acetic acid in the presence of triethylamine in toluene or DMF, proceeds in a controllable manner and, depending on the nature of the solvent and reaction conditions, leads to (11R)-13-azido-11,13-dihydroisoalantolactone, the spirocyclic compound (11R)-aziridino[11,13]dihydroisoalantolactone, and the product of the selective opening of the aziridine ring with the azide anion (11S)-11-amino-13-azido-11,13-dihydroisoalantolactone. The reaction of 4,15-epoxyisoalantolactone with hydrazoic acid proceeds similarly to form the corresponding 13-azido-, (11R)-aziridino[11,13]-, or (11S)-11-amino-13-azido-4,15-epoxy-11,13-dihydroisoalantolactones. The regioselective synthesis of libraries of (11R)-13-(1H-1,2,3-triazolyl)-11,13-dihydroisoalantolactones and (11S)-11-amino-13-(1H-1,2,3-triazolyl)-11,13-dihydroisoalantolactones containing various aryl or hetaryl substituents at the C-4 position of the triazole ring was carried out by the CuAAC reaction of 13-azido-substituted 11,13-dihydroisoalantolactones with terminal acetylenes. [ABSTRACT FROM AUTHOR]

The synthesis of spirocyclic amide acetals (33–93 %) has been achieved through Ru(II)‐catalyzed condensations of N‐carbamate protected pyrrolidinones with metal carbenes derived from α‐diazo‐β‐ketoesters. Thanks to the mildness of the diazo decomposition conditions induced by a 1 : 1 combination of [CpRu(MeCN)3][BArF] and 1,10‐phenanthroline, the formation of the sensitive products is possible. Full characterization of this carbonyl‐ylide mediated process is provided by DFT calculations. [ABSTRACT FROM AUTHOR]

Selective identification of metal ions as well as their removal is possible when a sensing unit is anchored to a solid support. In this paper, functionalized mesoporous silica with a pendant rhodamine 6G moiety (R6FMS) has been obtained by successive grafting of an aldehyde derivative of bisphenol A followed by rhodamine 6G over a 3-aminopropyl anchored mesoporous silica framework. The materials have been characterized by powder X-ray diffraction, nitrogen sorption and electron microscopy studies, FT-IR and solid state MAS NMR spectral studies, and thermal analysis. In ethanol, the colorless silica material gives pink coloration in the presence of Al3+, Cr3+, Fe3+ and Cu2+ which is also clearly evident from the generation of an absorption peak at 525 nm. Upon excitation at 500 nm, the fluorescence intensity of the probe increases by 36-, 17-, 40- and 89-fold in the presence of Al3+, Cr3+, Fe3+ and Cu2+ ions, respectively. This suggests that R6FMS is a colorimetric and fluorescent chemosensor for these cations in ethanol. However, when the solvent is changed from ethanol to water, it becomes a selective chemosensor only for Cu2+ and Hg2+, by the generation of a pink color and strong fluorescence at ca. 550 nm, thereby discriminating the trivalent cations. Cations induce the opening of the spirolactam ring resulting in pink coloration and strong fluorescence. The quantum yield and lifetime of the probe have been increased considerably in the presence of these cations in ethanol as well as in aqueous media. The detection limit values for these cations range from 10−6 to 10−8 M. R6FMS has been used to remove Hg2+ and Cu2+ from their aqueous solution with a maximum adsorption capacity of 35 mg g−1 and 148 mg g−1 for Cu2+ and Hg2+, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a turn-on fluorescent probe (DBE) was designed and synthesized for probing bisulfite (HSO3−) by coupling dehydroabietic acid-based benzimidazole derivatives with ethyl cyanoacetate moiety. The structure of the compound was characterized using its UV-Vis, 1H-NMR, 13C-NMR and HRMS spectra. The probe showed significant selectivity and sensitivity towards HSO3− compared to other analytes in DMF/PBS buffer (3/7, v/v, 10 mM, pH = 7.4), and exhibited a detection limit at the nanomolar level (3.2 nM), fast response time (140 s) and good pH stability (6–10) in living systems. Furthermore, this probe was successfully utilized for the fluorescence imaging of HSO3− in living zebrafish and MCF-7 cells with remarkable lysosome-targeting properties. [ABSTRACT FROM AUTHOR]