Synthesis, Crystal Structure, DFT and Fluorescence Quenching Study of Novel syringe aldehyde-derived hydrazinyl-imidazole Based Schiff base Chemosensor.

In this study, we report a new syringe aldehyde-derived hydrazinyl-imidazole based fluorescent sensor (L) for sensitive detection of different inorganic quenchers (halide ions, bicarbonate ion, sulphide ion and transition metal ions). The chromophore (L) was obtained in good yield by the 1:1 condensation reaction of 2-hydrazino-4,5-dihydroimidazole hydrobromide and 4-hydroxy-3,5-dimethoxy benzaldehyde. L exhibited strong fluorescence in the visible region (around 380 nm) and its interaction with different quenchers was studied in details via fluorescence technique. For the halide ions series, its sensitivity is higher for NaF (Climit = 4 × 10- 4 M) than for NaCl while the fluorescence quenching occurred mainly through a dynamic process. Similar considerations were observed for HCO3- and S2- quencher too, when static and dynamic quenching take place simultaneously. Regarding transition metal ions, at a fixed ion concentration (4 × 10- 6 M), best performance was achieved for Cu2+ and Fe2+ (fluorescence intensity was reduced by 79% and 84.9% respectively), while for other metal ions, the sensor performance was evaluated and found to be very less (< 40%). Thus, minimum detection limits (10- 6 - 10- 5 M range) recommended the use of such derivatives as highly sensitive sensors capable to monitor delicate changes in varied environments.

The relationship between changes in IL-2 / IL-18 and liver enzyme with dengue severity.

A synergistic impact of virulence capacity of dengue viruses and host immune response contributes to the pathogenesis of dengue virus infection (DENV). Elevation of hepatic enzyme and cytokine storm is the major contributory factor producing severity. IL-2 and IL-18 both play a critical role in generating immunogenicity during viral infection. The goal of the study was to evaluate the correlation between alterations in IL-2 and IL-18 levels with alterations in hepatic enzymes in dengue-infected patients. Accordingly, a total of 91 NS1/IgM confirmed DENV infected patients were selected for the IL-2 and IL-18 evaluation using a standard ELISA assay. Biochemical, haematological parameters were recorded at the time of admission. Interestingly, raised levels of IL-2 (p < 0.0001) and IL-18 (p < 0.0001) was obtained in severe dengue as compared to non-severe dengue patients. A significant positive correlation was observed between IL and 2 levels and SGOT (r = 0.3168 with p = 0.002), SGPT (r = 0.569 with p < 0.0001). Similarly IL-18 was also highly associated with SGOT (r = 0.387 with p = 0.0002) and SGPT (r = 0.407 with p < 0.0001) in dengue infected patient.Our data reveal that a rising amount of IL-2 and IL-18 in initial stage of the disease could be predictors for developing severe form of dengue infection.

Smartphone coupled with paper-based chemical sensor for on-site determination of iron(III) in environmental and biological samples.

We report a smartphone-paper-based sensor impregnated with cetyltrimethylammonium bromide modified silver nanoparticles (AgNPs/CTAB) for determination of Fe3+ in water and blood plasma samples. The methodology for determination of Fe3+ is based on the change in signal intensity of AgNPs/CTAB fabricated on a paper substrate after the deposition of analyte, using a smartphone followed by processing with ImageJ software. The mechanism of sensing for detection and determination of Fe3+ is based on the discoloration of AgNPs which impregnated the paper substrate. The discoloration is attributed to the electron transfer reaction taking place on the surface of NPs in the presence of CTAB. Fe3+ was determined when the paper was impregnated with 1 mM AgNPs for 5 min of reaction time and the substrate was kept under acidic conditions. The linear range for determination of total iron in terms of Fe3+ was 50-900 µg L-1 with a limit of determination (LOD) of 20 µg L-1 and coefficient of variation (CV) of 3.2%. The good relative recovery of 91.3-95.0% and interference studies showed the selectivity of the method for determination of total iron in water and blood plasma samples. Smartphone-paper-based sensors have advantages of simplicity, rapidity, user-friendliness, low cost, and miniaturization of the method for on-site determination of total iron compared to methods that require sophisticated analytical instruments. Graphical abstract Smartphone-paper-based sensor with cetyltrimethylammonium bromide modified silver nanoparticles for determination of Fe3+ in water and blood plasma samples.

Study of serum VEGF levels in patients with severe dengue infection admitted in a tertiary care hospital in Kolkata.

Dengue is the most common arboviral infection globally, but its pathogenesis is poorly explored. Vascular endothelial growth factor (VEGF) has an essential role in the host defense against viral infection. However, not much information is available regarding its status in dengue patients from the eastern zone of India. In the present investigation, the level of VEGF was investigated for its possible utility as a dengue severity marker. Accordingly, confirmed dengue cases were enrolled during 2016-2018. Serum from all the study subjects was subjected to the standard enzyme-linked immunosorbent assay test for VEGF analysis. In addition, we assessed the association of VEGF to dengue severity. The study revealed that VEGF titers (P < .0001) were significantly increased in severe dengue (SD) patients in contrast to those with a milder form of dengue. An association was obtained between VEGF and increased SGOT (r = 0.517 with P < .0001) while VEGF had a negative correlation with platelets in SD patients (r = -0.331 with P = .001). Enhanced VEGF titers along with decreased platelets had a good association with SD. The investigation revealed that high VEGF titers are novel indicators of dengue severity. However, our results must be verified in a study evaluating a larger number of dengue patients.

A dual-mode highly selective and sensitive Schiff base chemosensor for fluorescent colorimetric detection of Ni2+ and colorimetric detection of Cu2.

In this paper, a novel flexible Schiff base chemosensor N'-(2-hydroxy-3-methoxybenzylidene)-2-(benzamido)benzohydrazide (L) has been designed, synthesised and characterised by 1H-NMR, IR spectroscopy, ESI-MS spectrometry and single crystal XRD analysis. A significant fluorescence enhancement of L was observed only in the presence of Ni2+ ions with a detection limit of 3.64 µM whereas Cu2+ induced fluorescence quenching, although both the metals showed colorimetric responses in methanol-Tris-HCl buffer (10 mM, pH 7.2) solution (1 : 1, v/v). The single crystal structure of L-Cu2+ has also been determined. No major interference by the other effective background cations (Fe3+, Fe2+, Co2+, Zn2+, Cd2+, Hg2+, Pb2+, Cr3+, Ag+, Al3+ and Mn2+) was observed even at a higher concentration of analytes. The experimental results were further supported by DFT studies. The chemosensor L can be applied to the formation of binary logical devices, recovery of contaminated water samples and living intracellular media.

Status of circulating immune complexes, IL8 titers and cryoglobulins in patients with dengue infection.

Dengue, a serious viral infection caused by the mosquito vector, Aedes aegyptii, affects about 390 million people annually from more than 125 countries across the globe. However, until now, there is no reliable clinical or laboratory indicator to accurately predict the development of dengue severity. Here, we explored critical pathophysiological determinants like IL8, circulating immune complex (CIC) and cryoglobulin in dengue-infected patients for identification of novel dengue severity biomarker(s). Totally, 100 clinically suspected dengue cases were tested by NS1 ELISA and MAC ELISA for dengue virus aetiology. For control, 49 healthy volunteers were included. Blood profiling (complete hemogram and liver function test) of patient population were done using automated cell counter and standard auto analyzer based biochemical analysis. Serum CIC was quantified by PEG precipitation. Serum cryoglobulins were estimated by Folin assay. Levels of serum IL-8 were assessed by standard sandwich ELISA kits. Patient CIC were further characterized by SDS Gel electrophoresis. Forty per cent of the cases tested positive, of which 11 patients had severe clinical manifestation. The mean ±SEM of cryoglobulin concentration for DHF, DF, and HC were 1.30 ± 0.31, 0.59 ± 0.08 and 0.143 ± 0.009 µg/µl, respectively. Thus, DHF and DF patients have shown 9- and 2.2-fold increase in cryoglobulin levels; and 18- and 5-fold increased CIC, respectively compared to HC patients. The mean ±SEM of CIC-PEG index for DHF, DF and HC were 491 ± 41.22, 146 ± 14.19 and 27.98 ± 2.56, respectively. Raised levels of IL8 titers were also found in all 11 DHF patients. Peak levels of CIC, cryoglobulin and IL8 titers were associated with thrombocytopenia. SDS PAGE analysis of CIC from DHF revealed the presence of at least six protein bands that were not observed in samples from DF and HC. Prediction efficacy of IL8, CIC and cryoglobulin for DHF was determined using the receiver operator characteristic curve (ROC). The area under the curve was 1.00 for IL8, 0.99 for CIC and 0.74 for cryoglobulins. Overall, the results suggest that CIC, IL-8 and cryoglobulins may serve as important laboratory parameters to monitor dengue infection progression.

A highly sensitive triazole-based perfectly water soluble novel bis-Schiff base reversible fluorescent-colorimetric chemosensor for fast detection of Pb2+ ions.

A reversible fluorescent-colorimetric azino bis-Schiff base receptor for the detection of Pb2+ in aqueous medium has been developed for the first time. Receptor L exhibits an excellent selective and rapid fluorescent-colorimetric response towards Pb2+. The sensitivity of the fluorescent-based assay (0.53 nM) and colorimetric assay (1.0 nM) for Pb2+ is sufficiently good in comparison to previously reported literature. From 1H NMR data, Job plot measurement and the ESI-MS spectrum, a 1 : 2 stoichiometric complexation between L and Pb2+ has been established. Receptor L shows a remarkable detection ability in a wide pH range of 4-8 and it has been successfully utilised in the determination of Pb2+ in aqueous solution of bovine serum albumin protein and in real samples. The geometry of L has been optimized by both DFT studies and NMR, FTIR and mass spectra. Moreover, we have studied molecular docking of the probe L.

Correction: A highly sensitive triazole-based perfectly water soluble novel bis-Schiff base reversible fluorescent-colorimetric chemosensor for fast detection of Pb2+ ions.

[This corrects the article DOI: 10.1039/D3RA06185J.].

Organelle-targeting ratiometric fluorescent probes: design principles, detection mechanisms, bio-applications, and challenges.

Biological species, including reactive oxygen species (ROS), reactive sulfur species (RSS), reactive nitrogen species (RNS), F-, Pd2+, Cu2+, Hg2+, and others, are crucial for the healthy functioning of cells in living organisms. However, their aberrant concentration can result in various serious diseases. Therefore, it is essential to monitor biological species in cellular organelles such as the cell membrane, mitochondria, lysosome, endoplasmic reticulum, Golgi apparatus, and nucleus. Among various fluorescent probes for species detection within the organelles, ratiometric fluorescent probes have drawn special attention as a potential way to get beyond the drawbacks of intensity-based probes. This method depends on measuring the intensity change of two emission bands (caused by an analyte), which produces an efficient internal referencing that increases the detection's sensitivity. This review article discusses the literature publications (from 2015 to 2022) on organelle-targeting ratiometric fluorescent probes, the general strategies, the detecting mechanisms, the broad scope, and the challenges currently faced by fluorescent probes.

A quinazolin-based Schiff-base chemosensor for colorimetric detection of Ni2+ and Zn2+ ions and 'turn-on' fluorometric detection of Zn2+ ion.

Herein, we have reported a novel quinazolin-based Schiff base chemosensor (E)-2-benzamido-N'-(1-(pyridin-2-yl)ethylidene)benzohydrazide (L). L has been designed, synthesised and characterised by 1H-NMR, IR spectroscopy, ESI-MS spectrometry and theoretical studies. The receptor showed appreciable colorimetric λ max shift for both Ni2+ and Zn2+ ions and fluorometric "turn on" response in presence of only Zn2+ ion. The Jobs plot analysis revealed that receptor forms 2 : 1 complex with both the ions Ni2+ and Zn2+, further confirmed by ESI-MS analysis. The single crystal structure of L-Ni2+ complex (1) has also been determined. The colorimetric detection limits were calculated to 7.9 nM and 7.5 nM respectively for Ni2+ and Zn2+ in methanol-Tris-HCl buffer medium (10 mM, pH 7.2, 1 : 1 v/v). The chemosensor L can be applied for the recovery of contaminated water samples.

catena-Poly[[(triphenyl-phosphane)copper(I)]-di-µ-iodido-[(triphenyl-phosphane)copper(I)]-µ-{1,2-bis-[1-(pyridin-4-yl)ethyl-idene]hydrazine}].

In the title coordination polymer, [Cu(2)I(2)(C(14)H(14)N(4))(C(18)H(15)P)(2)](n), the Cu(I) atom is coordinated by two I atoms, one P atom and one N atom in a fairly regular tetra-hedral arrangement. A crystallographic inversion centre generates a Cu(2)I(2) diamond with a Cu-Cu separation of 3.0120 (5) Å. The complete N,N'-(1-pyridin-4-yl-ethethyl-idene)-hydrazine mol-ecule is also generated by inversion symmetry, and this bridging ligand leads to [011] polymeric chains in the crystal structure.

Increased levels of pentraxins protein and cytokines bear good association in patients with severe dengue infection.

Dengue is an arboviral infection with high rates of morbidity and mortality throughout the tropics and sub-tropics. This work studied the status of pentraxin (CRP/SAP) protein, ferritin, TNF-α and IL-1ß levels in Dengue patients of different pathophysiological manifestations. Accordingly, clinically confirmed Dengue cases (n = 97) were enrolled and subsequently blood parameters were studied by Haematology cell counter and Biochemistry Autoanalyser. CRP, SAP, ferritin, TNF-α and IL-1ß ELISA were done in all the samples by using standard ELISA kits. Statistical Analysis was done in all the experiments. The levels of CRP (p < 0.0001), SAP (p < 0.0001), ferritin (p < 0.0001), TNF-α (p < 0.0001) and IL-1ß (p < 0.0001) were high in patients with Severe Dengue as compared to Dengue without warning signs. High levels of SGOT, SGPT and decreased platelet counts were found in severe patients as compared to Healthy donor. CRP/SAP as well as TNF-α/IL-1ß were independently associated with both dengue severity and overall disease manifestation. Statistically significant increased CRP, SAP, ferritin, TNF-α and IL-1ß titres were correlated in patients with severe clinical manifestations as compared to mild disease forms of dengue. Elevated levels of pentraxin, TNF-α/IL-1ß in blood during dengue infection could act as an early predictor in Severe Dengue infection.

Clinical Proteomics Profiling for Biomarker Identification Among Patients Suffering With Indian Post Kala Azar Dermal Leishmaniasis.

Background: Post Kala Azar Dermal Leishmaniasis (PKDL) is a non-fatal dermal sequel of Visceral Leishmaniasis (VL), affecting individuals worldwide. Available diagnostic tools lack sensitivity and specificity toward identifying macular (MAC) PKDL patients, due to low parasite load in patients' sample. Confirmatory test like punch biopsy are invasive and painful. Considering the rural nature of this disease and the prevailing situation of diagnostic scenario, PKDL patients mostly remains unattended from receiving proper medical care. They in turn act as "mobile parasite reservoir," responsible for VL transmission among healthy individuals (HI). This study aims to identify PKDL disease specific glycated protein biomarkers, utilizing the powerful LC-MS/MS technology, which is the tool of choice to efficiently identify and quantify disease specific protein biomarkers. These identified PKDL disease specific novel glycoproteins could be developed in future as immunochromatographic based assay for efficient case detection. Methodology: Previously our lab had identified importance of glycated (Circulating Immune Complexes) CICs, among PKDL patients. This study aims to further characterize disease specific glycated protein biomarkers, among MAC PKDL patients for both diagnostic and prognostic evaluation of the disease. LC-MS/MS based comparative spectral count analysis of MAC PKDL to polymorphic (POLY) PKDL, HI, and Cured (CR) individuals were performed. Proteins level alterations among all study groups were confirmed by Western blot and enzyme-linked immunosorbant Assay (ELISA). Results: Among MAC PKDL patients 43, 60, 90 proteins were altered compared to POLY PKDL, HI, and CR groups, respectively. Filtering for the most significant proteins, Plasminogen (PLG) and Vitronectin (VTN) were identified which promisingly identified MAC PKDL cases. Active surveillance results from endemic districts of West Bengal revealed drastic rise of MAC PKDL cases, alarming the urgency for field adaptive efficient biomarker. Conclusion: This current study aims to establish PLG and VTN as novel diagnostic and prognostic protein biomarker for MAC and POLY PKDL cases management.

A novel dihydro phenylquinazolinone-based two-in-one colourimetric chemosensor for nickel(ii), copper(ii) and its copper complex for the fluorescent colourimetric nanomolar detection of the cyanide anion.

Currently, considerable efforts have been devoted to the detection and quantification of hazardous multi-analytes using a single probe. Herein, we have developed a simple, environment-friendly colourimetric sensor for the sensitive, selective and rapid detection of Ni2+ and Cu2+ ions using a simple organic Schiff base ligand L in methanol-Tris-HCl buffer (1 : 1 v/v, 10 mM, pH = 7.2). The probe L exhibited a binding-induced colour change from colourless to yellow and fluorescence quenching in the presence of both Ni2+ and Cu2+ ions. The interactions between L and the respective metal ions were studied by Job's plot, electrospray ionisation-mass spectrometry (ESI-MS), Fourier-transform infrared spectroscopy (FT-IR), density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. The limit of detection (LOD) of L towards Ni2+ and Cu2+ was calculated to be 7.4 × 10-7 M and 4.9 × 10-7 M, respectively. Furthermore, the L-Cu2+ complex could be used as a new cascade fluorescent-colourimetric sensor to detect CN- ions with a very low level of detection (40 nM). Additionally, L could operate in a wide pH range, and thus was successfully applied for the detection and quantification of Ni2+ and Cu2+ in environmental samples, and for building OR- and IMPLICATION-type logic gates.

Octahedral monodithiolene complexes of iron: characterization of S,S'-coordinated dithiolate(1-) pi radical monoanions: a spectroscopic and density functional theoretical investigation.

The reaction of cis-[Fe(III)(cyclam)Cl(2)]Cl with 1 equiv of sodium N-diethyldithiocarbamate, toluene-3,4-dithiolate, and maleonitriledithiolate in methanol in the presence of triethylamine afforded the cations [Fe(III)(cyclam)(Et(2)dtc)](2+) (1), [Fe(III)(cyclam)(tdt)](+) (2), and [Fe(III)(cyclam)(mnt)](+) (3), which were isolated as triflate, hexafluorophosphate, and tetrafluoroborate salt, respectively, using sodium triflate, potassium hexafluorophosphate, or sodium tetrafluoroborate as the source for the counteranion. Complexes 1, 2, and 3 possess an S = (1)/(2) ground state (low-spin ferric d(5)). These salts were characterized by X-ray crystallography, UV-vis, Mössbauer, and electron paramagnetic resonance spectroscopies. Cyclic voltammetry revealed that 2 and 3 are reversibly one-electron-reduced, generating neutral 2(red) and 3(red), respectively, and one-electron-oxidized, generating dicationic 2(ox) and 3(ox), respectively. Fe and S K-edge X-ray absorption spectroscopy (XAS) revealed that 2 (S = (1)/(2)) and 2(ox) (S = 0) possess a low-spin ferric ion. Complexes 2 and 3 are S,S'-coordinated to a closed-shell dithiolate(2-) ligand, whereas 2(ox) and 3(ox) consist of a low-spin ferric ion antiferromagnetically coupled to a dithiolate(1-) pi radical ligand. They are singlet diradicals [Fe(III)(cyclam)(dithiolate(*))](2+). The analysis of the sulfur K pre-edge transitions reveals significant multiplet effects in the spectra of 2 and 2(ox), which provide rare experimental evidence for a singlet diradical description for 2(ox). Mössbauer spectroscopy on frozen solutions of 2(red) clearly show the presence of a high-spin ferrous ion (S = 2). The experimentally established electronic structures of the three members of the electron transfer series [Fe(cyclam)(dithiolate)](2+,+,0) have been verified by broken symmetry density functional theoretical calculations, which have been calibrated against the experiment by calculating XAS and Mössbauer spectra.

1,2-Diphenyl-2-[4-(4-pyridyl)benzyl-idene-hydrazono]ethan-1-one.

In the title compound, C(26)H(19)N(3)O, the dimethyl-ene hydrazine (-C=N-N=C-) unit is approximately planar, the torsion angle around the N-N bond being 162.2 (6)°. The phenyl and benzoyl-phenyl rings at one end of the hydrazine unit are aligned at angles of 9.5 (5) and 88.5 (4)°, respectively, with respect to the hydrazine unit, whereas the benzene ring at the other end is twisted by an angle of 14.4 (4)°. In the crystal structure, mol-ecules are linked into centrosymmetric dimers by inter-molecular C-H⋯O hydrogen bonds. The monoclinic crystal under investigation shows pseudo-merohedral twinning with twin fractions of 0.63 and 0.37.

N,N'-Bis(4-pyridylmethyl-ene)octane-1,8-diamine.

The complete molecule of the title compound, C(20)H(26)N(4), is generated by a crystallographic centre of inversion and the central eight-carbon chain adopts a fully extended conformation. In the crystal, the molecules pack in layers parallel to (010).

Benzil bis-(ketazine).

THE TITLE COMPOUND (SYSTEMATIC NAME: 1,1',2,2'-tetra-phenyl-2,2'-azinodiethanone), C(28)H(20)N(2)O(2), was obtained by the reaction of benzil monohydrazone with chromium(III) nitrate. The dibenzyl-idene hydrazine unit is nearly planar (r.m.s. deviation = 0.073 Å) and the two benzoyl units are oriented almost perpendicular to it [dihedral angle = 87.81 (2), 87.81 (2)°]. The mol-ecules are linked into chains along the c axis by C-H⋯O hydrogen bonds and the chains are cross-linked via C-H⋯π inter-actions involving the benzoyl phenyl rings.

Assessment of chemokine and cytokine signatures in patients with dengue infection: A hospital-based study in Kolkata, India.

Dengue fever is an acute viral infection transmitted by arthropods but may evolve to severe clinical manifestations. Descriptions of the role of circulating immune modulators such as cytokines or chemokines in dengue immunopathogenesis have largely relied on data from South-east Asia and America, while India is poorly represented. This study characterizes dengue cases from West Bengal, eastern India, with respect to clinical profile and pro-inflammatory and inflammatory cytokines. We evaluated the profile of both inflammatory and anti-inflammatory cytokines (IFNγ, IL6, IL10, IL12 and TGFß) and chemokines (IL8, CXCL9, CXCL10 and RANTES) in 100 hospitalized NS1/IgM confirmed Dengue patients during the epidemic in West Bengal during 2017. Additionally, all necessary blood investigations of the study subjects were performed. The patients mostly hailed from Kolkata, followed by Nadia, 24 Parganas (North and South), Murshidabad and Midnapore. The most common presentations apart from fever and bodyache were gastrointestinal symptoms. An elevated levels of cytokines IL6 and IL10 chemokine IL8 and CXCL10 along with decreased RANTES were found in the patients with Severe Dengue as compared to mild forms of dengue (p < 0.0001) during 3-6 days of infections. A significant association was obtained between most of cytokine and increased SGPT, haematocrit, albumin and decreased platelet count, whereas a negative correlation with the level of RANTES to haematocrit (r=-0.220 with p = 0.029) was found in severe dengue cases with altered liver function parameters. This is the first study demonstrating cytokine and chemokine association with dengue severity from the eastern part of India. Taken together, this study demonstrated that the altered expression levels of IL6, IL10, IL8, CXCL10 and RANTES had significant associations with dengue severity parameters.

A novel hydrazide-based selective and sensitive optical chemosensor for the detection of Ni2+ ions: applications in live cell imaging, molecular logic gates and smart phone-based analysis.

A novel flexible "N", "O"-rich hydrazide-based Schiff base chemoreceptor, 2-(benzamido)-N'-((pyridin-2-yl)methylene)benzohydrazide (L), was designed, synthesised and characterised via1H-NMR, IR spectroscopy, ESI-MS spectrometry and single-crystal XRD analysis. The receptor showed a colorimetric and fluorometric "turn on" response in the presence of only Ni2+ ions in methanol-Tris-HCl buffer medium (10 mM, pH 7.2, 1 : 1 v/v). The Job plot analysis revealed that the receptor forms a 2 : 1 complex with Ni2+ ions, which was further confirmed via the ESI-MS analysis. A single crystal of the L-Ni2+ complex (2) was also isolated. The detection limit was calculated to be 1.8 µM colorimetrically and 1.18 µM fluorometrically, which are much lower than those recommended as per the WHO guidelines for drinking water. The experimental results were further supported by DFT studies. The chemosensor L was applied for the recovery of contaminated water samples, building of molecular logic gate, smart phone-based analysis and live cell imaging.