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1.
Inorg Chem ; 63(6): 2919-2933, 2024 Feb 12.
Article in English | MEDLINE | ID: mdl-38297514

ABSTRACT

CuAs2O4 has been explored as a heterogeneous catalyst in the fields of photocatalysis, electrocatalysis, and solvent-free organic transformation reactions. The homogeneity has been successfully attained for the first time by designing a pH-assisted hydrothermal synthesis technique. Single-crystal X-ray diffraction studies reveal that no phase transition has been observed by lowering the temperature up to 103 K with no existence of satellite reflections. The crystal structure exhibits tetragonal symmetry with space group P42/mbc and consists of [CuO6] octahedra and [AsO3E] tetrahedra (E represents the stereochemically active lone pair). Structural investigation shows a cylindrical void inside the structure, which could lead to interesting physical and chemical properties. The photocatalytic dye degradation efficiency with methylene blue (MB) showed ∼100% degradation, though the degradation efficiency increased by 2-fold with the addition of 6% H2O2. The reusability of the catalyst up to the 10th cycle with ∼35% MB dye degradation has been established. It can exhibit HER activity with a low overpotential of 165 mV with respect to RHE to attain the current density of j = 10 mA cm-2. SEM and TEM revealed rod-shaped particles, which supported the large number of catalytic active sites. The structural consistency of the catalyst after photodegradation and HER studies is confirmed by the PXRD pattern. XPS confirms the oxidation state of Cu and As in the compound. The catalytic activity toward the Knoevenagel condensation reaction at moderate temperature under solvent-free condition is also studied. TG-DTA shows an endothermic minimum (Tmin) at 436 °C due to the mass loss of As2O3.

2.
Inorg Chem ; 63(5): 2709-2724, 2024 Feb 05.
Article in English | MEDLINE | ID: mdl-38253000

ABSTRACT

A potential adsorbent, Sb4O5Cl2@NbSe2 composite, was generated from the Sb4O5Cl2 photocatalyst and 5 wt % layered 2H-NbSe2 nanoparticles for the highly effective removal of Cr(VI) and Fe(III) ions and methyl orange (MO) from aqueous solution, and a comparison was drawn against the precursors. Sb4O5Cl2 crystallites and NbSe2 nanoparticles were synthesized hydrothermally, and the composite was prepared by the incipient wetness impregnation technique. The crystal structure of Sb4O5Cl2 was determined by single-crystal X-ray diffraction (SCXRD) data. Powder X-ray diffraction (PXRD) study revealed the 2H phase of NbSe2 nanoparticles. Field emission scanning electron microscopy (FESEM) analysis confirmed the formation of the spherical-shaped NbSe2 nanoparticles from rod-shaped bulk 2H-NbSe2. Morphological changes from the hexagonal to irregular prismatic shape were found upon the formation of the Sb4O5Cl2@NbSe2 composite compared to pure Sb4O5Cl2. Negative ζ-potential values indicated that electrostatic interactions were the predominant factor for the adsorption process. Sb4O5Cl2@NbSe2 provided removal efficiencies of 99% for MO in 6 h, 96.52% for Cr(VI) within 2.5 h, and 92.43% for Fe(III) within 4 h of 10 mg/L initial concentration. The maximum adsorption capacities of the composite for MO, Fe(III), and Cr(VI) were found to be 66.56, 131.48, and 122.30 mg/g, respectively, as calculated using the Langmuir isotherm equation.

3.
Physiol Mol Biol Plants ; 29(3): 393-407, 2023 Mar.
Article in English | MEDLINE | ID: mdl-37033763

ABSTRACT

Hot chilli ('Bhut Jolokia') (Capsicum chinense Jacq.) is the hottest chilli widely grown in the North-Eastern region of India for its high pungency. However, little information is available on its physiology, growth and developmental parameters including yield. Therefore, the present research was undertaken to study the physiological responses of Bhut Jolokia under elevated CO2 (eCO2) and temperature. Two germplasms from two different agro-climatic zones (Assam and Manipur) within the North-East region of India were collected based on the pungency. The present study explored the interactive effect of eCO2 [at 380, 550, 750 ppm (parts per million)] and temperature (at ambient, > 2 °C above ambient, and > 4 °C above ambient) on various physiological processes, and expression of some photosynthesis and capsaicin related genes in both the germplasms. Results revealed an increase (> 1-2 fold) in the net photosynthetic rate (Pn), carbohydrate content, and C: N ratio in 'Bhut Jolokia' under eCO2 and elevated temperature regimes compared to ambient conditions within the germplasms. Gene expression studies revealed an up-regulation of photosynthesis-related genes such as Cs RuBPC2 (Ribulose biphosphate carboxylase 2) and Cs SPS (Sucrose phosphate synthase) which, explained the higher Pn under eCO2 and temperature conditions. Both the germplasm showed better performance under CTGT-II (Carbon dioxide Temperature Gradient Tunnel having 550 ppm CO2 and temperature of 2 °C above ambient) in terms of various physiological parameters and up-regulation of key photosynthesis-related genes. An up-regulation of the Cs  capsaicin synthase gene was also evident in the study, which could be due to the metabolite readjustment in 'Bhut Jolokia'. In addition, the cultivar from Manipur (cv. 1) had less fruit drop compared to the cultivar from Assam (cv. 2) in CTGT II. The data indicated that 550 ppm of eCO2 and temperature elevation of > 2 °C above the ambient with CTGT-II favored the growth and development of 'Bhut Jolokia'. Thus, results suggest that Bhut Jolokia grown under the elevation of CO2 up to 550 ppm and temperature above 2 °C than ambient may support the growth, development, and yield. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01294-9.

4.
Inorg Chem ; 62(2): 1032-1046, 2023 Jan 16.
Article in English | MEDLINE | ID: mdl-36598860

ABSTRACT

Zn3Sb4O6F6 crystallites were synthesized by a pH-regulated hydrothermal synthetic approach, while doping on Zn3Sb4O6F6 by KI was performed by the "incipient wetness impregnation technique." The effect of KI in Zn3Sb4O6F6 is found with the changes in morphology in the doped compound, i.e., needle-shaped particles with respect to the irregular cuboid and granular shaped in the pure compound. Closer inspection of the powder diffraction pattern of doped compounds also reveals the shifting of Braggs' peaks toward a lower angle and the difference in cell parameters compared to the pure compound. Both metal oxyfluoride comprising lone pair elements and their doped compounds have been successfully applied as photocatalysts for methylene blue dye degradation. Knoevenagel condensation reactions were performed using Zn3Sb4O6F6 as the catalyst and confirmed 99% yield even at 60 °C temperature under solvent-free conditions. Both pure and KI-doped compounds were tested against several standard bacterial strains, i.e., Enterobacter sp., Escherichia coli, Staphylococcus sp., Salmonella sp., Bacillus sp., Proteous sp., Pseudomonas sp., and Klebsiella sp. by the "disk diffusion method" and their antimicrobial activities were confirmed.


Subject(s)
Disinfection , Escherichia coli , Zinc/pharmacology , Catalysis
5.
Phys Chem Chem Phys ; 24(35): 20941-20952, 2022 Sep 14.
Article in English | MEDLINE | ID: mdl-36053209

ABSTRACT

A new ratiometric fluorescent probe (E)-2-(benzo[d]thiazol-2-yl)-3-(8-methoxyquinolin-2-yl)acrylonitrile (HQCN) was synthesised by the perfect blending of quinoline and a 2-benzothiazoleacetonitrile unit. In a mixed aqueous solution, HQCN reacts with hydrazine (N2H4) to give a new product 2-(hydrazonomethyl)-8-methoxyquinoline along with the liberation of the 2-benzothiazoleacetonitrile moiety. In contrast, the reaction of hypochlorite ions (OCl-) with the probe gives 8-methoxyquinoline-2-carbaldehyde. In both cases, the chemodosimetric approaches of hydrazine and hypochlorite selectively occur at the olefinic carbon but give two different products with two different outputs, as observed from the fluorescence study exhibiting signals at 455 nm and 500 nm for hydrazine and hypochlorite, respectively. A UV-vis spectroscopy study also depicts a distinct change in the spectrum of HQCN in the presence of hydrazine and hypochlorite. The hydrazinolysis of HQCN exhibits a prominent chromogenic as well as ratiometric fluorescence change with a 165 nm left-shift in the fluorescence spectrum. Similarly, the probe in hand (HQCN) can selectively detect hypochlorite in a ratiometric manner with a shift of 120 nm, as observed from the fluorescence emission spectra. HQCN can detect hydrazine and OCl- as low as 2.25 × 10-8 M and 3.46 × 10-8 M, respectively, as evaluated from the fluorescence experiments again. The excited state behaviour of the probe HQCN and the chemodosimetric products with hydrazine and hypochlorite are studied by the nanosecond time-resolved fluorescence technique. Computational studies (DFT and TDDFT) with the probe and the hydrazine and hypochlorite products were also performed. The observations made in the fluorescence imaging studies with human blood cells manifest that HQCN can be employed to monitor hydrazine and OCl- in human peripheral blood mononuclear cells (PBMCs). It is indeed a rare case that the single probe HQCN is found to be successfully able to detect hydrazine and hypochlorite in PBMCs, with two different outputs.


Subject(s)
Hypochlorous Acid , Leukocytes, Mononuclear , Fluorescent Dyes/chemistry , Humans , Hydrazines , Hypochlorous Acid/chemistry , Spectrometry, Fluorescence
6.
Dalton Trans ; 51(28): 10779-10786, 2022 Jul 19.
Article in English | MEDLINE | ID: mdl-35611756

ABSTRACT

Detection of biological phosphate is very important for environmental and health care applications. In this study, a new ratiometric fluorescent probe (E)-N'-(3-(benzo[d]thiazol-2-yl)-2-hydroxybenzylidene) picolinohydrazide (BTP) is developed and exhibits a prominent excited-state intramolecular proton-transfer (ESIPT) mechanism. The probe BTP undergoes a unique phosphate induced hydrolytic reaction in mixed aqueous solution which produces a colorimetric change associated with a huge red-shift of ∼130 nm in the UV-visible absorption spectrum. Initially, BTP exhibits a strong fluorescence emission as the ESIPT process is 'on' and the tautomeric hydrogen remains flexible and is free to give two tautomeric forms. Eventually, after the addition of PO43-, the two tautomeric forms break and thereby shift the equilibrium towards the 'enol' form. The phosphate ion binds with BTP which is associated with a ratiometric change and accounts for an enhancement in the fluorescence intensity with a large blue shift and the limit of detection value of 8.33 × 10-8 M in a mixed aqueous medium. The binding constant (1.92 × 105 M-1) proportionally reflects the stability of the complexation between the binding sites of BTP with the guest PO43- anion. The probable mechanism is supported by the NMR spectroscopy studies. The sensing phenomenon is found to be reversible towards Zn2+ and thus the sensor beautifully mimics the INHIBIT logic gate. Observations have been made in fluorescence imaging studies with human peripheral blood mononuclear cells (PBMCs) which indicates that BTP can be employed to successfully monitor the phosphate ion in human PBMCs.


Subject(s)
Leukocytes, Mononuclear , Protons , Fluorescent Dyes/chemistry , Humans , Phosphates , Spectrometry, Fluorescence/methods , Water/chemistry
7.
RSC Adv ; 12(14): 8374-8384, 2022 Mar 15.
Article in English | MEDLINE | ID: mdl-35424815

ABSTRACT

A pH-regulated hydrothermal synthesis method was employed to synthesize Sb4O5Br2 and Sb4O5Cl2 crystallites. Characterization is done by single crystal X-ray diffraction, powder X-ray diffraction, infra-red spectroscopy, scanning electron microscopy and DFT studies. The compounds crystallize in monoclinic symmetry with a P21/c space group. Complete structural analysis of the Sb4O5Br2 compound by using single crystal X-ray diffraction data is performed for the first time and a comparative study with Sb4O5Cl2 is also discussed. The SEM study reveals that the surface morphology changes with the variation of pH for bromide compounds, whereas pH change does not affect the morphology of the chloride analogues. Electronic band structures of the synthesized oxyhalides were investigated in order to understand their catalytic effects in the dye degradation reactions in dark as well as sunlight conditions.

8.
Article in English | MEDLINE | ID: mdl-35162212

ABSTRACT

Japan experienced natural hazards during the COVID-19 pandemic as some other countries did. Kumamoto and Kagoshima prefectures, including many other parts of southern Japan, experienced record-breaking heavy rain on 4th July 2020. While many countries were affected by compound hazards, some cases such as the Kumamoto flood did not cause a spike of the COVID-19 cases even after going through massive evacuation actions. This study aims to understand how COVID-19 made an impact on people's response actions, learn the challenges and problems during the response and recovery phases, and identify any innovative actions and efforts to overcome various restrictions and challenges through a questionnaire survey and interviews with the affected people. With an increase in the risk of compound hazards, it has become important to take a new, innovative, and non-traditional approach. Proper understanding and application of adaptive governance can make it possible to come up with a solution that can work directly on the complex challenges during disasters. This study identified that a spike of COVID-19 cases after the disaster could be avoided due to various preventive measures taken at the evacuation centers. It shows that it is possible to manage compound hazard risks with effective preparedness. Furthermore, during emergencies, public-private-partnership as well as collaboration among private organizations and local business networks are extremely important. These collaborations generate a new approach, mechanism and platform to tackle unprecedented challenges.


Subject(s)
COVID-19 , Disasters , Floods , COVID-19/epidemiology , Humans , Japan/epidemiology , Pandemics , SARS-CoV-2
9.
Comput Biol Med ; 126: 103990, 2020 11.
Article in English | MEDLINE | ID: mdl-32987200

ABSTRACT

This paper represents an unsupervised approach to detect the positions of S1, S2 heart sound events in a Phonocardiogram (PCG) recording. Insufficiency of correctly annotated heart sound database drives us to investigate unsupervised techniques. Gammatone filter bank features are used to characterize the spectral pattern of fundamental heart sound events from noise contaminated PCG data. An unsupervised spectral clustering technique is employed for segmentation of S1/S2 and non-S1/S2 heart sound events. A Feature winning score is computed to identify the S1/S2 and non-S1/S2 frames. Finally, time based threshold is applied to detect the accurate positions of S1 and S2 heart sounds. The performance of spectral clustering is compared with other clustering methods. The proposed method offers a maximum F1-score of 98% and 92.5% for normal and abnormal PCG data respectively on 2016 PhysioNet/CinC challenge dataset. The heart sound annotation algorithm provided by PhysioNet has been used as the ground truth after hand correction.


Subject(s)
Heart Sounds , Acoustics , Algorithms , Heart , Heart Auscultation , Phonocardiography , Signal Processing, Computer-Assisted
10.
J Glob Antimicrob Resist ; 17: 209-215, 2019 06.
Article in English | MEDLINE | ID: mdl-30634056

ABSTRACT

OBJECTIVES: The aim of this study was to identify and characterise probable extended-spectrum ß-lactamase (ESBL)-, AmpC lactamase- and/or metallo-ß-lactamase (MBL)-producing Escherichia coli variants circulating in the livestock and poultry environment to establish their epidemiological significance, genetic diversity, antimicrobial resistance (AMR) trends and virulence. METHODS: The culture method and E. coli-specific multiplex PCR identified 78 E. coli strains from faecal samples of healthy livestock and poultry. The antibiogram was determined by the disk diffusion and minimum inhibitory concentration (MIC) methods. Antimicrobial-resistant E. coli isolates were screened for the presence of ESBL, AmpC and MBL genes. Isolates were further characterised by plasmid replicon typing, integron assay and virulence gene analysis. Genetic diversity was assessed by random amplification of polymorphic DNA (RAPD) analysis and multilocus sequence typing (MLST). RESULTS: ESBL (CTX-M group 1, CTX-M group 4, TEM), AmpC (EBC, FOX, CMY, DHA) and MBL (IMP, SIM) resistance determinants were identified in 75%, 19% and 6% of isolates, respectively. Nine plasmid replicon types were distributed among resistant E. coli strains, with the most common plasmid replicon types being L/M and Y. Integrons were detected in 19% of E. coli isolates. RAPD analysis categorised the E. coli isolates into three clusters. MLST revealed seven different sequence types (STs), with ST10 being the most common. CONCLUSIONS: This study demonstrated a high prevalence of animals carrying potential ESBL- and AmpC-producing E. coli and emphasises the need for rigorous surveillance in the animal sector to identify critical control points conducive to prevent the rapid dissemination of AMR.


Subject(s)
Bacterial Proteins/genetics , Drug Resistance, Multiple, Bacterial/genetics , Escherichia coli/genetics , Livestock/microbiology , Molecular Epidemiology , Poultry/microbiology , beta-Lactamases/genetics , Animals , Anti-Bacterial Agents/pharmacology , Escherichia coli/drug effects , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Escherichia coli Infections/veterinary , Feces/microbiology , Genes, Bacterial/genetics , Genetic Variation , India , Microbial Sensitivity Tests , Multilocus Sequence Typing , Plasmids , Poultry Diseases , Random Amplified Polymorphic DNA Technique , Replicon , Virulence/genetics
11.
Genome Announc ; 6(17)2018 Apr 26.
Article in English | MEDLINE | ID: mdl-29700135

ABSTRACT

We report here the draft genome sequence of a multidrug-resistant Escherichia coli strain (NIVEDI-P44) isolated from a chicken fecal sample. The estimated genome size is 4.76 Mb, with a G+C content of 50.65%. The genome harbors multiple antibiotic resistance genes, blaDHA-1, mph(A), strA, strB, dfrA14, sul-2, tet(A), and qnrS1.

12.
J Med Eng Technol ; 41(3): 170-178, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28078906

ABSTRACT

This paper introduces a noise robust real time heart rate detection system from electrocardiogram (ECG) data. An online data acquisition system is developed to collect ECG signals from human subjects. Heart rate is detected using window-based autocorrelation peak localisation technique. A low-cost Arduino UNO board is used to implement the complete automated process. The performance of the system is compared with PC-based heart rate detection technique. Accuracy of the system is validated through simulated noisy ECG data with various levels of signal to noise ratio (SNR). The mean percentage error of detected heart rate is found to be 0.72% for the noisy database with five different noise levels.


Subject(s)
Electrocardiography/instrumentation , Electrocardiography/methods , Noise , Algorithms , Heart Rate/physiology , Humans , Internet , Signal Processing, Computer-Assisted
13.
Exp Parasitol ; 170: 168-176, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27702553

ABSTRACT

Aim of the present study was to assess the cytokine gene expression in liver, kidney and spleen and histopathological changes in mice infected with buffalo and dog isolates of Trypanosoma evansi. Forty-four Swiss albino mice was divided into eleven groups of four mice each and injected subcutaneously with 1 × 105 trypanosomes of buffalo and dog isolate to twenty mice each, four mice served as control. Mice were examined for clinical signs, blood smear for trypanosome counts. Blood for PCR, liver, kidney, spleen, heart, lung, testis and abdominal muscle for histopathology and liver, kidney, spleen for cytokine gene expression studies, were collected. Mice showed dullness, lethargy, hunched back, sluggish movements on D4 and D5 in buffalo and dog isolate, respectively. Parasite count in blood varied between the two isolates of T. evansi. By PCR, trypanosome DNA was detected on D1 and D2 for buffalo and dog isolate, respectively. Splenomegaly was observed in mice infected with buffalo isolate but not with dog isolate. Histopathological changes were observed in liver, kidney, spleen and heart of mice but no changes in testis and abdominal muscles. Blood vessels of liver, heart, lung showed presence of trypanosomes in mice infected with buffalo isolate but not for dog isolate. Cytokine gene expression of IL-2, IL-4, IL-6, IL-12, TNF-α and IFN-γ increased in liver, kidney and spleen in both these isolates. However, the buffalo isolate exhibited pronounced increase in cytokine gene expression when compare to dog isolate of T. evansi. Anti-inflammatory cytokine gene IL-10 showed 50-60 and 10-20 folds increment in buffalo and dog isolates, respectively. This is the first report of IL-4, IL-6, IL-10 and IL-12 cytokine changes in mice infected with T. evansi. A variation in pathogenicity between buffalo and dog isolates was recorded indicating buffalo isolate of T. evansi remained more pathogenic in mice.


Subject(s)
Cytokines/metabolism , Trypanosoma/immunology , Trypanosomiasis/immunology , Animals , Buffaloes , Cytokines/genetics , DNA, Protozoan/blood , DNA, Protozoan/isolation & purification , Dogs , Gene Expression , India , Kidney/immunology , Kidney/pathology , Liver/immunology , Liver/pathology , Lung/pathology , Male , Mice , Myocardium/pathology , Parasitemia/parasitology , RNA, Protozoan/analysis , RNA, Protozoan/isolation & purification , Real-Time Polymerase Chain Reaction , Spleen/immunology , Spleen/pathology , Trypanosoma/genetics , Trypanosomiasis/parasitology , Trypanosomiasis/pathology
14.
Clin Chim Acta ; 458: 144-53, 2016 Jul 01.
Article in English | MEDLINE | ID: mdl-27178483

ABSTRACT

BACKGROUND: Oxidative stress is common in type 2 diabetes. It is characterised by increased levels of reactive oxygen species (ROS), of which hypochlorous acid (HOCl) is an important component. Type 2 diabetes is characterised not only by hyperglycemia, but also by dyslipidemia. It probably underlies both the development of diabetes and also resulting complications, like cardiovascular disease. We applied a novel fluoroprobe RHQ to estimate endogenous HOCl and myeloperoxidase (MPO) activity in diabetes and dyslipidemia. METHODS: Our newly designed probe, RHQ (rhodamine-quinoline based chemodosimeter) is capable of estimating endogenous HOCl selectively out of the ROS components. Isolated leukocytes from study subjects were treated with DCFDA and monocytes and neutrophils with RHQ for estimating endogenous ROS and HOCl respectively. Plasma AOPP, an indicator of HOCl was also measured. We attempted to find out the key reasons of higher HOCl content in diabetic dyslipidemic subjects by quantitating endogenous hydrogen peroxide (H2O2) and myeloperoxidase (MPO) activity. RESULTS: Isolated PBMCs from diabetic dyslipidemic subjects indicated enhanced ROS and HOCl generation followed by diabetic subjects without dyslipidemia and healthy controls. We explored increased production of H2O2 and enhanced enzymatic activity of myeloperoxidase (MPO) among diabetic dyslipidemic subjects (p<0.0001) resulting in higher HOCl content. CONCLUSION: The hyperglycemic and hyperlipidemic challenges together enhance the production of HOCl and the fluoroprobe RHQ may be used as a novel diagnostic marker to evaluate the extent of this toxicity.


Subject(s)
Diabetes Mellitus, Type 2/metabolism , Dyslipidemias/metabolism , Fluorescent Dyes/analysis , Hypochlorous Acid/analysis , Quinolines/chemistry , Rhodamines/analysis , Fluorescent Dyes/chemistry , Humans , Hypochlorous Acid/metabolism , Hypochlorous Acid/poisoning , Reactive Oxygen Species/analysis , Reactive Oxygen Species/metabolism , Rhodamines/chemistry
15.
Inorg Chem ; 54(15): 7309-15, 2015 Aug 03.
Article in English | MEDLINE | ID: mdl-26192906

ABSTRACT

On the basis of the Förster resonance energy transfer mechanism between rhodamine and quinoline-benzothiazole conjugated dyad, a new colorimetric as well as fluorescence ratiometric probe was synthesized for the selective detection of Cd(2+). The complex formation of the probe with Cd(2+) was confirmed through Cd(2+)-bound single-crystal structure. Capability of the probe as imaging agent to detect the cellular uptake of Cd(2+) was demonstrated here using living RAW cells.


Subject(s)
Cadmium/analysis , Cadmium/chemistry , Fluorescence Resonance Energy Transfer/methods , Molecular Imaging/methods , Animals , Benzothiazoles/chemistry , Cell Survival , Crystallography, X-Ray , Mice , Quinolines/chemistry , RAW 264.7 Cells , Rhodamines/chemistry
16.
Dalton Trans ; 44(12): 5763-70, 2015 Mar 28.
Article in English | MEDLINE | ID: mdl-25714669

ABSTRACT

A new quinoline based sensor was developed and applied for the selective detection of Cd(2+) both in vitro and in vivo. The designed probe displays a straightforward approach for the selective detection of Cd(2+) with a prominent fluorescence enhancement along with a large red shift (∼38 nm), which may be because of the CHEF (chelation-enhanced fluorescence) and ICT (internal charge transfer) processes after interaction with Cd(2+). The interference from other biologically important competing metal ions, particularly Zn(2+), has not been observed. The visible-light excitability of the probe merits in the viewpoint of its biological application. The probe enables the detection of intracellular Cd(2+) with non-cytotoxic effects, which was demonstrated with the live RAW cells. The experimentally observed change in the structure and electronic properties of the sensor after the addition of Cd(2+) were modelled by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) computational calculations, respectively. Moreover, the test strip experiment with this sensor exhibits both absorption and fluorescence color changes when exposed to Cd(2+) in a mixed aqueous solution, which also makes the probe more useful. The minimum limit of detection of Cd(2+) by the probe was in the range of 9.9 × 10(-8) M level.


Subject(s)
Cadmium/analysis , Fluorescent Dyes/chemistry , Optical Imaging , Quinolines/chemistry , Cations, Divalent/analysis , Fluorescence , HCT116 Cells , Humans , Light , Spectrometry, Fluorescence , Water/analysis
17.
Chem Asian J ; 10(3): 694-700, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25605132

ABSTRACT

A new visible-light-excitable fluorescence ratiometric probe for OCl(-) has been developed based on a triphenylamine-diamiomaleonitrile (TAM) moiety. The structure of the dye was confirmed by single-crystal X-ray analysis. It behaves as a highly selective and sensitive probe for OCl(-) over other analytes with a fast response time (∼100 s). OCl(-) reacts with the probe leading to the formation of the corresponding aldehyde in a mixed-aqueous system. The detection limit of the probe is in the 10(-8) M range. The probe (TAM) also exhibits solvatofluorochromism. Changing the solvent from non-polar to polar, the emission band of TAM largely red-shifted. Moreover, the probe shows an excellent performance in real-life application in detecting OCl(-) in human blood cells. The experimentally observed changes in the structure and electronic properties of the probe after reaction with OCl(-) were studied by DFT and TDDFT computational calculations.


Subject(s)
Amines/chemistry , Erythrocytes/chemistry , Fluorescent Dyes/chemistry , Hypochlorous Acid/chemistry , Crystallography , Humans , Models, Molecular , Molecular Structure
18.
Chem Commun (Camb) ; 49(91): 10739-41, 2013 Nov 25.
Article in English | MEDLINE | ID: mdl-24104701

ABSTRACT

A spirobenzopyran-quinoline (SBPQ) based sensor was synthesized which selectively detects trivalent ions viz. Al(3+), Fe(3+) and Cr(3+) through a fluorescence turn on signal in the red region (~675 nm) with the detection limit in the order of 10(-8) M. The potentiality of the probe was confirmed by employing it for fluorescence bio-imaging with Al(3+) in three different types of live-cells.


Subject(s)
Aluminum/analysis , Cations/analysis , Chromium/analysis , Ferric Compounds/analysis , Benzopyrans/chemistry , Fluorescent Dyes , Quinolines/chemistry , Spectrometry, Fluorescence , Spectrophotometry, Ultraviolet , Spiro Compounds/chemistry
19.
Org Lett ; 15(21): 5412-5, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-24138076

ABSTRACT

A probe based on 2-(2'-hydroxyphenyl) benzothiazole (HBT) has been synthesized and used for the ratiometric detection of hydrazine. The probe is designed in such a way that the excited state intramolecular proton transfer (ESIPT) of the HBT moiety gets blocked. The chemodosimetric approach of hydrazine to the probe results in the recovery of the ESIPT by removal of a free HBT moiety through subsequent substitution, cyclization, and elimination processes. The probe is successfully demonstrated to enable the detection of hydrazine in live cells.


Subject(s)
Fluorescent Dyes/chemistry , Hydrazines/chemistry , Benzothiazoles/chemical synthesis , Benzothiazoles/chemistry , Cyclization , Molecular Imaging , Molecular Structure , Phenols/chemical synthesis , Phenols/chemistry , Protons , Spectrometry, Fluorescence
20.
Dalton Trans ; 42(42): 15113-9, 2013 Nov 14.
Article in English | MEDLINE | ID: mdl-24000084

ABSTRACT

A new fluorescent probe was synthesized from rhodamine-6G and 6-(hydroxymethyl) picolinohydrazide for the sensing of Fe(3+) in an aqueous environment. The structure of the sensor was confirmed through its single crystal X-ray study. It exhibits a high specificity and sensitivity towards Fe(3+) over other interfering heavy and transition metal ions (HTM). The turn-on greenish-yellow fluorescence and a colorimetric change from colourless to pink were observed upon addition of Fe(3+) which evokes almost 116- and 23-fold enhancement in absorbance and emission intensity respectively in an acetonitrile-water (1:1, v/v, 25 °C) solution at a neutral pH (pH = 7.2). The Fe(3+) promoted ring opening of the spirolactam framework to the open chain amide platform of the sensor is responsible for its visible colour change and turn-on fluorescence activity. It also exhibits an excellent performance in the "dip stick" method. Moreover the limit of detection of the probe is in the 10(-8) M range.


Subject(s)
Chelating Agents/chemistry , Fluorescent Dyes/chemistry , Iron/analysis , Rhodamines/chemistry , Ultraviolet Rays , Colorimetry , Fluorescent Dyes/chemical synthesis , Iron/chemistry , Limit of Detection , Models, Molecular , Molecular Structure , Quantum Theory
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