140 results on '"Sukhendu Nath"'
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2. Confining charge-transfer complex in a metal-organic framework for photocatalytic CO2 reduction in water
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Sanchita Karmakar, Soumitra Barman, Faruk Ahamed Rahimi, Darsi Rambabu, Sukhendu Nath, and Tapas Kumar Maji
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Science - Abstract
Abstract In the quest for renewable fuel production, the selective conversion of CO2 to CH4 under visible light in water is a leading-edge challenge considering the involvement of kinetically sluggish multiple elementary steps. Herein, 1-pyrenebutyric acid is post-synthetically grafted in a defect-engineered Zr-based metal organic framework by replacing exchangeable formate. Then, methyl viologen is incorporated in the confined space of post-modified MOF to achieve donor-acceptor complex, which acts as an antenna to harvest visible light, and regulates electron transfer to the catalytic center (Zr-oxo cluster) to enable visible-light-driven CO2 reduction reaction. The proximal presence of the charge transfer complex enhances charge transfer kinetics as realized from transient absorption spectroscopy, and the facile electron transfer helps to produce CH4 from CO2. The reported material produces 7.3 mmol g−1 of CH4 under light irradiation in aqueous medium using sacrificial agents. Mechanistic information gleans from electron paramagnetic resonance, in situ diffuse reflectance FT-IR and density functional theory calculation.
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- 2023
- Full Text
- View/download PDF
3. Charge-transfer regulated visible light driven photocatalytic H2 production and CO2 reduction in tetrathiafulvalene based coordination polymer gel
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Parul Verma, Ashish Singh, Faruk Ahamed Rahimi, Pallavi Sarkar, Sukhendu Nath, Swapan Kumar Pati, and Tapas Kumar Maji
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Science - Abstract
Designing active materials for efficient photocatalysis are of great interests. Herein the authors report coordination polymer gel assembled by low molecular weight gelator as photocatalysts for visible light driven H2 production and CO2 reduction regulated by charge-transfer interactions.
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- 2021
- Full Text
- View/download PDF
4. 2D-IR Spectroscopy of Nitrosyl Stretch of Sodium Nitroprusside Reveals the Elusive Two Anomalous Regions in the DMSO–Water Mixture
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Aruna K. Mora, Prabhat K. Singh, Rajasekhar Punna, and Sukhendu Nath
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Materials Chemistry ,Physical and Theoretical Chemistry ,Surfaces, Coatings and Films - Published
- 2023
5. Developing post-modified Ce-MOF as a photocatalyst: a detail mechanistic insight into CO2 reduction toward selective C2 product formation
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Sanchita Karmakar, Soumitra Barman, Faruk Ahamed Rahimi, Sandip Biswas, Sukhendu Nath, and Tapas Kumar Maji
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Nuclear Energy and Engineering ,Renewable Energy, Sustainability and the Environment ,Environmental Chemistry ,Pollution - Abstract
Post-synthetically modified defect-regulated Ce-UiO-66 MOF produces selective C2-based product (acetic acid) by visible light-driven CO2 reduction reaction.
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- 2023
6. Sensing lysozyme fibrils by salicylaldimine substituted BODIPY dyes - A correlation with molecular structure
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Ayentika Sen, Aruna K. Mora, Mrunesh Koli, Soumyaditya Mula, Soumitra Kundu, and Sukhendu Nath
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Boron Compounds ,Amyloid ,Molecular Structure ,Water ,General Medicine ,Biochemistry ,Structural Biology ,Molecular Probes ,Animals ,Female ,Muramidase ,Coloring Agents ,Chickens ,Molecular Biology ,Schiff Bases ,Boron ,Fluorescent Dyes - Abstract
Quick and efficient detection of protein fibrils has enormous impact on the diagnosis and treatment of amyloid related neurological diseases. Among several methods, fluorescence based techniques have garnered most importance in the detection of amyloid fibrils due to its high sensitivity and extreme simplicity. Among other classes of molecular probes, BODIPY derivatives have been employed extensively for the detection of amyloid fibrils. However, there are very few studies on the relationship between the molecular structure of BODIPY dyes and their amyloid sensing activity. Here in a BODIPY based salicylaldimine Schiff base and its corresponding boron complex have been evaluated for their ability to sense amyloid fibrils from hen-egg white lysozyme using steady state and time-resolved spectroscopic techniques. Both dyes show fluorescence enhancement as well as increase in their excited state lifetime upon their binding with lysozyme fibrils. However, the BODIPY derivative which shows more emission enhancement in fibrillar solution has much lower affinity towards amyloid fibrils as compared to other derivative. This contrasting behaviour in the emission enhancement and binding affinity has been explained on the basis of differences in their photophysical properties in water and amyloid fibril originating from the difference in their molecular structure. Such correlation between the amyloid sensitivity and the molecular structure of the probe can open up a new strategy for designing new efficient amyloid probes.
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- 2022
7. Confinement Matters: Stabilization of CdS Nanoparticles inside a Postmodified MOF toward Photocatalytic Hydrogen Evolution
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Adrija Ghosh, Sanchita Karmakar, Faruk Ahamed Rahimi, Raj Sekhar Roy, Sukhendu Nath, Ujjal K. Gautam, and Tapas Kumar Maji
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General Materials Science - Abstract
Insights into developing innovative routes for the stabilization of photogenerated charge-separated states by suppressing charge recombination in photocatalysts is a topic of immense importance. Herein, we report the synthesis of a metal-organic framework (MOF)-based composite where CdS nanoparticles (NPs) are confined inside the nanosized pores of Zr
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- 2022
8. An Isothiazolanthrone‐Based Self‐Assembling Anticancer Color‐Changing Dye for Concurrent Imaging and Monitoring of Cell Viability
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Nidhi Gour, Vivekshinh Kshtriya, Sajmina Khatun, Sujoy Bandyopadhyay, Rajib Ghosh, Bharti Koshti, Ramesh Singh, Ashadul Haque, Dhiraj Bhatia, Khashti Ballabh Joshi, Danil W. Boukhvalov, Sukhendu Nath, and Aravind K. Rengan
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Organic Chemistry ,General Chemistry ,Biochemistry - Published
- 2023
9. Unusual Growth and Hydration Characteristics of Oil Solubilized Micelles in Aqueous Pluronic Systems
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Sukhendu Nath, Vinod K. Aswal, M. Basu, Sugam Kumar, and Rajib Ganguly
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Aqueous solution ,Viscosity ,Chemistry ,Temperature ,technology, industry, and agriculture ,Water ,Viscometer ,Poloxamer ,macromolecular substances ,medicine.disease ,Micelle ,Surfaces, Coatings and Films ,law.invention ,Chemical engineering ,law ,Volume fraction ,Materials Chemistry ,Copolymer ,medicine ,Dehydration ,Physical and Theoretical Chemistry ,Micelles ,Essential oil - Abstract
Lipophile induced modulations of self-assembly characteristics in aqueous Pluronic systems merit attention because of wide-ranging uses of Pluronics as solubilizing agents of lipophilic substances. In this paper, we report unusual evolutions of structural and hydration properties in lavender essential oil (LO) solubilized Pluronic P85 aqueous micellar systems as a function of micellar volume fraction and temperature. Our DLS, SANS, and viscometry studies show that the spherical-to-wormlike micellar structural transition observed in 1% P85 solutions upon solubilization of LO quite unexpectedly gets suppressed with increased P85 concentration to ≥5%. Detailed SANS studies reveal that the core sizes of the oil solubilized micelles cannot attain the threshold value required for the onset of structural transition at higher copolymer concentrations due to their progressive shrinking with an increase in P85 concentration. Oil solubilized P85 solutions show two cloud points and very interestingly exhibit micellar growth upon cooling to their lower cloud points. Steady state fluorescence studies explain this based on increasing dehydration of micellar corona with a decrease in temperature, very much opposite to what is observed in pure aqueous Pluronic systems. The results give new insight into viscous flow properties and low temperature storage possibilities of oil solubilized aqueous Pluronic systems.
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- 2021
10. Natural DNA assisted white light generation and stimuli responsive colour tuning
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Rajib Ghosh, Bhupesh Kumar, Aruna K. Mora, and Sukhendu Nath
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Indoles ,Luminescence ,Time Factors ,Ultraviolet Rays ,Color ,Biochemistry ,Structure-Activity Relationship ,chemistry.chemical_compound ,Structural Biology ,Ethidium ,Molecule ,DAPI ,Emission spectrum ,Molecular Biology ,Fluorescent Dyes ,Anthracenes ,DNA ,General Medicine ,Chromophore ,Photochemical Processes ,Spectrometry, Fluorescence ,Energy Transfer ,chemistry ,Biophysics ,Nucleic acid ,Nucleic Acid Conformation ,Ethidium bromide ,Excitation - Abstract
The unique structure of a natural nucleic acid, calf thymus DNA, which can provide an appropriate scaffold for an efficient cascaded energy transfer among organic chromophores, has been used for the generation of bright and pure white light on UV light excitation. Two most commonly used DNA stains, 4′,6-diamidino-2-phenylindole (DAPI) and ethidium bromide (EB) have been used as a part of the donor-acceptor pairs. We have judiciously selected 10-anthracene-10-yl-3-methylbenzothiazol-3-ium chloride (AnMBTZ), an ultrafast molecular rotor, to act as a bridge between DNA bound DAPI and EB for the cascaded flow of energy. The unique molecular rotor properties of AnMBTZ and its exceptional binding ability with natural DNA help to form a distinct tri-chromophoric system in DNA template which can produce bright and pure white light on UV excitation. Detailed flow of energy from photoexcited DAPI to EB via AnMBTZ has been explored using steady state and time-resolved emission spectroscopy. Further, unique binding nature of AnMBTZ with DNA molecules has been used to modulate the colour of the emission from the present tri-chromophoric system by external stimuli, like salt and temperature. Such unique stimuli responsive multi-chromophoric system in a bio-template has great potential for different lightening applications.
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- 2021
11. Contrasting complexation behaviour of zwitterionic amyloid probe, SYPRO orange with β-cyclodextrin and captisol
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Aruna K. Mora, Payal Z. Hundani, and Sukhendu Nath
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General Chemical Engineering ,General Physics and Astronomy ,General Chemistry - Published
- 2023
12. Ultrafast isomerization vs bond twisting process – role of a proton
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Sukriti Santra, Aruna K. Mora, and Sukhendu Nath
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General Chemical Engineering ,General Physics and Astronomy ,General Chemistry - Published
- 2023
13. Dynamics of hydrogen bond reorganization in the S1(ππ*) state of 9-Anthracenecarboxaldehyde
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Rajib Ghosh, Sagnik Datta, Aruna K. Mora, Brindaban Modak, Sukhendu Nath, and Dipak K. Palit
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General Chemical Engineering ,General Physics and Astronomy ,General Chemistry - Published
- 2023
14. Surfactant mediated suppression of aggregation and excited state ring puckering process in Pyrromethene 597-Application in water based dye laser
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Ayentika, Sen, Aruna K, Mora, Sandeep K, Agarwalla, G, Sridhar, Soumitra, Kundu, and Sukhendu, Nath
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Surface-Active Agents ,Ethanol ,Porphobilinogen ,Solvents ,Lasers, Dye ,Water ,Instrumentation ,Spectroscopy ,Atomic and Molecular Physics, and Optics ,Fluorescent Dyes ,Analytical Chemistry - Abstract
Water is being considered as an economical, safe and environmental friendly alternative solvent for dye lasers. However, the use of water in dye laser is restricted due to the formation of non-emissive aggregates of dye molecules. In the present study we have explored the possibility of the use of commercially available surfactant molecules for the water based laser of Pyrromethene 597 (PM597) dye, which has emerged as an alternative for more commonly used Rhodamine dyes in dye laser systems. Our studies show that in water, PM597 forms non-emissive aggregates which can be dissociated into monomeric dye molecules by adding common surfactants. Further, the high microviscosity in the micellar media retarded energy wasting ring puckering process in the excited state of the dye leading to the increase in its emission yield and excited state lifetime to a significant extent. It has been demonstrated that the emission yield and excited state lifetime in surfactant solution is relatively higher than in ethanol, the most commonly used organic solvent for dye lasers. Lasing action has been demonstrated in the aqueous solution of dye and lasing efficiency is found to be comparable to ethanol.
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- 2022
15. Ultrafast Dynamics of a Molecular Rotor-Based Bioprobe-PicoGreen: Understanding toward Fibril Sensing Mechanism
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Aruna K. Mora and Sukhendu Nath
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Amyloid ,Polarity (physics) ,010402 general chemistry ,Fibril ,01 natural sciences ,Viscosity ,chemistry.chemical_compound ,0103 physical sciences ,Materials Chemistry ,Animals ,Insulin ,Organic Chemicals ,Physical and Theoretical Chemistry ,Cyanine ,Molecular Structure ,010304 chemical physics ,Chemistry ,0104 chemical sciences ,Surfaces, Coatings and Films ,Chemical physics ,Molecular Probes ,Intramolecular force ,Femtosecond ,Solvents ,Quantum Theory ,Polar ,Cattle - Abstract
A recent report shows that the cyanine-based molecular rotor, PicoGreen, has very strong affinity toward amyloid fibrils and shows large increase in its emission yield upon binding with insulin amyloid fibrils. To gain deeper knowledge about the excited-state molecular processes that are responsible for its amyloid sensing behavior, detailed ultrafast dynamics of PicoGreen in molecular solvents with varying polarity and viscosity have been investigated. Our detailed studies on femtosecond time-resolved emission of PicoGreen show that both polarity and viscosity of the medium a play vital role in the deactivation of its photoexcited state. Detailed analysis of the time-resolved data suggests the formation of the intramolecular charge transfer (ICT) state, which is independent of solvent viscosity, takes place in ultrafast time scales (2 ps), followed by the formation of a twisted ICT (TICT) state at a longer time scale in polar solvents. The formation of TICT from the ICT state due to the large amplitude torsional motion in its excited state has been supported by viscosity-dependent excited-state dynamics. Finally, the dynamical studies in fibrillar medium demonstrate the retardation in the excited-state torsional motion, which is primarily responsible for its observed large fluorescence enhancement in insulin amyloid fibrils.
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- 2019
16. Salt and phytochemical assisted modulation of self-assembly characteristics of Polysorbate-80 in aqueous medium
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Sukhendu Nath, Sugam Kumar, Rajib Ganguly, and Vinod K. Aswal
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Curcumin ,Alginates ,Phytochemicals ,Polysorbates ,Pharmaceutical Science ,Salt (chemistry) ,Lavender oil ,02 engineering and technology ,Sodium Chloride ,030226 pharmacology & pharmacy ,Micelle ,Polyvinyl alcohol ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Oils, Volatile ,Plant Oils ,Micelles ,chemistry.chemical_classification ,Aqueous solution ,Chemistry ,Vesicle ,Hydrogels ,021001 nanoscience & nanotechnology ,Lavandula ,Solubility ,Phytochemical ,Chemical engineering ,Micellar solutions ,Rheology ,0210 nano-technology - Abstract
Polysorbate 80 is one of the most widely used solubilizing agents in food, cosmetic and pharmaceutical industries. Influences of different classes of solubilizates and additives on its self-assembly characteristics are however, not sufficiently understood yet. In this manuscript, we show how common water structure making salt NaCl, and lipophilic phytochemicals like curcumin and lavender oil help in modulating the structure of Polysorbate 80 micelles in aqueous medium. Our DLS, SANS and rheological studies show that NaCl induces sphere-to-rod growth of polysorbate 80 micelles at the room temperature. Micellar solubilizations of the phytochemicals, which were found to be facilitated with increase in temperature, induce only a marginal growth of the micelles up to the highest level of solubilization. Their presence however, helps in modulating the NaCl induced micellar growth behavior in the tween 80 solutions leading to observation of micelle-to-vesicle structural transition at 2% lavender oil concentration. The phytochemical solubilized micellar solutions could be converted to alginate based hydrogel beads and patches that can freely release micellar phytochemical in aqueous medium. Our results shed light on possible ways of modulating the solubilization behavior, self-assembly characteristics and rheological properties of aqueous system of polysorbate 80, which could be important for their applications.
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- 2019
17. Role of solvent H-bonding and polarity on photophysical properties of a benzothiazole-based ratiometric amyloid fibril sensor
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Subrata Chattopadhyay, Aruna K. Mora, Sushant Murudkar, Alagarsamy Alamelu, and Sukhendu Nath
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Hydrogen bond ,General Chemical Engineering ,Solvatochromism ,General Physics and Astronomy ,02 engineering and technology ,General Chemistry ,Dihedral angle ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,Aniline ,chemistry ,Benzothiazole ,Molecule ,Steady state (chemistry) ,0210 nano-technology - Abstract
Detailed photophysical properties of 2-[2′-Me,4′-(dimethylamino)-phenyl]benzothiazole (2Me-DABT), a potential ratiometric amyloid fibril sensor, have been investigated in different solvents and solvent mixtures using steady state and time-resolved spectroscopic techniques. Our studies show that emission properties of 2Me-DABT are significantly modulated by polarity of solvent media. Extent of solvatochromism (3585 cm−1) shown by 2Me-DABT is quite large and can be used to monitor micropolarity of different complex media. Further, Stokes’ shift (>10,000 cm−1) shown by 2Me-DABT in all studied solvents is also much larger than most common molecular probes. It has also been shown that hydrogen bonding with solvent molecules results in large modulation in photophysical properties of 2Me-DABT. The H-bonding with water molecules induces a large change (39°) in the dihedral angle between benzothiazole and aniline moieties resulting large changes in photophysical properties of 2Me-DABT in polar protic solvents. Photophysical properties reported herein are used to explain observed amyloid sensing behaviour of 2Me-DABT. Detailed quantum chemical calculations are performed to support the experimental results.
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- 2019
18. Polymer-assisted drug sequestration from plasma protein by a surfactant with curtailed denaturing capacity
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Sukhendu Nath, Aruna K. Mora, Rahul Kalel, and Arghyadeep Basu
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Drug ,Protein Denaturation ,Polymers ,media_common.quotation_subject ,Supramolecular chemistry ,General Physics and Astronomy ,Poloxamer ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Pulmonary surfactant ,Nitriles ,Physical and Theoretical Chemistry ,Micelles ,media_common ,chemistry.chemical_classification ,Molecular Structure ,Chemistry ,Pulmonary Surfactants ,Serum Albumin, Bovine ,Polymer ,021001 nanoscience & nanotechnology ,Biocompatible material ,Blood proteins ,0104 chemical sciences ,Pluronic micelles ,Kinetics ,Spectrometry, Fluorescence ,Chemical engineering ,Critical micelle concentration ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions ,Quinolizines - Abstract
The capability of a surfactant to sequester a drug bound to plasma protein was investigated using steady-state and time-resolved spectroscopic techniques. Surfactants are known to denature protein, and hence are not suitable for the sequestration of a drug from protein. Herein, we show that the denaturing capacity of a surfactant is curtailed completely and its drug sequestration power is enhanced in the presence of biocompatible Pluronic micelles due to the formation of unique supramolecular assemblies. Further, our detailed studies indicate that the concentration of surfactant required for the sequestration of a drug is less than its critical micellar concentration (CMC). The extent of sequestration of drug by polymer-surfactant supramolecular assemblies can be tuned finely by controlling the concentration of surfactant. Detailed analysis showed that up to ∼85% sequestration of a drug from plasma protein could be achieved using a sub-CMC concentration of surfactant. Our results clearly show that controlled sequestration of a drug from plasma protein can be achieved with a reduction in the protein denaturing properties of surfactants.
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- 2019
19. Dynamics in tris(pentafluoroethyl)trifluorophosphate (FAP) anion based ionic liquids: A 2D-IR study with tungsten hexacarbonyl
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Aruna K. Mora, Prabhat K. Singh, and Sukhendu Nath
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Materials Chemistry ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Spectroscopy ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2022
20. Is DAPI assay of cellular nucleic acid reliable in the presence of protein aggregates?
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Aruna K. Mora, Birija S. Patro, Sukhendu Nath, and Sufiyan Khan
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Indoles ,Protein aggregation ,010402 general chemistry ,01 natural sciences ,Catalysis ,03 medical and health sciences ,chemistry.chemical_compound ,Protein Aggregates ,Cell Line, Tumor ,Materials Chemistry ,Humans ,DAPI ,030304 developmental biology ,Fluorescent Dyes ,0303 health sciences ,Amyloid beta-Peptides ,Metals and Alloys ,General Chemistry ,DNA, Neoplasm ,Branched DNA assay ,Fluorescence ,eye diseases ,Peptide Fragments ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Staining ,Spectrometry, Fluorescence ,Biochemistry ,chemistry ,Cell culture ,Ceramics and Composites ,Nucleic acid ,sense organs ,DNA - Abstract
DAPI is used extensively to identify and quantify DNA in cellular systems assuming its exclusive staining of nucleic acids. However, the present results show that DAPI has much higher affinity towards protein aggregates than DNA. Thus, the use of DAPI for the nucleic acid assay of cellular systems with protein aggregates may not be very reliable.
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- 2020
21. Charge-transfer regulated visible light driven photocatalytic H
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Parul, Verma, Ashish, Singh, Faruk Ahamed, Rahimi, Pallavi, Sarkar, Sukhendu, Nath, Swapan Kumar, Pati, and Tapas Kumar, Maji
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Energy ,Photocatalysis ,Gels and hydrogels ,Article - Abstract
The much-needed renewable alternatives to fossil fuel can be achieved efficiently and sustainably by converting solar energy to fuels via hydrogen generation from water or CO2 reduction. Herein, a soft processable metal-organic hybrid material is developed and studied for photocatalytic activity towards H2 production and CO2 reduction to CO and CH4 under visible light as well as direct sunlight irradiation. A tetrapodal low molecular weight gelator (LMWG) is synthesized by integrating tetrathiafulvalene (TTF) and terpyridine (TPY) derivatives through amide linkages and results in TPY-TTF LMWG. The TPY-TTF LMWG acts as a linker, and self-assembly of this gelator molecules with ZnII ions results in a coordination polymer gel (CPG); Zn-TPY-TTF. The Zn-TPY-TTF CPG shows high photocatalytic activity towards H2 production (530 μmol g−1h−1) and CO2 reduction to CO (438 μmol g−1h−1, selectivity > 99%) regulated by charge-transfer interactions. Furthermore, in situ stabilization of Pt nanoparticles on CPG (Pt@Zn-TPY-TTF) enhances H2 evolution (14727 μmol g−1h−1). Importantly, Pt@Zn-TPY-TTF CPG produces CH4 (292 μmol g−1h−1, selectivity > 97%) as CO2 reduction product instead of CO. The real-time CO2 reduction reaction is monitored by in situ DRIFT study, and the plausible mechanism is derived computationally., Designing active materials for efficient photocatalysis are of great interests. Herein the authors report coordination polymer gel assembled by low molecular weight gelator as photocatalysts for visible light driven H2 production and CO2 reduction regulated by charge-transfer interactions.
- Published
- 2020
22. SYPRO Orange - a new gold standard amyloid probe
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Sukhendu Nath and Aruna K. Mora
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Amyloid ,Biomedical Engineering ,macromolecular substances ,Orange (colour) ,010402 general chemistry ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,mental disorders ,General Materials Science ,Coloring Agents ,Reference standards ,030304 developmental biology ,0303 health sciences ,Chemistry ,Spectral properties ,General Chemistry ,General Medicine ,Merocyanine dye ,Carbocyanines ,Reference Standards ,Amyloid fibril ,0104 chemical sciences ,nervous system ,Biophysics ,Thioflavin ,Preclinical imaging - Abstract
SYPRO Orange, a zwitterionic merocyanine dye, can strongly interact with amyloid fibrils and shows enormous (∼1200 times) increase in its emission intensity. The sensitivity of the new probe is several times higher than that of the gold standard amyloid probe thioflavin T. Unlike thioflavin-T, the new probe has spectral properties suitable for in vivo imaging with detection sensitivity in the picomolar range.
- Published
- 2020
23. Monitoring the formation of insulin oligomers using a NIR emitting glucose-conjugated BODIPY dye
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Sukhendu Nath, Aruna K. Mora, Sushant Murudkar, Subrata Chattopadhyay, Soumyaditya Mula, and Neelam Shivran
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Boron Compounds ,Time Factors ,Infrared Rays ,macromolecular substances ,02 engineering and technology ,Conjugated system ,Fibril ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Protein Aggregates ,Structural Biology ,Animals ,Insulin ,Coloring Agents ,Molecular Biology ,Physiological stress ,030304 developmental biology ,0303 health sciences ,Protein molecules ,Near-infrared spectroscopy ,General Medicine ,021001 nanoscience & nanotechnology ,Fluorescence ,Kinetics ,Glucose ,Spectrometry, Fluorescence ,chemistry ,Biophysics ,Solvents ,Cattle ,BODIPY ,Protein Multimerization ,0210 nano-technology ,Chickens ,Preclinical imaging - Abstract
Protein oligomers, which are formed due to the aggregation of protein molecules under physiological stress, are neurotoxic and responsible for several neurological diseases. Early detection of protein oligomers is essential for the timely intervention in the associated diseases. Although several probes have been developed for the detection of insoluble matured protein fibrils, fluorescent probes with emission in the near infrared (NIR) region for probing protein oligomers are very rare. In the present study we have designed and synthesized a glucose-conjugated BODIPY dye with emission in the NIR spectral range. Our detailed studies show that the new probe is not only capable of detecting matured fibrils but can also probe the formation of oligomers from the native protein. The new probe shows a large increase in its emission intensity upon association with oligomers and matured fibrils. Hence, the present probe has a great potential for the in vivo imaging of protein oligomers and matured fibrils. Detailed spectroscopic properties of the new probes in molecular solvents have been performed to understand its oligomers- and fibril- sensing mechanism.
- Published
- 2020
24. Understanding the amyloid sensing mechanism of SYPRO Orange
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Aruna K. Mora and Sukhendu Nath
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Amyloid ,Chemistry ,Process Chemistry and Technology ,General Chemical Engineering ,Quantum yield ,02 engineering and technology ,Orange (colour) ,Merocyanine dye ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,Low emission ,mental disorders ,Solvent polarity ,Biophysics ,Thioflavin ,0210 nano-technology - Abstract
Amyloid fibrils, an aggregated form of proteins, are responsible for different types of neurological diseases. A constant effort is there for the search of a sensitive and selective probe for amyloid fibrils. Recently, it has been shown that a zwitterionic merocyanine dye, SYPRO Orange, can detect the amyloid fibrils with much higher sensitivity and with much preferred spectroscopic properties than present gold standard amyloid probe, Thioflavin T. In the present work, we have investigated the detailed photophysical properties of SYPRO Orange in different molecular solvents and solvent mixtures with wide range of properties to disentangle the fundamental processes that are responsible for its amyloid sensing activity. It has been shown that SYPRO Orange forms aggregates in water and results in extremely low emission quantum yield. The amyloid induced de-aggregation of SYPRO Orange is primarily responsible for enormous increase in its emission intensity upon binding with amyloid fibrils. Photophysical studies using steady state and time-resolved emission spectroscopy further enlighten us on the role of solvent polarity, solute-solvent H-bonding and solvent viscosity on its sensitivity towards amyloid fibrils. Thus, present results will be quite useful for the use of SYPRO Orange in different other spectroscopic applications.
- Published
- 2021
25. Synergistic enhancement in the drug sequestration power and reduction in the cytotoxicity of surfactants
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Dipak K. Palit, Aruna K. Mora, Sukhendu Nath, Birija S. Patro, and Rahul Kalel
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Polymers ,Supramolecular chemistry ,General Physics and Astronomy ,Poloxamer ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Micelle ,Surface-Active Agents ,chemistry.chemical_compound ,Pulmonary surfactant ,Organic chemistry ,Pharmacokinetics ,Physical and Theoretical Chemistry ,Solubility ,Sodium dodecyl sulfate ,Micelles ,chemistry.chemical_classification ,Chemistry ,Sodium Dodecyl Sulfate ,DNA ,Polymer ,021001 nanoscience & nanotechnology ,Intercalating Agents ,0104 chemical sciences ,Pharmaceutical Preparations ,Chemical engineering ,Critical micelle concentration ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions - Abstract
Surfactants have often been employed for the sequestration of drugs from DNA. However, for an effective sequestration, the concentration of the surfactant needs to be higher than its critical micellar concentration (CMC). Use of such high concentrations of the surfactant may limit its practical usage as a sequestering agent due to its cytotoxicity. In the present study we have shown that sodium dodecyl sulfate (SDS) itself at a concentration less than its CMC failed to sequester a drug from DNA. However, the sequestration power of SDS at sub-CMC concentration could be enhanced to a significant extent when incorporated into Pluronic polymer micelles in the form of supramolecular assemblies. Such a sequestration process was monitored through detailed photophysical properties of a model drug using steady-state and time-resolved fluorescence techniques. It has also been demonstrated that unlike a conventional surfactant, the sequestration of drugs by SDS-polymer supramolecular assemblies can be controlled by their compositions. Two Pluronic polymers with different compositions have been used to understand the effect of polymer composition on the sequestration process. It has been shown that with the increase in the length of the hydrophilic blocks of the polymer, the extent of sequestration decreases due to the decrease in the sequestering force exerted on the intercalated drug. Most importantly, our in vitro cell viability studies show that the toxicity of the SDS surfactant is reduced to a remarkable extent due to its incorporation into the polymer micelles.
- Published
- 2017
26. Anthryl Benzothiazolium Molecular Rotor-Based Turn-On DNA Probe: Detailed Mechanistic Studies
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Aruna K. Mora, Sukhendu Nath, Rajib Ghosh, and Bhupesh Kumar
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Fluorophore ,010402 general chemistry ,Photochemistry ,01 natural sciences ,chemistry.chemical_compound ,0103 physical sciences ,Materials Chemistry ,Molecule ,Benzothiazoles ,Physical and Theoretical Chemistry ,Density Functional Theory ,chemistry.chemical_classification ,Anthracenes ,Anthracene ,010304 chemical physics ,Molecular Structure ,Biomolecule ,Hybridization probe ,DNA ,Fluorescence ,0104 chemical sciences ,Surfaces, Coatings and Films ,chemistry ,Benzothiazole ,DNA Probes - Abstract
An efficient turn-on fluorescence probe for biomolecules not only helps in its sensitive detection but is also useful to understand the different interactions that are operating between biomolecules and probes. Polycyclic aromatic molecules are known to be strong interacting ligand for DNA and extensively studied as a model cancer drug. However, these molecules show large decrease in their emission intensity, i.e., a turn-off probe for DNA. In the present work, we have synthesized a benzothiazole-based anthracene derivative and studied its interaction with a natural DNA with the aim of having a turn-on DNA probe with a polycyclic aromatic moiety. Our detailed spectroscopic studies show that the new probe strongly interacts with DNA molecules and results in a significant increase in its emission yield. Time-resolved studies show a large increase in probe's excited-state lifetime in DNA solution. Detailed experiments have been performed to understand its mode of interaction with DNA molecules. The mode of interaction has also been supported by the blind molecular docking studies. Further, the viscosity-dependent photophysical properties and detailed quantum chemical calculations confirm that the new probe belongs to molecular rotor class of molecules. Association with DNA molecules results in a significant retardation in the nonradiative deactivation process due to the torsional motion in the excited state of the probe and leads to a significant increase in its emission yield. Thus, due its molecular rotor nature, despite with a turn-off fluorophore unit, anthracene, the new probe, acts as a sensitive turn-on fluorescence probe for DNA molecules.
- Published
- 2019
27. Disentangling Time Scales of Vibrational Cooling, Solvation, and Hydrogen Bond Reorganization Dynamics Using Ultrafast Transient Infrared Spectroscopy of Formylperylene
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Rajib Ghosh, Sukhendu Nath, and Aruna K. Mora
- Subjects
Materials science ,010304 chemical physics ,Hydrogen bond ,Dynamics (mechanics) ,Solvation ,Infrared spectroscopy ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Solvent ,Chemical physics ,0103 physical sciences ,Materials Chemistry ,Transient (oscillation) ,Physical and Theoretical Chemistry ,Ultrashort pulse - Abstract
Unraveling dynamics of solvation and hydrogen bond (H-bond) reorganization between a solute and solvent is crucial to understand the importance of specific and nonspecific interactions in a solution-phase chemical reaction. Ultrafast time-resolved infrared (TRIR) spectroscopy provides direct opportunity to monitor site-specific intermolecular dynamics on a real-time scale by probing vibrational marker bands in the excited state of a solute. Herein, we report the real-time dynamics of vibrational cooling, solvation, and hydrogen bond reorganization of formylperylene (FPe) through TRIR spectroscopy of carbonyl (C═O) stretching mode in nonpolar, polar aprotic, and polar protic solvents. High sensitivity of the C═O stretch frequency (υ̅
- Published
- 2019
28. How mobile is the water in the reverse micelles? A 2DIR study with an ultrasmall IR probe
- Author
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Aruna K. Mora, Sukhendu Nath, Shirish A. Nadkarni, and Prabhat K. Singh
- Subjects
Materials science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Micelle ,Ion ,chemistry.chemical_compound ,Materials Chemistry ,Molecule ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Spectroscopy ,Physics::Atmospheric and Oceanic Physics ,Hydrogen bond ,Relaxation (NMR) ,Radius ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,chemistry ,Chemical physics ,Azide ,0210 nano-technology - Abstract
Water molecules in reverse micelle serve as an excellent model for biological water. However, it has been argued previously that water molecules at the centre, even for smaller sized water pools of reverse micelles, behave like bulk water, using ultrafast vibrational lifetime measurements of azide ion. In the present investigation, the vibrational dynamics of an ultrasmall IR probe, azide ion, has been studied in AOT reverse micelle, at various w0 (radius of water pool), using linear IR measurements, vibrational lifetime measurements and 2D-IR measurements. While linear IR measurements show gradual variation in spectral parameters, such as, peak position and width of the vibrational transition, suggesting a gradual change in the micro environment of the probe with variation in radius of the water pool, the vibrational lifetime remains indistinguishable with variation in w0, which has been ascribed earlier to the location of azide ion in the centre of the water pool. Herein, ultrafast 2DIR spectroscopy convincingly demonstrates that, for a smaller sized water pool, the water molecules, even at the centre of the water pool, behave significantly different as compared to bulk water, an inference, which is missed by the previous vibrational lifetime measurements, and suggest an extensive slowdown of the hydrogen bond relaxation dynamics as compared to bulk water.
- Published
- 2021
29. Interaction of a Julolidine-Based Neutral Ultrafast Molecular Rotor with Natural DNA: Spectroscopic and Molecular Docking Studies
- Author
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Dipak K. Palit, Aruna K. Mora, Rajib Ghosh, Rahul Kalel, Sukhendu Nath, and Dilip D. Dhavale
- Subjects
Stereochemistry ,Molecular rotors ,010402 general chemistry ,Photochemistry ,01 natural sciences ,chemistry.chemical_compound ,Nitriles ,Materials Chemistry ,A-DNA ,Physical and Theoretical Chemistry ,Julolidine ,Fluorescent Dyes ,chemistry.chemical_classification ,010405 organic chemistry ,Biomolecule ,DNA ,Fluorescence ,0104 chemical sciences ,Surfaces, Coatings and Films ,Molecular Docking Simulation ,Spectrometry, Fluorescence ,chemistry ,Ultrashort pulse ,Neutral molecule ,Quinolizines - Abstract
Ultrafast molecular rotors (UMRs) are reported to be one of the best fluorescent sensors to study different microenvironments, including biomolecules. In the present work, we have explored the possibility of application of a julolidine-based neutral UMR, 9-(2,2-dicyano vinyl) julolidine (DCVJ), as a DNA sensor and studied its mode of binding with DNA in detail using spectroscopic and molecular docking techniques. Our spectroscopic studies indicate that association of DCVJ with DNA leads to a very large enhancement in its emission intensity. Detailed investigation reveals that, despite being a neutral molecule, binding of DCVJ with DNA is largely modulated in the presence of salt. Such an unusual salt effect has been explained by invoking the ion-dipole interaction between DCVJ and the phosphate backbone of DNA. The ion-dipole interaction has also been established by studying the interaction of DCVJ with nucleosides. Detailed time-resolved studies show that the twisting motion around the vinyl bond in DCVJ gets retarded to a great extent because of its association with DNA molecules. Through competitive binding studies, it has also been established that DCVJ also binds to DNA through intercalation. Finally, quantum chemical calculations and molecular docking studies have been performed to confirm the mode of binding of DCVJ with DNA.
- Published
- 2016
30. Controlled Sequestration of DNA Intercalated Drug by Polymer–Surfactant Supramolecular Assemblies
- Author
-
Sukhendu Nath, Prabhat K. Singh, and Aruna K. Mora
- Subjects
Macromolecular Substances ,Polymers ,Supramolecular chemistry ,macromolecular substances ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Micelle ,Surface-Active Agents ,Pulmonary surfactant ,Materials Chemistry ,Copolymer ,Animals ,Molecule ,Organic chemistry ,Physical and Theoretical Chemistry ,chemistry.chemical_classification ,technology, industry, and agriculture ,DNA ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Pharmaceutical Preparations ,chemistry ,Chemical engineering ,Cattle ,Absorption (chemistry) ,0210 nano-technology - Abstract
Triblock copolymer and surfactant based supramolecular assemblies have been used for the controlled sequestration of the DNA intercalator. The triblock copolymer micelles do not affect the molecules that are intercalated in the DNA. However, on addition of charged surfactant to the triblock copolymer micellar solution, sequestration of the intercalated molecules from DNA to the polymer-surfactant supramolecular assemblies takes place. Such sequestration of the intercalated molecules in the polymer-surfactant supramolecular assemblies has been explained on the basis of the charged surface formed in the polymer micelles due to the addition of surfactants. Sequestration of the intercalated molecules from the DNA to the polymer-surfactant supramolecular assemblies has been monitored through the ground state absorption, steady state, and time-resolved emission measurements. It is shown that the extent of sequestration of the intercalated molecules can be finely tuned by tuning the concentration of the surfactant in the triblock copolymer solution. Quantitative sequestration of the intercalated molecules by the supramolecular assemblies has been achieved. Such controlled sequestration of the DNA intercalated molecules by polymer-surfactant supramolecular assemblies can be used to study the binding of drug with DNA and may be useful in applications like detoxification in the case of drug overdose.
- Published
- 2016
31. Free volume dependence of an ionic molecular rotor in Fluoroalkylphosphate (FAP) based ionic liquids
- Author
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Sukhendu Nath, Prabhat K. Singh, and Aruna K. Mora
- Subjects
Inorganic chemistry ,Relaxation (NMR) ,Cationic polymerization ,General Physics and Astronomy ,Ionic bonding ,Quantum yield ,02 engineering and technology ,Atmospheric temperature range ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,chemistry.chemical_compound ,Viscosity ,chemistry ,Ionic liquid ,Physical chemistry ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
The emission properties of Thioflavin-T (ThT), a cationic molecular rotor, have been investigated in two fluoroalkylphosphate ([FAP]) anion based ionic liquids, namely, 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate and 1-(2-hydroxyethyl)-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, over a wide temperature range. The micro-viscosities of ionic liquids around ThT, measured from the emission quantum yield, are found to be quite different from their bulk viscosities. The temperature dependence of the viscosity and the emission quantum yield reveals that, despite the very low shear viscosity of these ILs, the non-radiative torsional relaxation has a strong dependence on the free volume of these [FAP] anion based ILs.
- Published
- 2016
32. Comparative studies of photophysics and exciton dynamics of different diphenylanthracene (DPA) nanoaggregates
- Author
-
Biswajit Manna, Sukhendu Nath, Amitabha Nandi, Neeraj Agarwal, and Rajib Ghosh
- Subjects
Anthracene ,General Chemical Engineering ,Diffusion ,Exciton ,Solid-state ,General Physics and Astronomy ,General Chemistry ,Dihedral angle ,Photochemistry ,Excimer ,chemistry.chemical_compound ,chemistry ,OLED ,Moiety - Abstract
Diphenyl derivatives of anthracene (DPA) have attracted extensive research interest in recent time due to their prospective application in organic light emitting diode (OLED) and other optoelectronic devices. Systematic investigation on the influence of phenyl substitution on optical properties of anthracene is lacking, even though the positions of phenyl substitution in the anthracene moiety are expected to alter the molecular interaction and molecular packing in solid state, having impact on photophysics and excitonic properties of these materials. In present work, we have investigated photophysics of three DPA derivatives namely, 2,6-diphenylanthracene, 1,8-diphenylanthracene and 9,10-diphenylanthracene in their nanoaggregate form. Owing to different positions and different dihedral angles (relative to anthracene plane) of the phenyl substituents, crystalline packing and intermolecular interaction are significantly modulated, resulting in diverse photophysical properties in nanoaggregated state. We have discussed the role of phenyl substituents on the interplay of exciton - excimer photophysics and exciton diffusion properties of these anthracene derivatives in relation to their potential application in OLED and photovoltaic devices.
- Published
- 2020
33. Structural and therapeutic properties of curcumin solubilized pluronic F127 micellar solutions and hydrogels
- Author
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J.S. Melo, Vinod K. Aswal, Haladhar Dev Sarma, Amit Kunwar, Sugam Kumar, Gunjan Verma, Sukhendu Nath, A. Tripathi, D.P. Chaudhari, and Ranjan Ganguly
- Subjects
Excipient ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Micelle ,chemistry.chemical_compound ,Materials Chemistry ,medicine ,Physical and Theoretical Chemistry ,Spectroscopy ,Aqueous solution ,Chemistry ,technology, industry, and agriculture ,Poloxamer ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Chemical engineering ,Self-healing hydrogels ,Drug delivery ,Micellar solutions ,Curcumin ,0210 nano-technology ,medicine.drug - Abstract
Curcumin, the principle active constituent of turmeric, is known to have broad range of therapeutic properties. Its poor aqueous solubility and low bioavailability however, act as constraints for its biomedical applications. Recent studies have shown that incorporation of curcumin in nano-carriers like micelles, vesicles, polymeric nanoparticles etc. can help in overcoming these issues and improve its therapeutic abilities quite significantly. In this manuscript, we report preparation of curcumin solubilized pluronic F127 micellar solutions and hydrogels, along with their structural and therapeutic properties as obtained from SANS, rheological, anti-cancer and wound healing studies. Pluronic F127 being approved by FDA has been used quite extensively as excipient for drug delivery applications. Curcumin solubilization in the aqueous pluronic F127 system was carried out by briefly heating the copolymer solutions with curcumin at 90 °C. The concentrations of curcumin thus obtained were found to be comparable to those obtained by conventional methods of solubilization like thin film hydration or solvent evaporation method, and three orders of magnitude higher than that in pure water. SANS and rheological studies show that curcumin solubilization does not bring about any significant change in the structural and rheological properties of F127 micellar solutions and hydrogels. Curcumin solubilized F127 micellar solutions can be reconstituted after lyophilization, suggesting that curcumin remains nano-dispersed in lyophilized state. Micellar encapsulated curcumin exhibits very good stability in solution state in ambient condition but fails to show cytotoxicity against MCF7 cancer cells, presumably due to shielding of curcumin by large corona region of F127 micelles. Micellar curcumin containing F127 hydrogels on the other hand, exhibit wound healing abilities in mice model upon topical application. The results give an account of how some of the therapeutic properties of curcumin are manifested under micellar encapsulation and the role of pluronic F127 as excipient in those therapeutic applications.
- Published
- 2020
34. Fluorescence quenching of 9-cyanoanthracene by metallo-octaethylporphyrins in cyanobenzene
- Author
-
Mihir Ghosh, Sukhendu Nath, Subrata Sinha, Aruna K. Mora, Biswajit Roy, and Koushik Majhi
- Subjects
Exergonic reaction ,Absorbance ,symbols.namesake ,Electron transfer ,Chemistry ,Excited state ,symbols ,General Chemistry ,Steady state (chemistry) ,Photochemistry ,Acceptor ,Photoinduced electron transfer ,Gibbs free energy - Abstract
Investigations are carried out on the nature of photoinduced electron transfer reactions within some metallo-octaethylporphyrin (zinc octaethylporphyrin and magnesium octaethylporphyrin) donors and acceptor 9-cyanoanthracene in cyanobenzene at 300 K by steady state and time-resolved spectroscopic methods. Acceptor is selectively excited at 366 nm and 374 nm for steady state and time-resolved measurements, respectively, where donor metalloporphyrins possess negligible absorbance. Evidence is found for simultaneous occurrence of Förster's type singlet–singlet energy transfer process along with electron transfer. High exergonic values of Gibbs free energy change for both forward and back electron transfer reactions indicate the possibility of occurrences of these two consecutive processes in the Marcus inverted region.
- Published
- 2015
35. Photoinduced electron transfer from zinc tetraphenylporphyrin to 2-nitrofluorene in polar solvent acetonitrile
- Author
-
Subrata Sinha, Aruna K. Mora, P. Hemant Kumar, Prakriti Ranjan Bangal, Mihir Ghosh, and Sukhendu Nath
- Subjects
Photoexcitation ,Electron transfer ,Chemistry ,General Chemical Engineering ,Excited state ,Ultrafast laser spectroscopy ,General Physics and Astronomy ,General Chemistry ,Steady state (chemistry) ,Photochemistry ,Acceptor ,Photoinduced electron transfer ,Marcus theory - Abstract
The possibility of intermolecular photoinduced ET (PET) is investigated in a novel donor–acceptor (D–A) system consisting of zinc tetraphenylporphyrin (ZnTPP) as donor and 2-nitrofluorene (2NF) as acceptor upon photoexcitation of the former moieties in polar solvent acetonitrile (ACN). The observed values (7.23 × 109 L/(mol s) and 7.04 × 109 L/(mol s)) of the fluorescence quenching rate constant from steady state and time-resolved data, respectively, are in good agreement with that (5.65 × 109 L/(mol s)) obtained from Marcus theory. Excited state absorption (ESA) from the S2 state of Soret excited ZnTPP to higher electronic states gives rise to broad transient absorption spectra in 560–700 nm region. Presence of 2NF leads to a faster decay (up to 100 ps time delay) of the ESA signal of ZnTPP at a probe wavelength of 620 nm. This indicates ultrafast ET from the S2 state (zero vibrational level) as well as the higher vibrational levels of the S1 state of ZnTPP to 2NF. Moreover, transient absorption kinetics at longer time delays (up to 7 ns) at a probe wavelength of 620 nm show the formation of a charge separated state due to ET from the S1 state (zero vibrational level) of the Soret excited ZnTPP to 2NF.
- Published
- 2015
36. Ultrafast torsional dynamics of Thioflavin-T in an anionic cyclodextrin cavity
- Author
-
Prabhat K. Singh, Aruna K. Mora, Sukhendu Nath, and Sushant Murudkar
- Subjects
chemistry.chemical_classification ,Cyclodextrin ,General Chemical Engineering ,Analytical chemistry ,General Physics and Astronomy ,General Chemistry ,Photochemistry ,Fluorescence ,Photon upconversion ,Hydrophobic effect ,chemistry ,Ionic strength ,Excited state ,Emission spectrum ,Spectroscopy - Abstract
Using sub-picosecond fluorescence upconversion spectroscopy, the effect of supramolecular confinement on the ultrafast excited state torsional dynamics of an amyloid fibril sensing dye, Thioflavin-T (ThT), is investigated in a novel cyclodextrin derivative, Sulphobutylether β-cyclodextrin (SBE-β-CD). The encapsulation of ThT inside the nanocavity of SBE-β-CD results in a significant increase in the emission intensity and the excited state lifetime of ThT when compared with native β-CD. Detailed analysis of the time-resolved emission spectra (TRES) shows that the time dependent changes in the integrated area, mean frequency and the width of the emission spectra are appreciably slower as compared with bulk water and native β-CD. These features suggest a significant confinement effect on the ultrafast torsional dynamics of ThT. The ionic strength of the medium significantly affects the complexation of ThT with SBE-β-CD, which indicates that the interaction between the host and the guest is predominantly electrostatic in nature. The results further suggest that the hydrophobic interaction in SBE-β-CD, although minor in contribution in the present case, is comparatively stronger than the native β-CD.
- Published
- 2015
37. Effect of fibrillation on the excited state dynamics of tryptophan in serum protein – A time-resolved fluorescence study
- Author
-
Sukhendu Nath, Aruna K. Mora, Sushant Murudkar, and Prabhat K. Singh
- Subjects
Chemistry ,General Chemical Engineering ,Tryptophan ,General Physics and Astronomy ,macromolecular substances ,General Chemistry ,Fibril ,Human serum albumin ,Fluorescence ,Residue (chemistry) ,Biochemistry ,Ionic strength ,Excited state ,medicine ,Molecule ,medicine.drug - Abstract
The aggregation of proteins into the amyloid fibrils is mainly responsible for several neurological diseases. Knowledge of dynamics in amyloid fibril is very essential to understand its biological activity. Although, the effects of environment like pH, ionic strength, temperature, etc. on the fibril have been studied extensively, studies on the dynamics of amyloid fibril and the role of water in fibril are scarce. In this article, we have reported the results on the excited state dynamics of amyloid fibrils formed by a well-known blood plasma protein, human serum albumin (HSA), at neutral pH. The sole tryptophan residue, W214, has been used as the intrinsic fluorescent probe to monitor its excited state dynamics. Steady-state and time-resolved fluorescence data suggests that the W214 becomes more closer to the quencher amino acid residues in the fibrillar phase than in the native protein. From detailed time-resolved emission measurements, it is shown that despite having a more ordered structure, the water molecules around W214 in amyloid fibril is more labile than that in the native protein. Fluorescence depolarization studies also indicate that the W214 residue is located in a relatively more flexible region of the ordered amyloid fibril than that in the native protein.
- Published
- 2015
38. An ultrafast molecular rotor based ternary complex in a nanocavity: a potential 'turn on' fluorescence sensor for the hydrocarbon chain
- Author
-
Sukhendu Nath, Sushant Murudkar, Aruna K. Mora, Tusar Bandyopadhyay, and Prabhat K. Singh
- Subjects
chemistry.chemical_classification ,Stereochemistry ,Chemistry ,General Physics and Astronomy ,Cavitand ,Photochemistry ,Fluorescence ,Molecular dynamics ,chemistry.chemical_compound ,Pulmonary surfactant ,Benzothiazole ,Physical and Theoretical Chemistry ,Ternary operation ,Ternary complex ,Alkyl - Abstract
Formation of a ternary complex by an ultrafast molecular rotor (UMR) with a macrocyclic cavitand has been investigated for the sensitive detection of the alkyl chain of a surfactant. A benzothiazole based UMR, Thioflavin-T (ThT), has been used as a fluorescent probe. It is shown that ThT forms a very weak inclusion complex with γ-cyclodextrin (γ-CD) with an association constant of 8.8 M(-1). However, the addition of a small amount of surfactant results in a significant increase in the emission intensity of ThT in γ-CD solution. From detailed steady-state and time-resolved fluorescence measurements and NMR studies, it has been inferred that the addition of the surfactant results in the formation of a ternary complex through the inclusion of its alkyl chain inside the γ-CD nanocavity. In such a ternary complex, the non-radiative torsional motion in ThT is largely prevented due to a large increase in the frictional force inside the nanocavity and results in a significant fluorescence enhancement. The formation of the binary and the ternary complexes in the present system has been further supported by the molecular docking and subsequent molecular dynamics simulation studies. The present result indicates that the inclusion complex with an UMR as a guest could be a potential candidate for the efficient detection of insoluble organic molecules, especially hydrocarbons.
- Published
- 2015
39. Ultrafast fluorescence spectroscopy reveals a dominant weakly-emissive population of fibril bound thioflavin-T
- Author
-
Aruna K. Mora, Sukhendu Nath, and Prabhat K. Singh
- Subjects
Amyloid ,Population ,macromolecular substances ,Fibril ,Sensitivity and Specificity ,Catalysis ,Fluorescence spectroscopy ,chemistry.chemical_compound ,mental disorders ,Materials Chemistry ,Insulin ,Benzothiazoles ,Spectroscopy ,education ,Fluorescent Dyes ,education.field_of_study ,Molecular Structure ,Chemistry ,Relaxation (NMR) ,Metals and Alloys ,General Chemistry ,Fluorescence ,Photon upconversion ,nervous system diseases ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Thiazoles ,Crystallography ,Spectrometry, Fluorescence ,Ceramics and Composites ,Biophysics ,Thioflavin ,Protein Binding - Abstract
In this communication, using sub-picosecond resolved fluorescence upconversion spectroscopy, we discover that despite a large fluorescence enhancement observed for thioflavin-T in insulin fibrils, the majority of fibril bound thioflavin-T undergoes efficient ultrafast conformational relaxation, and thus does not contribute to the characteristic fluorescence enhancement.
- Published
- 2015
40. TBP induced double cloud point in aqueous EO13PO30EO13 solutions: investigating the evolution of associated micellar characteristics as a function of temperature
- Author
-
Ranjan Ganguly, J. N. Sharma, Sukhendu Nath, Sanjukta A. Kumar, and Vinod K. Aswal
- Subjects
Cloud point ,Aqueous solution ,General Chemical Engineering ,General Chemistry ,Poloxamer ,Micelle ,Viscosity ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Micellar solutions ,Copolymer ,Organic chemistry ,Tributyl phosphate - Abstract
Pluronics are considered as potential materials for the removal of tributyl phosphate (TBP) from nuclear fuel reprocessing plants. Recent studies showed that solubilization of TBP in aqueous solution of Pluronic L64 reduces its cloud point (CP) and in addition, induces a second CP at low temperature. In this manuscript we have attempted to understand the origin of this lower CP (LCP) by carrying out DLS, SANS, viscosity and fluorescence measurement studies on 10% aqueous L64 solutions containing 60 mM TBP. The studies show that on approaching both LCP (≈25 °C) and the conventional or upper CP (UCP ≈ 42.5 °C), the copolymer solution exhibits a large increase in light scattering intensity and apparent micellar radius. Detailed studies suggest that whereas the copolymer micelles undergo a progressive growth on heating to the UCP, they form a micellar cluster upon cooling down to the LCP due to the onset of an inter-micellar attractive interaction. Although such clusters are known to form in micellar solutions of non ionic surfactants on approaching the UCP, their formation upon cooling is the first of its kind for them. The observed unusual behavior has possibly been triggered by dehydration of micellar corona caused by relocation of TBP from micellar core to corona upon cooling down to the LCP.
- Published
- 2015
41. Ultrafast molecular rotor based DNA sensor: An insight into the mode of interaction
- Author
-
Sukhendu Nath, Prabhat K. Singh, Aruna K. Mora, Sujana Jakka, and Sushant Murudkar
- Subjects
Chemistry ,General Chemical Engineering ,Intercalation (chemistry) ,General Physics and Astronomy ,General Chemistry ,Resonance (chemistry) ,Photochemistry ,Fluorescence ,chemistry.chemical_compound ,Benzothiazole ,Excited state ,Femtosecond ,Molecule ,DNA - Abstract
Benzothiazole based ultrafast molecular rotor, Thioflavin T (ThT), is a well known fluorescence sensor for nucleic acids. Thus, the knowledge of mode of interaction between ThT and DNA is very important for efficient utilization of such fluorescence sensors. In the present article, we have reported detail studies on the mode of interaction between ThT and a natural DNA using steady-state and femtosecond time-resolved transient emission techniques. Detail steady-state studies show that ThT binds strongly with natural DNA and causes a large change in its spectroscopic properties. Femtosecond transient emission studies show a substantial decrease in the torsional motion in the excited state of ThT bound to DNA molecules, indicating a strong interaction between them. It is observed that ThT binds to DNA through two modes of interaction. Studies with salt indicate that large fraction of ThT binds to DNA by electrostatic interaction, whereas, viscosity and resonance energy transfer studies indicate the intercalation of ThT with DNA molecules.
- Published
- 2014
42. Ultrafast Dynamics of Hydrogen Bond Breaking and Making in the Excited State of Fluoren-9-one: Time-Resolved Visible Pump-IR Probe Spectroscopic Study
- Author
-
Dipak K. Palit, Aruna K. Mora, Rajib Ghosh, and Sukhendu Nath
- Subjects
Hydrogen ,Chemistry ,Hydrogen bond ,Photodissociation ,Infrared spectroscopy ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Photoexcitation ,Absorption band ,Excited state ,Materials Chemistry ,Molecule ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
The fluoren-9-one (FL) molecule, with a single hydrogen bond-accepting site (C═O group), has been used as a probe for investigation of the dynamics of a hydrogen bond in its lowest excited singlet (S1) state using the subpicosecond time-resolved visible pump–IR probe spectroscopic technique. In 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), a strong hydrogen bond-donating solvent, the formation of an FL–alcohol hydrogen-bonded complex in the ground electronic (S0) state is nearly complete, with a negligible concentration of the FL molecule remaining free in solution. In addition to the presence of a band due to the hydrogen-bonded complex in the transient IR spectrum recorded immediately after photoexcitation of FL in HFIP solution, appearance of the absorption band due to a free C═O stretch provides confirmatory evidence of ultrafast photodissociation of hydrogen bonds in some of the complexes formed in the S0 state. The peak-shift dynamics of the C═O stretch bands reveal two major relaxation pathways, namely...
- Published
- 2017
43. Butanol solubilization in aqueous F127 solution: Investigating the enhanced micellar solvation and consequent improvement in gelation characteristics
- Author
-
Jahar Dey, Sukhendu Nath, Pratap Bahadur, Ranjan Ganguly, Vinod K. Aswal, Sanjukta A. Kumar, and Paresh Parekh
- Subjects
Butanols ,Poloxamer ,Micelle ,Fluorescence ,Colloid and Surface Chemistry ,Elastic Modulus ,Phase (matter) ,Scattering, Small Angle ,Copolymer ,Organic chemistry ,Physical and Theoretical Chemistry ,Micelles ,Aqueous solution ,Viscosity ,Chemistry ,Temperature ,technology, industry, and agriculture ,Solvation ,Surfaces and Interfaces ,General Medicine ,Solutions ,Neutron Diffraction ,Solubility ,Chemical engineering ,Volume fraction ,lipids (amino acids, peptides, and proteins) ,Mesoporous material ,Gels ,Biotechnology - Abstract
Pluronics(®) are an important class of non-ionic surfactants because of their rich phase behavior and numerous industrial and biomedical applications. F127, an FDA approved Pluronic(®) is the most prominent member amongst them owing to its potential uses as vehicle for drug delivery and template for the fabrication of mesoporous materials. A cubic micellar gel formed by this copolymer above 15 wt% concentration is the commonly used form of self assembled structure for these applications. In this manuscript we report SANS, fluorescence and rheological studies on the effect of n-butanol on gelation characteristics of aqueous F127 solutions. The studies show that solubilization of n-butanol results in a large increase in viscosity of micellar solution at a fixed copolymer concentration, and leads to the formation of stiff gel at F127 concentration as low as 9 wt%. SANS and fluorescence studies attribute this to enhancement in micellar solvation due to solubilization of n-butanol. Quite interestingly, SANS studies show that n-butanol induced F127 gels form at significantly lower micellar volume fraction than the pure F127 gels. The observed improvement in gelation characteristics can have important bearing with the application in making mesoporous materials since n-butanol is used as co-surfactant to control pore size of such structures formed with F127 gels as template.
- Published
- 2014
44. Additive induced core and corona specific dehydration and ensuing growth and interaction of Pluronic F127 micelles
- Author
-
Rajib Ganguly, Sugam Kumar, Jahar Dey, Vinod K. Aswal, Kochi Ismail, and Sukhendu Nath
- Subjects
Butanols ,Poloxamer ,Sodium Chloride ,Micelle ,Biomaterials ,Colloid and Surface Chemistry ,Rheology ,Phase (matter) ,Scattering, Small Angle ,Copolymer ,Transition Temperature ,Organic chemistry ,Desiccation ,Micelles ,Fluorescent Dyes ,Drug Carriers ,Pyrenes ,Aqueous solution ,Chemistry ,Water ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Neutron Diffraction ,Spectrometry, Fluorescence ,Chemical engineering ,Drug delivery ,Mesoporous material ,Hydrophobic and Hydrophilic Interactions - Abstract
Pluronic F127 is considered to be the most prominent member amongst Pluronics owing to its uses in the fields of drug delivery and fabrication of mesoporous materials. Though extensive studies were carried out on the phase behavior of this copolymer, the effect of additives on restructuring and growth processes of its micelles is not understood yet. In this manuscript we report DLS, SANS, fluorescence and rheological studies on the effects of NaCl and butan-1-ol on the properties of Pluronic F127 micelles in the aqueous medium. The studies show that corona specific micellar dehydration by NaCl induces inter micellar attraction and consequent formation of micellar clusters. Core specific micellar dehydration by butan-1-ol on the other hand, brings about sphere-to-rod micellar shape transition on approaching the cloud point of copolymer solutions. A room temperature sphere-to-rod shape transition of Pluronic F127 micelles can also be induced in the combined presence of butan-1-ol and NaCl. Observation of such micellar shape transition in aqueous Pluronic F127 system is first of its kind, which can have important bearing with their application in mesoporous structure formation and drug delivery.
- Published
- 2014
45. Dynamics under confinement: torsional dynamics of Auramine O in a nanocavity
- Author
-
Sushant Murudkar, Aruna K. Mora, Sukhendu Nath, and Prabhat K. Singh
- Subjects
Auramine O ,Chemistry ,General Chemical Engineering ,Analytical chemistry ,General Chemistry ,Electrostatics ,Photon upconversion ,Hydrophobic effect ,chemistry.chemical_compound ,Chemical physics ,Excited state ,Molecule ,Emission spectrum ,Spectroscopy - Abstract
The effect of confinement on the ultrafast torsional relaxation dynamics of a well-known ultrafast molecular rotor (UMR) and a recently reported amyloid fibril sensor, Auramine O (AuO), is investigated inside the nanocavity of a novel cyclodextrin derivative, sulphobutylether β-cyclodextrin (SBE-β-CD), using sub-pisosecond fluorescence upconversion spectroscopy. The nanocavity of SBE-β-CD induces a significant increase in the emission intensity and results in a slower transient decay trace of Auramine O when compared to the native β-CD. Detailed analysis of the time-resolved emission spectral features shows that the time-dependent changes in both the mean frequency and the width of the emission spectra are considerably slower as compared to bulk water and native β-CD, which suggests that the excited state torsional dynamics of AuO has been significantly affected in the nanocavity of SBE-β-CD. This effect on the torsional dynamics has been attributed to the perturbation of the water structure inside the nanocavity of SBE-β-CD which suppresses the ability of fast collective solvent reorientation motion to promote the excited-state torsional relaxation of Auramine O. The effect of ionic strength of the medium is invoked to analyze the contribution of electrostatic interactions towards the binding of AuO with SBE-β-CD and is corroborated well by computation of electrostatic potentials for the host molecules. The results also suggest that the hydrophobic interaction provided by the SBE-β-CD is larger than the native β-CD.
- Published
- 2014
46. Photophysics of Soret-excited free base tetraphenylporphyrin and its zinc analog in solution
- Author
-
Subrata Sinha, Aruna K. Mora, Mihir Ghosh, Asit K. Chandra, Alakananda Hajra, and Sukhendu Nath
- Subjects
Models, Molecular ,Physics::Biological Physics ,Porphyrins ,Solvatochromism ,Analytical chemistry ,Quantum yield ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Solutions ,Zinc ,chemistry.chemical_compound ,Dipole ,symbols.namesake ,Spectrometry, Fluorescence ,chemistry ,Polarizability ,Stokes shift ,Excited state ,Tetraphenylporphyrin ,symbols ,Ground state ,Instrumentation ,Spectroscopy - Abstract
Photophysical properties of free base tetraphenylporphyrin and its zinc analog are investigated in detail in solvents of varying polarity by using steady state and time-resolved techniques. Both the porphyrins are excited at the Soret band to have better signal-to-noise ratio. Also, the fluorescence emission measurements are carried out by using dilute solutions (∼10−7 mol/L) of the fluorophores in order to minimize the self-quenching effect. It is observed that the steady state absorption and emission characteristics of the porphyrin molecules are mainly affected by polarizability (via refractive index) rather than polarity (via dielectric constant) of the moderate to highly polar solvents. As the molecules are highly symmetric in the ground state, the associated dipole moments are found to be very low from quantum chemical calculations performed by density functional theory method by using Gaussian 03 package. The dipole moments associated with the first excited singlet state of the porphyrins are computed by applying solvatochromic Stokes’ shift method. To the best of our knowledge, this is the first attempt to calculate the excited state dipole moments of the porphyrins used in the present investigations. Also, fluorescence quantum yield, fluorescence lifetime of the first excited singlet state, radiative and non-radiative rate constants of the porphyrins are reported in solvents of varying polarity.
- Published
- 2013
47. Ultrafast excited state dynamics of 1-nitropyrene: Effect of H-bonding
- Author
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N.S.K. Gowthaman, Tulsi Mukherjee, Aruna K. Mora, Prabhat K. Singh, Sushant Murudkar, and Sukhendu Nath
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Physics::Biological Physics ,Quantitative Biology::Biomolecules ,General Chemical Engineering ,General Physics and Astronomy ,General Chemistry ,Photochemistry ,Condensed Matter::Soft Condensed Matter ,Solvent ,chemistry.chemical_compound ,Intersystem crossing ,chemistry ,Excited state ,Singlet state ,Emission spectrum ,Physics::Chemical Physics ,Triplet state ,Solvent effects ,Protic solvent - Abstract
Ultrafast excited state dynamics of 1-nitropyrene has been carried out using femtosecond fluorescence upconversion technique. Detailed time-resolved emission measurements were performed in protic and aprotic solvents of similar polarity. It is seen that although the singlet–triplet energy gap in polar solvents is quite large, the excited state decay shows intersystem crossing in sub-picosecond time scale as observed for nonpolar solvents with isoenergetic singlet and triplet state. The appearance of the sub-picosecond decay component in polar solvents has been explained on the basis of the dynamical nature of the solvent relaxation process. Further, the contribution of the sub-picosecond decay component is much more for the solvent with slower solvent relaxation time. Time-resolved area normalized emission spectra (TRANES) show the presence of two emissive species for 1-nitropyrene in aprotic solvent while only one emissive species has been observed in protic solvent. The additional emissive species in aprotic solvent has been assigned to the structurally relaxed excited singlet state formed due to the rotation of the nitro group around the pyrene moiety. However, such rotation of the nitro group is prevented in protic solvent due to the formation of H-bonded complex between the solute and the solvent. Formation of H-bonding between protic solvent and nitropyrene is also confirmed by quantum chemical calculations.
- Published
- 2013
48. Fluorescence self-quenching of tetraphenylporphyrin in liquid medium
- Author
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Sukhendu Nath, Mihir Ghosh, Alakananda Hajra, and Subrata Sinha
- Subjects
Quenching (fluorescence) ,Chemistry ,Biophysics ,Analytical chemistry ,General Chemistry ,Fluorescence in the life sciences ,Condensed Matter Physics ,Photochemistry ,Biochemistry ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Fluorescence spectroscopy ,chemistry.chemical_compound ,Resonance fluorescence ,Tetraphenylporphyrin ,Fluorescence cross-correlation spectroscopy ,Laser-induced fluorescence - Abstract
Self-quenching of the fluorescence emission of tetraphenylporphyrin at high concentrations in toluene at the ambient temperature (300 K) is discussed in detail based on steady state and time-resolved fluorescence measurements. The fluorescence self-quenching is mainly attributed to re-absorption effect and the Forster type resonance energy transfer process (homotransfer). The re-absorption effect is found to deform the fluorescence emission spectra significantly in energy positions as well as relative intensities of different peaks at high concentrations. Nearly ideal fluorescence emission spectra are observed at a concentration ∼10 −7 mol/L. Moreover, there is an apparent enhancement of the fluorescence lifetime value of tetraphenylporphyrin in toluene at high concentrations, especially on the blue side of the fluorescence emission spectra. To the best knowledge of the authors, this is the first detail report on the fluorescence self-quenching of porphyrins in liquid medium. This finding carries great importance in view of the widespread research on porphyrins in the fields of solar light harvesting, artificial photosynthesis, photodynamic therapy, etc.
- Published
- 2013
49. Molecular Recognition Controlled Delivery of a Small Molecule from a Nanocarrier to Natural DNA
- Author
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Sukhendu Nath and Prabhat K. Singh
- Subjects
Circular dichroism ,Nanotechnology ,Micelle ,Surface-Active Agents ,Molecular recognition ,Materials Chemistry ,Molecule ,Benzothiazoles ,Physical and Theoretical Chemistry ,Micelles ,chemistry.chemical_classification ,Cyclodextrins ,Drug Carriers ,Cyclodextrin ,Chemistry ,Circular Dichroism ,Sodium Dodecyl Sulfate ,DNA ,Small molecule ,Nanostructures ,Surfaces, Coatings and Films ,Thiazoles ,Biophysics ,Nanocarriers ,Drug carrier ,Hydrophobic and Hydrophilic Interactions - Abstract
Controlled and targeted release of an active small molecule at the site of demand is very crucial in pharmaceutical applications. In the present article, we have reported a very simple yet unique chemical system which can be used for the controlled and quantitative transfer of a small molecule from a nanocarrier to natural DNA using an external stimulus. Due to the high sensitivity of emission intensity toward its microenvironments, an ultrafast molecular rotor has been used as a spectroscopic probe. SDS micelle has been used as a nanocarrier and the cyclodextrin molecules are used as an external stimulus. The molecular recognition property of the stimulus toward the hydrophobic chain of the surfactant molecules has been utilized for controlled transfer of the small molecule from the nanocarrier to DNA. Through detailed steady state and time-resolved spectroscopic studies, it has been demonstrated that quantitative transfer of the small molecules from nanocarrier to the natural DNA molecules could be achieved. The present chemical system might be very promising in the field of controlled and targeted drug delivery.
- Published
- 2013
50. Solubilization of Parabens in Aqueous Pluronic Solutions: Investigating the Micellar Growth and Interaction as a Function of Paraben Composition
- Author
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Vinod K. Aswal, Mehul Khimani, Rajib Ganguly, Pratap Bahadur, and Sukhendu Nath
- Subjects
Preservative ,Aqueous solution ,Chromatography ,Transition temperature ,Parabens ,Water ,Viscometer ,Poloxamer ,Micelle ,Polyethylene Glycols ,Surfaces, Coatings and Films ,Paraben ,chemistry.chemical_compound ,Solubility ,chemistry ,Propylene Glycols ,Materials Chemistry ,Transition Temperature ,Composition (visual arts) ,Physical and Theoretical Chemistry ,Hydrophobic and Hydrophilic Interactions ,Micelles - Abstract
The influence of methyl paraben (MP) and butyl paraben (BP) on the aggregation characteristics of Pluronics in an aqueous medium has been investigated by DLS, SANS, viscometry, and fluorescence measurement techniques. Parabens are extensively used as preservatives in cosmetic, pharmaceutical, and food products. In this paper, we show that their influence on the restructuring and growth of Pluronics micelles vary quite significantly with their aqueous solubility and with the composition of Pluronics. In the case of P105 and P104, MP reduces the sphere-to-rod transition temperature down to room temperature, but BP with significantly less aqueous solubility than MP suppresses such micellar transition and leads to the formation of micellar clusters due to the onset of intermicellar attractive interaction. In the case of more hydrophobic Pluronic P103, on the other hand, both MP and BP are able to induce rapid room temperature sphere-to-rod micellar growth, which is not observed in the presence of water structure making salts like NaCl and Na(3)PO(4). These observations have been attributed to modulation of growth and restructuring processes of the Pluronic micelles arising due to different locations of parabens within the micellar corona as determined by their aqueous solubility and the hydrophobicity of the Pluronics.
- Published
- 2012
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