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Rovnyak D, He J, Kong S, Eckenroad KW, Manley GA, Geffert RM, Krout MR, Strein TG. Determining sequential micellization steps of bile salts with multi-CMC modeling. J Colloid Interface Sci 2023; 644:496-508. [PMID: 37146486 DOI: 10.1016/j.jcis.2023.03.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 03/02/2023] [Accepted: 03/23/2023] [Indexed: 05/07/2023]
Abstract
HYPOTHESIS Bile salts exhibit complex concentration-dependent micellization in aqueous solution, rooted in a long-standing hypothesis of increasing size in bile aggregation that has historically focused on the measurement of only one CMC detected by a given method, without resolving successive stepwise aggregates. Whether bile aggregation is continuous or discrete, at what concentration does the first aggregate form, and how many aggregation steps occur, all remain as open questions. EXPERIMENTS Bile salt critical micelle concentrations (CMCs) were investigated with NMR chemical shift titrations and a multi-CMC phase separation modeling approach developed herein. The proposed strategy is to establish a correspondence of the phase separation and mass action models to treat the first CMC; subsequent micellization steps, involving larger micelles, are then treated as phase separation events. FINDINGS The NMR data and the proposed multi-CMC model reveal and resolve multiple closely spaced sequential preliminary, primary, and secondary discrete CMCs in dihydroxy and trihydroxy bile salt systems in basic (pH 12) solutions with a single model of one NMR data set. Complex NMR data are closely explained by the model. Four CMCs are established in deoxycholate below 100 mM (298 K, pH 12): 3.8 ± 0.5 mM, 9.1 ± 0.3 mM, 27 ± 2 mM, and 57 ± 4 mM, while three CMCs were observed in multiple bile systems, also under basic conditions. Global fitting leverages the sensitivity of different protons to different aggregation stages. In resolving these closely spaced CMCs, the method also obtains chemical shifts of these spectroscopically inaccessible (aka dark) states of the distinct micelles.
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Affiliation(s)
- David Rovnyak
- Dent Drive, Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA.
| | - Jiayi He
- University of Pennsylvania, Department of Chemistry, 231 S. 34 Street, Philadelphia, PA 19104-6323, USA.
| | - Sophie Kong
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, 1700 4th St, San Francisco, CA 94158, USA.
| | - Kyle W Eckenroad
- Bristol Myers Squibb, 1 Squibb Drive, 92-218 New Brunswick, NJ 08901, USA.
| | - Gregory A Manley
- AB SCIEX LLC, 500 Old Connecticut Path, Framingham, MA 01701, USA
| | - Raeanne M Geffert
- The University of North Carolina at Chapel Hill, UNC Eshelman School of Pharmacy, Division of Pharmacotherapy and Experimental Therapeutics, Kerr Hall, Campus Box 7569, Chapel Hill, NC 27599-7569, USA
| | - Michael R Krout
- Dent Drive, Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA.
| | - Timothy G Strein
- Dent Drive, Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA.
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Chandra Maity N, Baksi A, Kumbhakar K, Biswas R. Impact and Structure of Water in Aqueous Octanol Mixtures: Hz-GHz Dielectric Relaxation Measurements and Computer Simulations. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Mukherjee K, Kumbhakar K, Biswas R. Dynamics of a based polymer gel Electrolyte: A combined frequency dependent dielectric relaxation and Time-resolved fluorescence spectroscopic study. J Mol Liq 2022; 360:119491. [DOI: 10.1016/j.molliq.2022.119491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
Hydrogels of bile acids and their salts are promising materials for drug delivery, cellular immobilization, and other applications. However, these hydrogels are poorly understood at the molecular level, and further study is needed to allow improved materials to be created by design. We have used NMR spectroscopy to probe hydrogels formed from mixtures of formic acid and sodium deoxycholate (NaDC), a common bile acid salt. By assaying the ratio of deoxycholate molecules that are immobilized as part of the fibrillar network of the hydrogels and those that can diffuse, we have found that 65% remain free under typical conditions. The network appears to be composed of both the acid and salt forms of deoxycholate, possibly because a degree of charge inhibits excessive aggregation and precipitation of the fibrils. Spin-spin relaxation times provided a molecular-level estimate of the temperature of gel-sol transition (42 °C), which is virtually the same as the value determined by analyzing macroscopic parameters. Saturation transfer difference (STD) NMR spectroscopy established that formic acid, which is present mainly as formate, is not immobilized as part of the gelating network. In contrast, HDO interacts with the network, which presumably has a surface with exposed hydrophilic groups that form hydrogen bonds with water. Moreover, the STD NMR experiments revealed that the network is a dynamic entity, with molecules of deoxycholate associating and dissociating reversibly. This exchange appears to occur preferentially by contact of the hydrophobic edges or faces of free molecules of deoxycholate with those of molecules immobilized as components of the network. In addition, DOSY experiments revealed that gelation has little effect on the diffusion of free NaDC and HDO.
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Affiliation(s)
- Puzhen Li
- Département de Chimie, Université de Montréal, Montréal, Québec H2V 0B3 Canada
| | - Cédric Malveau
- Département de Chimie, Université de Montréal, Montréal, Québec H2V 0B3 Canada
| | - X X Zhu
- Département de Chimie, Université de Montréal, Montréal, Québec H2V 0B3 Canada
| | - James D Wuest
- Département de Chimie, Université de Montréal, Montréal, Québec H2V 0B3 Canada
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Mukherjee K, Das S, Rajbangshi J, Tarif E, Barman A, Biswas R. Temperature-Dependent Dielectric Relaxation in Ionic Acetamide Deep Eutectics: Partial Viscosity Decoupling and Explanations from the Simulated Single-Particle Reorientation Dynamics and Hydrogen-Bond Fluctuations. J Phys Chem B 2021; 125:12552-12567. [PMID: 34752087 DOI: 10.1021/acs.jpcb.1c07299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here temperature-dependent (293 ≤ T (K) ≤ 336) dielectric relaxation (DR) measurements of (acetamide + LiBr/NO3-/ClO4-) deep eutectic solvents (DESs) in the frequency window of 0.2 ≤ ν (GHz) ≤ 50 and explore, via molecular dynamics simulations, the relative roles for the collective single-particle reorientational relaxations and the H-bond dynamics of acetamide in the measured DR response. In addition, DR measurements of neat molten acetamide were performed. Recorded DR spectra of these DESs require multi-Debye fits and produce well-separated DR time scales that are spread over several picoseconds to ∼1 ns. Simulations suggest DR time scales derive contributions from both the collective reorientational (Cl(t)) relaxation and structural H-bond (CHB(t)) dynamics of acetamide. A good correlation between the measured and simulated activation energies further reveals a strong connection between the measured DR and the simulated Cl(t) and CHB(t). Average DR times exhibit a strong fractional viscosity dependence, suggesting substantial microheterogeneity in these media. Simulations of Cl(t) and CHB(t) reveal strong stretched exponential relaxations with a stretching exponent, 0.4 ≤ β ≤ 0.7. The ratio between the average reorientational correlation times of first and second ranks, ⟨τ⟩l=1/⟨τ⟩l=2, deviates appreciably from Debye's l(l+1) law for homogeneous media. Importantly, a pronounced translation-rotation decoupling between the simulated reorientation and center-of-mass diffusion times was observed.
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Kumbhakar K, Dey A, Mondal A, De P, Biswas R. Interactions and Dynamics in Aqueous Solutions of pH-Responsive Polymers: A Combined Fluorescence and Dielectric Relaxation Study. J Phys Chem B 2021; 125:6023-6035. [PMID: 34057364 DOI: 10.1021/acs.jpcb.1c03435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Interaction and dynamics of aqueous solutions of pH-responsive smart polymers are investigated via steady-state, time-resolved fluorescence emission spectroscopy with the help of external local reporter coumarin 153 (C153), while MHz to GHz dielectric relaxation spectroscopic (DRS) measurement reports the intrinsic medium relaxation features. A series of pH-responsive random copolymers (DPL-DP60) comprising of a pH-responsive moiety 2-((leucinyl)oxy)ethyl methacrylate (l-Leu-HEMA) and hydrophobic methyl methacrylate (MMA) are synthesized and characterized. A balance between the pH-responsive (l-Leu-HEMA) and the hydrophobic (MMA) content dictates the phase transition pH, which is found to be ∼5-7 for these aqueous copolymer solutions (1 mg/mL). Dynamic light scattering measurements in aqueous solutions of these polymers reflect a small particle size (∼2-8 nm) at solution pH below their individual phase transition pH, while a large particle size (∼140-340 nm) forms beyond their phase transition pH. No signature of a phase transition pH-driven abrupt change in static and dynamic properties of aqueous polymer solutions has been registered from pH-dependent dielectric relaxation as well as solute (C153)-centric fluorescence measurements. A significant impact of varying the l-Leu-HEMA/MMA segment ratio on steady-state fluorescence emission and rotational anisotropy decay of the fluorophore solute (C153) has been observed. MHz to GHz DRS in aqueous solutions of these pH-responsive polymers reflects bulk water-like dielectric features.
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Affiliation(s)
- Kajal Kumbhakar
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Asmita Dey
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 Nadia, West Bengal, India
| | - Amrita Mondal
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Priyadarsi De
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 Nadia, West Bengal, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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Kumbhakar K, Saha B, De P, Biswas R. Cloud Point Driven Dynamics in Aqueous Solutions of Thermoresponsive Copolymers: Are They Akin to Criticality Driven Solution Dynamics? J Phys Chem B 2019; 123:11042-11054. [PMID: 31794221 DOI: 10.1021/acs.jpcb.9b07840] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cloud point driven interaction and relaxation dynamics of aqueous solutions of amphiphilic thermoresponsive copolymers were explored through picosecond resolved and steady state fluorescence measurements employing hydrophilic (coumarin 343, C343) and hydrophobic (coumarin 153, C153) solute probes of comparable sizes. These thermoresponsive random copolymers, with tunable cloud point temperatures (Tcp's) between 298 and 323 K, were rationally designed first and then synthesized via reversible addition-fragmentation chain transfer (RAFT) copolymerization of methyl methacrylate (MMA) and poly(ethylene glycol) monomethyl ether methacrylate (PEGMA). Subsequently, copolymers were characterized by NMR spectroscopy and size exclusion chromatography (SEC). A balance between the hydrophilic (PEGMA) and the hydrophobic (MMA) content dictates the critical aggregation concentration (CAC), with CAC ∼ 2-14 mg/L for these copolymers in aqueous media. No abrupt changes in the steady state spectral features of both C153 and C343 in the aqueous solutions of these polymers near but below the cloud point temperatures were observed. Interestingly, spectral properties of C153 in these solutions show the impact of hydrophobic/hydrophilic interaction balance but not by those of C343. More specifically, C153 reported a blue shift (relative to that in neat water) and heterogeneity in its local environment. This suggested different locations for the hydrophilic (C343) and the hydrophobic (C153) probes. In addition, the excited state fluorescence lifetime (⟨τlife⟩) of C153 increased with the increase of hydrophobic (MMA) content in these copolymers. However, C343 reported no such variations, although fluorescence anisotropy decays for both solutes were significantly slowed down in these aqueous solutions compared to neat water. Anisotropy decays indicated bimodal time-dependent friction for these solutes in aqueous solutions of these copolymers but monomodal in neat water. A linear dependence of the average rotational relaxation rates (⟨krot⟩ = ⟨τrot⟩-1) of the type ⟨krot⟩ ∝ (|T - Tcp|/Tcp)γ with negative values for the exponent γ was observed for both solutes. No slowing down of the solute rotation with temperature approaching the Tcp was detected; rather, rotation became faster upon increasing the solution temperature, suggesting domination of the local friction.
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Affiliation(s)
- Kajal Kumbhakar
- Chemical, Biological and Macromolecular Sciences (CBMS) , S. N. Bose National Centre for Basic Sciences , JD Block, Sector III, Salt Lake, Kolkata 700106 , India
| | - Biswajit Saha
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur 741246 , Nadia, West Bengal , India
| | - Priyadarsi De
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences , Indian Institute of Science Education and Research Kolkata , Mohanpur 741246 , Nadia, West Bengal , India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS) , S. N. Bose National Centre for Basic Sciences , JD Block, Sector III, Salt Lake, Kolkata 700106 , India
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Mukherjee K, Barman A, Biswas R. Hydration dynamics in aqueous Pluronic P123 solution: Concentration and temperature dependence. J Chem Phys 2019; 151:184901. [PMID: 31731866 DOI: 10.1063/1.5124526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Here, we report the concentration (0 ≤ wt. % ≤ 30) and temperature (293 ≤ T/K ≤ 318) dependent structural and dynamical changes in an aqueous solution of a triblock copolymer (Pluronic P123) using dielectric relaxation spectroscopy (DRS), covering a frequency regime, 0.2 ≤ ν/GHz ≤ 50. Remarkable existence of slow water molecules, ∼2 times slower than bulk type water, along with bulk-like water molecules has been detected in the present DR measurements. Differential scanning calorimetric measurements support this DR observation. The signature of the sol-gel phase transition (∼15.0 wt. %, 293 K) and temperature induced extensive dehydration (>60%) for P123 molecules, which are the other notable findings of the present work. Moreover, the rate of dehydration with temperature has been found to depend on the phase of the medium. However, dehydration follows a nonlinear pattern in both sol and gel phases. A subnanosecond (∼90 ps) component, possibly originating from the hydrogen bond relaxation dynamics of the terminal C-O-H of polymer chains, has also been observed.
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Affiliation(s)
- Kallol Mukherjee
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Anjan Barman
- Condensed Matter Physics and Material Sciences (CMPMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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Tarif E, Mukherjee K, Kumbhakar K, Barman A, Biswas R. Dynamics at the non-ionic micelle/water interface: Impact of linkage substitution. J Chem Phys 2019; 151:154902. [DOI: 10.1063/1.5121334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ejaj Tarif
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Kallol Mukherjee
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Kajal Kumbhakar
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Anjan Barman
- Condensed Matter Physics and Material Sciences (CMPMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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Kumbhakar K, Tarif E, Mukherjee K, Biswas R. Solvent dependent relaxation dynamics in lithium ion battery electrolytes: Coupling to medium friction. J Mol Liq 2019; 290:111225. [DOI: 10.1016/j.molliq.2019.111225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Tarif E, Saha B, Mukherjee K, De P, Biswas R. Exploring Aqueous Solution Dynamics of an Amphiphilic Diblock Copolymer: Dielectric Relaxation and Time-Resolved Fluorescence Measurements. J Phys Chem B 2019; 123:5892-5901. [DOI: 10.1021/acs.jpcb.9b00889] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ejaj Tarif
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Biswajit Saha
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, West Bengal, India
| | - Kallol Mukherjee
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Priyadarsi De
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, West Bengal, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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Mukherjee K, Schwaab G, Havenith M. Cation-specific interactions of protein surface charges in dilute aqueous salt solutions: a combined study using dielectric relaxation spectroscopy and Raman spectroscopy. Phys Chem Chem Phys 2018; 20:29306-29313. [PMID: 30444249 DOI: 10.1039/c8cp05011b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We exploited glycine as a zwitterionic model system to experimentally probe the cation specific interaction of protein surface charges in dilute (≤0.25 mol L-1) aqueous solutions of four biologically relevant inorganic salts, NaCl, KCl, MgCl2 and CaCl2, via dielectric relaxation spectroscopy (DRS) and Raman spectroscopy. Glycine is the simplest building block of proteins and it exposes the same charged groups (carboxylate and ammonium) to the solvent that dominate the protein-water interface. As a counter ion, we selected Cl- due to its biological importance. For all systems, we performed simultaneous fitting of the real (ε') and imaginary (ε″) parts of the dielectric functions, assuming a multimodal relaxation model, obtained from concentration dependent dielectric measurements at ∼293 K. We observe a reduction of the dielectric amplitude for the glycine relaxation while the corresponding time constant shows only small (<7%) deviations compared to aqueous glycine solutions. We propose that the observed reduction in dielectric amplitude is due to a reduction of the effective dipole moment (µeff) of zwitterionic glycine caused by the interaction of glycine with the ion even at very low (0.05 M) salt concentrations. The interaction between divalent metal ions and zwitterionic glycine is increased compared to the monovalent cation-zwitterion interaction; a finding that is also supported by Raman spectroscopy. Our combined dielectric relaxation and Raman spectroscopic study indicates that ion-glycine interactions are weak and mediated by the solvent. Cation-specificity of protein surface charges is also observed in dilute salt solutions (≤0.25 mol L-1), where electrostatic interactions dominate.
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Affiliation(s)
- K Mukherjee
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Physical Chemistry 2, Germany.
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Sett R, Guchhait N. Differential Perturbation of the Protrotropic Equilibrium of a Biological Photosensitizer within Bile Salt Aggregates of Varying Hydrophobicity: A Fluorimetric Investigation. Photochem Photobiol 2017; 94:328-337. [PMID: 29164617 DOI: 10.1111/php.12863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/27/2017] [Indexed: 12/01/2022]
Abstract
The present work reveals the binding interactions of a credible cancer cell photosensitizer, harmane (HM), with some selected bile salt aggregates of dissimilar hydrophobicity viz. sodium deoxycholate (NaDC), sodium cholate (NaC) and sodium taurocholate (NaTC). The explicit variation of the prototropic equilibrium of the photosensitizer both in the ground and excited state has been utilized to scrutinize the interaction phenomena. Differential modulation in the prototropic equilibrium of HM in the aforesaid aggregates has been explained on the basis of the structural dissimilarities of the bile salt monomers. The contrived hydrophobic surroundings provided by the aggregates have been reflected on the spectroscopic results, especially in the time-resolved fluorescence and the rotational dynamical behavior of the molecule of interest. Slow solvent reorientation time with regard to the lifetime of HM proliferated by the red-edge effect in two specific bile salts namely NaC and NaTC, whereas its absence in NaDC aggregates has also been elucidated on the basis of accessibility of the solvent molecules within the aggregates.
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Affiliation(s)
- Riya Sett
- Department of Chemistry, University of Calcutta, Calcutta, India
| | - Nikhil Guchhait
- Department of Chemistry, University of Calcutta, Calcutta, India
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