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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] [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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2
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Meier AR, Yehl JB, Eckenroad KW, Manley GA, Strein TG, Rovnyak D. Stepwise Aggregation of Cholate and Deoxycholate Dictates the Formation and Loss of Surface-Available Chirally Selective Binding Sites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:6489-6501. [PMID: 29733655 DOI: 10.1021/acs.langmuir.8b00467] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bile salts are facially amphiphilic, naturally occurring chemicals that aggregate to perform numerous biochemical processes. Because of their unique intermolecular properties, bile salts have also been employed as functional materials in medicine and separation science (e.g., drug delivery, chiral solubilization, purification of single-walled carbon nanotubes). Bile micelle formation is structurally complex, and it remains a topic of considerable study. Here, the exposed functionalities on the surface of cholate and deoxycholate micelles are shown to vary from one another and with the micelle aggregation state. Collectively, data from NMR and capillary electrophoresis reveal preliminary, primary, and secondary stepwise aggregation of the salts of cholic (CA) and deoxycholic (DC) acid in basic conditions (pH 12, 298 K), and address how the surface availability of chirally selective binding sites is dependent on these sequential stages of aggregation. Prior work has demonstrated sequential CA aggregation (pH 12, 298 K) including a preliminary CMC at ca. 7 mM (no chiral selection), followed by a primary CMC at ca. 14 mM that allows chiral selection of binaphthyl enantiomers. In this work, DC is also shown to form stepwise preliminary and primary aggregates (ca. 3 mM DC and 9 mM DC, respectively, pH 12, 298 K) but the preliminary 3 mM DC aggregate is capable of chirally selective solubilization of the binaphthyl enantiomers. Higher-order, secondary bile aggregates of each of CA and DC show significantly degraded chiral selectivity. Diffusion NMR reveals that secondary micelles of CA exclude the BNDHP guests, while secondary micelles of DC accommodate guests, but with a loss of chiral selectivity. These data lead to the hypothesis that secondary aggregates of DC have an exposed binding site, possibly the 7α-edge of a bile dimeric unit, while secondary CA micelles do not present binding edges to the solution, potentially instead exposing the three alcohol groups on the hydrophilic α-face to the solution.
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Affiliation(s)
- Adam R Meier
- Department of Chemistry , Bucknell University , 1 Dent Drive , Lewisburg , Pennsylvania 17837 , United States
| | - Jenna B Yehl
- Department of Chemistry , Bucknell University , 1 Dent Drive , Lewisburg , Pennsylvania 17837 , United States
| | - Kyle W Eckenroad
- Department of Chemistry , Bucknell University , 1 Dent Drive , Lewisburg , Pennsylvania 17837 , United States
| | - Gregory A Manley
- Department of Chemistry , Bucknell University , 1 Dent Drive , Lewisburg , Pennsylvania 17837 , United States
| | - Timothy G Strein
- Department of Chemistry , Bucknell University , 1 Dent Drive , Lewisburg , Pennsylvania 17837 , United States
| | - David Rovnyak
- Department of Chemistry , Bucknell University , 1 Dent Drive , Lewisburg , Pennsylvania 17837 , United States
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3
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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] [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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4
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Eckenroad KW, Manley GA, Yehl JB, Pirnie RT, Strein TG, Rovnyak D. An Edge Selection Mechanism for Chirally Selective Solubilization of Binaphthyl Atropisomeric Guests by Cholate and Deoxycholate Micelles. Chirality 2016; 28:525-33. [DOI: 10.1002/chir.22609] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/08/2016] [Accepted: 04/14/2016] [Indexed: 12/16/2022]
Affiliation(s)
- Kyle W. Eckenroad
- Department of Chemistry, Bucknell University; Lewisburg Pennsylvania USA
| | - Gregory A. Manley
- Department of Chemistry, Bucknell University; Lewisburg Pennsylvania USA
| | - Jenna B. Yehl
- Department of Chemistry, Bucknell University; Lewisburg Pennsylvania USA
| | - Ross T. Pirnie
- Department of Chemistry, Bucknell University; Lewisburg Pennsylvania USA
| | - Timothy G. Strein
- Department of Chemistry, Bucknell University; Lewisburg Pennsylvania USA
| | - David Rovnyak
- Department of Chemistry, Bucknell University; Lewisburg Pennsylvania USA
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5
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Cheng B, Kaifer AE. Electrochemistry of viologen dications in cholate media and competition between the cholate assemblies and the cucurbit[7]uril host. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2997-3002. [PMID: 25688521 DOI: 10.1021/la505005r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The cathodic voltammetric behavior of N,N'-dimethyl-4,4'-bipyridinium (methylviologen, MV(2+)), N,N'-dipropyl-4,4'-bipyridinium (propylviologen, PV(2+)), N,N'-dibutyl-4,4'-bipyridinium (butylviologen, BV(2+)), and N-heptyl-N'-ethyl-4,4'-bipyridinium (heptyl-ethylviologen, HEV(2+)) was investigated in aqueous solution containing variable concentrations of sodium cholate. In general, the presence of cholate was found to solubilize the more hydrophobic forms of the viologen probes. Among the three accessible viologen oxidation states (V(2+), V(+•), and V), the intermediate cation radical (V(+•)) was preferentially stabilized by the cholate aggregates regardless of the nature of the N-alkyl substituents. This stabilization leads to anodic shifts in the first half-wave potential (V(2+)/V(+•)) and cathodic shifts in the second half-wave potential (V(+•)/V) for viologen reduction. Both potential shifts were considerably more pronounced as the hydrophobic character of the viologen probe increased. The presence of the cucurbit[7]uril host in the solution leads to the formation of very stable inclusion complexes with the viologen probes, which tend to eliminate or substantially decrease the interactions between the viologens and the cholate micellar aggregates.
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Affiliation(s)
- Beijun Cheng
- Center for Supramolecular Science and Department of Chemistry, University of Miami, Coral Gables, Florida 33124-0431, United States
| | - Angel E Kaifer
- Center for Supramolecular Science and Department of Chemistry, University of Miami, Coral Gables, Florida 33124-0431, United States
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6
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Ganguly A, Ghosh S, Guchhait N. Modulated photophysics of an anthracene-based fluorophore within bile-salt aggregates: the effect of the ionic strength of the medium on the aggregation behavior. Photochem Photobiol Sci 2015; 14:2168-78. [DOI: 10.1039/c5pp00280j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Binding interactions of an anthracene-based fluorescent probe with a series of bile-salt aggregates of varying hydrophobicity, as well as salt induced alterations of the binding behavior have been thoroughly demonstrated.
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Affiliation(s)
| | - Soumen Ghosh
- Department of Chemistry
- University of Calcutta
- Calcutta-700009
- India
| | - Nikhil Guchhait
- Department of Chemistry
- University of Calcutta
- Calcutta-700009
- India
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7
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Agnihotri H, Vasu AK, Palakollu V, Kanvah S. Neutral and cationic pyridylbutadienes: solvatochromism and fluorescence response with sodium cholate. Photochem Photobiol Sci 2015; 14:2159-67. [DOI: 10.1039/c5pp00179j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Characteristic ICT emission in solvents and enhanced emission intensity in presence of sodium cholate.
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Affiliation(s)
- Harsha Agnihotri
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
| | - Anuji K. Vasu
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
| | | | - Sriram Kanvah
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
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8
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Santos CS, Miller AC, Pace TCS, Morimitsu K, Bohne C. Photochromism of a spiropyran and a diarylethene in bile salt aggregates in aqueous solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11319-11328. [PMID: 25203491 DOI: 10.1021/la503164e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Bile salt aggregates incorporate aqueous-insoluble photochromic compounds. The photochromism of a spiropyran (1, 1',3',3'-trimethyl-6-nitrospiro[2H-1]-benzopyran-2,2'-indoline) and a diarylethene derivative (2, 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene) was quantified in different bile salt aggregates. These aggregates act as efficient hosts to solubilize aqueous insoluble photochromic compounds where either both isomers are nonpolar, for example, 2, or compounds where one isomer is hydrophobic and the other is more polar, for example, 1. Methodology was developed to determine molar absorptivity coefficients for solutions containing both isomers and to determine the photoconversion quantum yields under continuous irradiation. The methods were validated by determining parameters in homogeneous solution, which were the same as previously reported. In the case of the colored isomer of 1, the molar extinction coefficient in ethanol at 537 nm ((3.68 ± 0.03) × 10(4) cm(-1) M(-1)) was determined with higher precision. The quantum yields for the photoconversion between the isomers of 2 were shown to be the same in cyclohexane and in the aggregates of sodium cholate (NaCh), deoxycholate (NaDC), and taurocholate (NaTC), showing that bile salt aggregates are not sufficiently rigid to affect the equilibrium between the two possible conformers of the colorless form. In contrast, for 1 the quantum yields for the conversion from the colorless to the colored isomer were higher in bile salts than in ethanol, and the quantum yield was highest in the more hydrophobic aggregates of NaDC, followed by NaCh and then NaTC. The structure of the bile salt had no effect on the quantum yield for the conversion of the colored to the colorless isomer of 1, but these values were higher than in ethanol. For all three bile salts, the absorption maximum for the colored form of 1 suggested that this isomer was located in an environment that is more polar than ethanol.
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Affiliation(s)
- Cerize S Santos
- Department of Chemistry, University of Victoria , P.O. Box 3065, Victoria, BC V8W 3V6, Canada
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9
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Gomez-Mendoza M, Marin ML, Miranda MA. Two-channel dansyl/tryptophan emitters with a cholic acid bridge as reporters for local hydrophobicity within supramolecular systems based on bile salts. Org Biomol Chem 2014; 12:8499-504. [DOI: 10.1039/c4ob01394h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Simultaneous emission from the Trp and Dns fluorophores of linked dyads in biomimetic media is quenched by iodide anions with rate constants that depend on the local hydrophobicity.
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Affiliation(s)
- M. Gomez-Mendoza
- Instituto Universitario Mixto de Tecnología Química (UPV-CSIC)
- Universitat Politècnica de València
- 46022 Valencia, Spain
| | - M. Luisa Marin
- Instituto Universitario Mixto de Tecnología Química (UPV-CSIC)
- Universitat Politècnica de València
- 46022 Valencia, Spain
| | - Miguel A. Miranda
- Instituto Universitario Mixto de Tecnología Química (UPV-CSIC)
- Universitat Politècnica de València
- 46022 Valencia, Spain
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10
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Mandal S, Ghosh S, Banerjee C, Rao VG, Sarkar N. Modulation of Photophysics and Photodynamics of 1′-Hydroxy-2′-acetonaphthone (HAN) in Bile Salt Aggregates: A Study of Polarity and Nanoconfinement Effects. J Phys Chem B 2012; 116:8780-92. [DOI: 10.1021/jp302435h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Sarthak Mandal
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Surajit Ghosh
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Chiranjib Banerjee
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Vishal Govind Rao
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India
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11
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Eising R, Felippe AC, Domingos JB. Physicochemical Investigation of the Association of the Biosurfactants Sodium Cholate and Sodium Dodecanoate With Poly(ethyleneoxide). J DISPER SCI TECHNOL 2012. [DOI: 10.1080/01932691.2010.530094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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12
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Moribe K, Masaki M, Kinoshita R, Zhang J, Limwikrant W, Higashi K, Tozuka Y, Oguchi T, Yamamoto K. Guest molecular size-dependent inclusion complexation of parabens with cholic acid by cogrinding. Int J Pharm 2011; 420:191-7. [DOI: 10.1016/j.ijpharm.2011.08.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 08/02/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
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13
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Wang Y, Wang X, Zhang Y. Enhancement of Palladium‐Porphyrin Room Temperature Phosphorescence by Alkaline Earth Metal in Deoxycholate Aggregates Solution. Photochem Photobiol 2011; 87:772-8. [DOI: 10.1111/j.1751-1097.2011.00927.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ying‐Te Wang
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan, China
| | - Xiang‐Wei Wang
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan, China
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14
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Baldridge A, Amador A, Tolbert LM. Fluorescence turn on by cholate aggregates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:3271-3274. [PMID: 21395254 DOI: 10.1021/la2003244] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Bile salts, including sodium cholate (NaCh), are amphiphilic molecules with a concave hydrophilic side and a convex hydrophobic side. By forming aggregates in aqueous solution, these natural surfactants fulfill vital biological roles in the solubilization of cholesterol, lipids, and fat-soluble vitamins and thus are involved in the transport and absorption of important biological molecules. Following our success with the encapsulation of fluorescent protein chromophore (FP) analogs by synthetic hydrophobic and hydrophilic hosts, based upon substitution patterns, we now report the binding and turn on of other analogs by bile salt aggregates, observations which may lead to new tools for studying trafficking in these important systems.
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Affiliation(s)
- Anthony Baldridge
- School of Chemistry and Biochemistry, 901 Atlantic Drive, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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15
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Pace TCS, Souza Júnior SP, Zhang HT, Bohne C. Effect of terbium(iii) on the binding of aromatic guests with sodium taurocholate aggregates. Photochem Photobiol Sci 2011; 10:1568-77. [DOI: 10.1039/c1pp05130j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Fuentealba D, Thurber K, Bovero E, Pace TCS, Bohne C. Effect of sodium chloride on the binding of polyaromatic hydrocarbon guests with sodium cholate aggregates. Photochem Photobiol Sci 2011; 10:1420-30. [DOI: 10.1039/c1pp05058c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Cuquerella MC, Rohacova J, Marin ML, Miranda MA. Stereodifferentiation in fluorescence quenching within cholic acid aggregates. Chem Commun (Camb) 2010; 46:4965-7. [DOI: 10.1039/c0cc00176g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Li R, Carpentier E, Newell ED, Olague LM, Heafey E, Yihwa C, Bohne C. Effect of the structure of bile salt aggregates on the binding of aromatic guests and the accessibility of anions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13800-13808. [PMID: 19606836 DOI: 10.1021/la901826y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The binding of naphthalene (Np), 1-ethylnaphthalene (EtNp), acenaphthene (AcN), and 1-naphthyl-1-ethanol (NpOH) as guests to the aggregates of sodium cholate (NaCh), taurocholate (NaTC), deoxycholate (NaDC), and deoxytaurocholate (NaTDC) was studied with the objective of determining how the structure of the bile salts affects the binding dynamics of guests and quenchers with the bile salt aggregates. Time-resolved and steady-state fluorescence experiments were used to determine the binding efficiency of the guests with the aggregates and were also employed to investigate the quenching of the singlet excited state of the guests by iodide anions. Quenching studies of the triplet excited states using laser flash photolysis were employed to determine the accessibility to the aggregate of nitrite anions, used as quenchers, and the dissociation rate constants of the guests from the bile salt aggregates. The binding efficiency of the guests to NaDC and NaTDC is higher than for NaCh and NaTC, and the protection efficiency is also higher for NaDC and NaTDC, in line with the larger aggregates formed for the latter bile salts. The formation of aggregates is in part driven by the structure of the guest, where an increased protection efficiency and residence time can be achieved by the introduction of short alkyl substituents (AcN or EtNp vs Np). NpOH was shown to be located in a very different environment in all four bile salts when compared to AcN, EtNp, and Np, suggesting that hydrogen bonding plays an important role in the formation of the aggregate around NpOH.
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Affiliation(s)
- Rui Li
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3 V6, Canada
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Amundson LL, Li R, Bohne C. Effect of the guest size and shape on its binding dynamics with sodium cholate aggregates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8491-500. [PMID: 18637697 DOI: 10.1021/la800439m] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The binding dynamics of the guests acenaphthene, phenanthrene, fluorene, and acenaphthenol with sodium cholate aggregates were studied using laser flash photolysis and fluorescence. The location of the guests in the bile salt aggregate is determined by the guest's hydrophobicity, where acenaphthene, phenanthrene, and fluorene bind to the primary aggregates, while acenaphthenol binds to the secondary bile salt aggregates. The residence time of the guests in the primary aggregates and the access of ionic species from the aqueous phase to the guest in the aggregate depend on the size and the shape of the guest. These results show that bile salt aggregates are adaptable supramolecular host systems.
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Affiliation(s)
- Laurie L Amundson
- Department of Chemistry, University of Victoria, PO Box 3065, Victoria, BC, Canada
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Mandal U, Ghosh S, Das DK, Adhikari A, Dey S, Bhattacharyya K. Ultrafast fluorescence resonance energy transfer in a bile salt aggregate: Excitation wavelength dependence. J CHEM SCI 2008. [DOI: 10.1007/s12039-008-0003-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Adhikari A, Dey S, Mandal U, Das DK, Ghosh S, Bhattacharyya K. Femtosecond Solvation Dynamics in Different Regions of a Bile Salt Aggregate: Excitation Wavelength Dependence. J Phys Chem B 2008; 112:3575-80. [DOI: 10.1021/jp7106445] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Aniruddha Adhikari
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Shantanu Dey
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Ujjwal Mandal
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Dibyendu Kumar Das
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Subhadip Ghosh
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Kankan Bhattacharyya
- Physical Chemistry Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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Zhang HM, Wang Y, Jin WJ. Study on the kinetic properties of phosphor in deoxycholate aggregates by phosphorescent quenching methodology. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 88:36-42. [PMID: 17570675 DOI: 10.1016/j.jphotobiol.2007.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 02/17/2007] [Accepted: 04/30/2007] [Indexed: 11/20/2022]
Abstract
Owing to the unique molecular structure and aggregate behaviors in aqueous solution, dihydroxy bile salts can provide phosphorescent probe with a special microenvironment in which the room temperature phosphorescence of probe can be detected in the presence of dissolved oxygen. It, however, is not very clear how the bile salts work in inducing this kind of oxygen-independent phosphorescence. The present work tries to offer with possible more insights by investigating the particular kinetic behaviors of 3-bromoquinoline (3-BrQ) as probe in sodium deoxycholate (NaDC) aggregate based on phosphorescent quenching methodology. The critical aggregate concentration of NaDC is estimated as about 0.5mM based on the enhancement of probe phosphorescence. As the functions of quencher Cu(2+) and NO(2)(-), the rate constants of various photophysical processes for 3-BrQ are obtained in NaDC solution and full aqueous solution, respectively. In NaDC solution, the quenching rate constant k(cu2+) equals to 1.77x10(7)M(-1)s(-1) k(no-2)(mq) 1.62x10(6)M(-1)s(-1). The exit rate k(-) and entrance rate k(+) are determined to be 16-46s(-1) and 10(6)M(-1)s(-1) levels, respectively. The quenching rate constant k(o2)(q) of dissolved oxygen is estimated as 4.15x10(4)M(-1)s(-1) in air-saturated NaDC solution at 1atm.
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Affiliation(s)
- Hong-Mei Zhang
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, PR China
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Yihwa C, Bohne C. Effect of Solvent Polarity and Viscosity on the Guest Binding Dynamics with Bile Salt Aggregates†. Photochem Photobiol 2007; 83:494-502. [PMID: 17115797 DOI: 10.1562/2006-09-17-ra-1043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bile salts form supramolecular aggregates with two binding sites with different properties. The guest binding dynamics to the aggregates and guest protection from species in the aqueous phase were investigated using fluorescence and laser flash photolysis experiments. Sodium cholate, deoxycholate and taurodeoxycholate were used as bile salts and acetonitrile or ethylene glycol were added as co-solvents to water in order to alter the binding properties of 1-ethylnaphthalene and 1-naphthyl-1-ethanol with the aggregates. The binding dynamics are faster and protection efficiencies are lower for guests bound to cholate and in the presence of either co-solvent.
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Affiliation(s)
- Chang Yihwa
- Department of Chemistry, University of Victoria, Victoria, BC, Canada
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Megyesi M, Biczók L. Berberine Alkaloid as a Sensitive Fluorescent Probe for Bile Salt Aggregates. J Phys Chem B 2007; 111:5635-9. [PMID: 17474769 DOI: 10.1021/jp067702g] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Effect of sodium cholate (NaC) bile salt on the absorption and fluorescence properties of berberine cation was studied in aqueous solution and water-cosolvent mixtures. The alteration of the fluorescent behavior with increasing NaC concentration showed an entirely different trend from that found previously in the presence of sodium dodecylsulfate. Binding to bile salt agglomerates led to significant fluorescence intensity enhancement, and the fluorescence lifetime of berberine proved to be highly sensitive to the structure and size of the aggregates. The dual exponential decay kinetics above 10 mM NaC concentration showed that the probe resided in two totally different binding sites. At 2-10 mM NaC concentrations, only primary aggregates were detected. The aggregate disrupting power of cosolvents decreased in the series of dimethylformamide, acetonitrile, formamide, and methanol. These compounds enhanced the water accessibility of berberine bound to aggregates and diminished the number of secondary aggregates.
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Affiliation(s)
- Mónika Megyesi
- Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary
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