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Deal AM. Infrared Reflection Absorption Spectroscopy (IRRAS) of Water-Soluble Surfactants: Is it Surface-Specific? APPLIED SPECTROSCOPY 2023; 77:1280-1288. [PMID: 37743797 DOI: 10.1177/00037028231200903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Infrared reflection absorption spectroscopy (IRRAS) is commonly used to study the structure and chemistry of molecules residing at surfaces, including water surfaces, which has far-reaching applications including atmospheric chemistry and food science. However, there is some debate regarding the surface-specificity of IRRAS when examining soluble surfactants on aqueous solutions, and there is some evidence that the surface-specificity may differ between IRRAS of ionic surfactants and soluble organic acids. This paper presents infrared reflection absorption (IRRA) spectra of soluble organic acids underneath monolayers of insoluble surfactants, where the contributions from the insoluble surfactants are subtracted from the spectra to capture "subsurface effects". These "subsurface" spectra demonstrate that IRRA spectra of soluble organic acids are surface specific, and this observation is supported by a simplified model for reflections from "subsurface" layers. Finally, the observations presented here are compared to literature observations regarding the surface-specificity of IRRAS when studying ionic surfactants. Overall, this work demonstrates the utility of IRRAS for studying the structures and chemistry of soluble organic acids at aqueous surfaces.
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Affiliation(s)
- Alexandra M Deal
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
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Yang J, Liu Y, Liang X, Yang Y, Li Q. Enantio-, Regio-, and Chemoselective Lipase-Catalyzed Polymer Synthesis. Macromol Biosci 2018; 18:e1800131. [PMID: 29870576 DOI: 10.1002/mabi.201800131] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 04/30/2018] [Indexed: 12/19/2022]
Abstract
In contrast to chemical routes, enzymatic polymerization possesses favorable characteristics of mild reaction conditions, few by-products, and high activity toward cyclic lactones which make it a promising technique for constructing polymeric materials. Meanwhile, it can avoid the trace residue of metallic catalysts and potential toxicity, and thus exhibits great potential in the biomedical fields. More importantly, lipase-catalyzed polymer synthesis usually shows favorable enantio-, regio-, and chemoselectivity. Here, the history and recent developments in lipase-catalyzed selective polymerization for constructing polymers with unique structures and properties are highlighted. In particular, the synthesis of polymeric materials which are difficult to prepare in a chemical route and the construction of polymers through the combination of selective enzymatic and chemical methods are focused. In addition, the future direction is proposed especially based on the rapid developments in computational chemistry and protein engineering techniques.
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Affiliation(s)
- Jiebing Yang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Changchun, 130012, China
| | - Yong Liu
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Changchun, 130012, China
| | - Xiao Liang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Changchun, 130012, China
| | - Yan Yang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Changchun, 130012, China
| | - Quanshun Li
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Changchun, 130012, China
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Watanabe S, Ohta T, Urata R, Sato T, Takaishi K, Uchiyama M, Aoyama T, Kunitake M. Quasi-Phase Diagrams at Air/Oil Interfaces and Bulk Oil Phases for Crystallization of Small-Molecular Semiconductors by Adjusting Gibbs Adsorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8906-8913. [PMID: 28759233 DOI: 10.1021/acs.langmuir.7b01603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The temperature and concentration dependencies of the crystallization of two small-molecular semiconductors were clarified by constructing quasi-phase diagrams at air/oil interfaces and in bulk oil phases. A quinoidal quaterthiophene derivative with four alkyl chains (QQT(CN)4) in 1,1,2,2-tetrachroloethane (TCE) and a thienoacene derivative with two alkyl chains (C8-BTBT) in o-dichlorobenzene were used. The apparent crystal nucleation temperature (Tn) and dissolution temperature (Td) of the molecules were determined based on optical microscopy examination in closed glass capillaries and open dishes during slow cooling and heating processes, respectively. Tn and Td were considered estimates of the critical temperatures for nuclear formation and crystal growth, respectively. The Tn values of QQT(CN)4 and C8-BTBT at the air/oil interfaces were higher than those in the bulk oil phases, whereas the Td values at the air/oil interfaces were almost the same as those in the bulk oil phases. These Gibbs adsorption phenomena were attributed to the solvophobic effect of the alkyl chain moieties. The temperature range between Tn and Td corresponds to suitable supercooling conditions for ideal crystal growth based on the suppression of nucleation. The Tn values at the water/oil and oil/glass interfaces did not shift compared with those of the bulk phases, indicating that adsorption did not occur at the hydrophilic interfaces. Promotion and inhibition of nuclear formation for crystal growth of the semiconductors were achieved at the air/oil and hydrophilic interfaces, respectively.
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Affiliation(s)
- Satoshi Watanabe
- Department of Applied Chemistry and Biochemistry, Kumamoto University , 2-39-1 Kurokami, Chuou-ku, Kumamoto, Japan 860-8555
| | - Takahisa Ohta
- Department of Applied Chemistry and Biochemistry, Kumamoto University , 2-39-1 Kurokami, Chuou-ku, Kumamoto, Japan 860-8555
| | - Ryota Urata
- Department of Applied Chemistry and Biochemistry, Kumamoto University , 2-39-1 Kurokami, Chuou-ku, Kumamoto, Japan 860-8555
| | - Tetsuya Sato
- Department of Applied Chemistry and Biochemistry, Kumamoto University , 2-39-1 Kurokami, Chuou-ku, Kumamoto, Japan 860-8555
| | - Kazuto Takaishi
- Graduate School of Natural Science and Technology, Okayama University , Tsushimanaka 3-1-1, Kita-ku, Okayama City, Okayama, Japan 700-8530
| | - Masanobu Uchiyama
- Elements Chemistry Laboratory , RIKEN, 2-1 Hirosawa, Wako City, Saitama, Japan 351-0198
- Graduate School of Pharmaceutical Sciences, The University of Tokyo , Hongo 7-3-1, Bunkyou-ku, Tokyo, Japan 113-0033
| | - Tetsuya Aoyama
- Elements Chemistry Laboratory , RIKEN, 2-1 Hirosawa, Wako City, Saitama, Japan 351-0198
| | - Masashi Kunitake
- Department of Applied Chemistry and Biochemistry, Kumamoto University , 2-39-1 Kurokami, Chuou-ku, Kumamoto, Japan 860-8555
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Wang D, de Jong DH, Rühling A, Lesch V, Shimizu K, Wulff S, Heuer A, Glorius F, Galla HJ. Imidazolium-Based Lipid Analogues and Their Interaction with Phosphatidylcholine Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12579-12592. [PMID: 27934518 DOI: 10.1021/acs.langmuir.6b02496] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
4,5-Dialkylated imidazolium lipid salts are a new class of lipid analogues showing distinct biological activities. The potential effects of the imidazolium lipids on artificial lipid membranes and the corresponding membrane interactions was analyzed. Therefore, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was employed to create an established lipid monolayer model and a bilayer membrane. Mixed monolayers of DPPC and 4,5-dialkylimidazolium lipids differing by their alkyl chain length (C7, C11, and C15) were characterized by surface pressure-area (π-A) isotherms using a Wilhelmy film balance in combination with epifluorescence microscopy. Monolayer hysteresis for binary mixtures was examined by recording triplicate consecutive compression-expansion cycles. The lipid miscibility and membrane stability of DPPC/imidazolium lipids were subsequently evaluated by the excess mean molecular area (ΔAex) and the excess Gibbs free energy (ΔGex) of mixing. Furthermore, the thermotropic behavior of mixed liposomes of DPPC/imidazolium lipids was investigated by differential scanning calorimetry (DSC). The C15-imidazolium lipid (C15-IMe·HI) forms a thermodynamically favored and kinetically reversible Langmuir monolayer with DPPC and exhibits a rigidification effect on both DPPC monolayer and bilayer structures at low molar fractions (X ≤ 0.3). However, the incorporation of the C11-imidazolium lipid (C11-IMe·HI) causes the formation of an unstable and irreversible Langmuir-Gibbs monolayer with DPPC and disordered DPPC liposomes. The C7-imidazolium lipid (C7-IMe·HI) displays negligible membrane activity. To better understand these results on a molecular level, all-atom molecular dynamics (MD) simulations were performed. The simulations yield two opposing molecular mechanisms governing the different behavior of the three imidazolium lipids: a lateral ordering effect and a free volume/stretching effect. Overall, our study provides the first evidence that the membrane interaction of the C15 and C11 derivatives modulates the structural organization of lipid membranes. On the contrary, for the C7 derivative its membrane activity is too low to contribute to its earlier reported potent cytotoxicity.
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Affiliation(s)
- Da Wang
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Djurre H de Jong
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Andreas Rühling
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Volker Lesch
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Karina Shimizu
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Stephanie Wulff
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Andreas Heuer
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Frank Glorius
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Hans-Joachim Galla
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
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