Self-assembly of choline-based surface-active ionic liquids and concentration-dependent enhancement in the enzymatic activity of cellulase in aqueous medium
The micellization of choline-based anionic surface-active ionic liquids (SAILs) having lauroyl sarcosinate [Sar] − , dodecylsulfate [DS] − , and deoxycholate [Doc] − as counter-ions was investigated in an aqueous medium. Density functional theory (DFT) was employed to investigate the net interaction...
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Published in | Physical chemistry chemical physics : PCCP Vol. 26; no. 22; pp. 16218 - 16233 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
06.06.2024
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Subjects | |
Online Access | Get full text |
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Summary: | The micellization of choline-based anionic surface-active ionic liquids (SAILs) having lauroyl sarcosinate [Sar]
−
, dodecylsulfate [DS]
−
, and deoxycholate [Doc]
−
as counter-ions was investigated in an aqueous medium. Density functional theory (DFT) was employed to investigate the net interactional energy (
E
net
), extent of non-covalent interactions, and band gap of the choline-based SAILs. The critical micelle concentration (cmc) along with various parameters related to the surface adsorption, counter-ion binding (
β
), and polarity of the cores of the micelles were deduced employing surface tension measurements, conductometric titrations and fluorescence spectroscopy, respectively. A dynamic light scattering (DLS) system equipped with zeta-potential measurement set-up and small-angle neutron scattering (SANS) were used to predict the size, zeta-potential, and morphology, respectively, of the formed micelles. Thermodynamic parameters such as standard Gibb's free energy
and standard enthalpy
change of micellization were calculated using isothermal titration calorimetry (ITC). Upon comparing with sodium salt analogues, it was established that the micellization was predominantly governed by the extent of hydration of [Cho]
+
, the head groups of the respective anions, and the degree of counter-ion binding (
β
). Considering the concentration dependence of the enzyme-SAIL interactions, aqueous solutions of the synthesized SAILs at two different concentrations (below and above the cmc) were utilized as the medium for testing the enzymatic activity of cellulase. The activity of cellulase was found to be ∼7- to ∼13-fold higher compared to that observed in buffers in monomeric solutions of the SAILs and followed the order: [Cho][Sar] > [Cho][DS] > [Cho][Doc]. In the micellar solution, a ∼4- to 5-fold increase in enzymatic activity was observed.
Self-assembly of choline-based SAILs was investigated. The enzymatic activity of cellulase in aqueous solutions of the SAILs was found to be 4- to 13-fold higher compared to that observed in buffer depending on the type and concentration of the SAIL. |
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Bibliography: | Electronic supplementary information (ESI) available. See DOI https://doi.org/10.1039/d4cp01236d ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1463-9076 1463-9084 |
DOI: | 10.1039/d4cp01236d |