Combinatorial mixtures of organic solutes for improved liquid/liquid extraction of ions

Liu, Shu; Wei, An-Tsun; Wang, Hui; Van Winkle, David; Lenhert, Steven

doi:10.1039/d3sm00693j

Cited by 3 publications

(1 citation statement)

References 55 publications

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“…Phase separation in biological systems is crucial to the organization and function of biological molecules. For instance, the hydrophobic cores of lipid bilayers and lipid droplets can be thought of as a nonpolar organic phase in a cell, into which various lipids and lipophilic drugs tend to partition. − A variety of model systems, including oil–water two-phase systems, − lipid vesicles, , supported lipid bilayers, , and model lipid droplets, have been used to study these effects experimentally. Furthermore, lateral phase separation within lipid bilayers, also known as lipid rafts, can help to explain two-dimensional organization of molecules in biological membranes .…”

Section: Introductionmentioning

confidence: 99%

Kinetic Mechanism of Surfactant-Based Molecular Recognition: Selective Permeability across an Oil–Water Interface Regulated by Supramolecular Aggregates

Zhou,

Shiel,

Bell

et al. 2023

J. Phys. Chem. B

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Lipids are known to play a vital role in the molecular organization of all cellular life. Molecular recognition is another fundamental biological process that is generally attributed to biological polymers, such as proteins and nucleic acids. However, there is evidence that aggregates of lipids and lipid-like molecules are also capable of selectively binding to or regulating the partitioning of other molecules. We previously demonstrated that a model two-phase octanol/water system can selectively partition Red 40 and Blue 1 dyes added to an aqueous phase, with the selectivity depending on the surfactant (e.g., cetyltrimethylammonium bromide) dissolved in the organic phase. Here, we elucidate the mechanism of molecular recognition in this system by using quantitative partitioning experiments and molecular dynamics (MD) simulations. Our results indicate that the selectivity for the red dye is thermodynamically favored at all surfactant concentrations, while selectivity for the blue dye is kinetically favored at high surfactant concentrations. The kinetic selectivity for the blue dye correlates with the presence of molecular aggregation at the oil−water interface. Coarse-grained MD simulations elucidate nanoscale supramolecular structures that can preferentially bind one small molecule rather than another at an interface, providing a selectively permeable barrier in the absence of proteins. The results suggest a new supramolecular mechanism for molecular recognition with potential applications in drug delivery, drug discovery, and biosensing.

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Section: Introductionmentioning

confidence: 99%

Kinetic Mechanism of Surfactant-Based Molecular Recognition: Selective Permeability across an Oil–Water Interface Regulated by Supramolecular Aggregates

Zhou,

Shiel,

Bell

et al. 2023

J. Phys. Chem. B

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Improving Bayesian optimization via hierarchical variation modeling for combinatorial experiments given limited runs guided by process knowledge

Wei,

Liu,

Lenhert

et al. 2024

Knowledge-Based Systems

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Lipid-Based Catalysis Demonstrated by Bilayer-Enabled Ester Hydrolysis

Liu,

Kumar,

Bell

et al. 2024

Membranes

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Lipids have not traditionally been considered likely candidates for catalyzing reactions in biological systems. However, there is significant evidence that aggregates of amphiphilic compounds are capable of catalyzing reactions in synthetic organic chemistry. Here, we demonstrate the potential for the hydrophobic region of a lipid bilayer to provide an environment suitable for catalysis by means of a lipid aggregate capable of speeding up a chemical reaction. By bringing organic molecules into the nonpolar or hydrophobic region of a lipid bilayer, reactions can be catalyzed by individual or collections of small, nonpolar, or amphiphilic molecules. We demonstrate this concept by the ester hydrolysis of calcein-AM to produce a fluorescent product, which is a widely used assay for esterase activity in cells. The reaction was first carried out in a two-phase octanol–water system, with the organic phase containing the cationic amphiphiles cetyltrimethylammonium bromide (CTAB) or octadecylamine. The octanol phase was then replaced with phospholipid vesicles in water, where the reaction was also found to be carried out. The reaction was monitored using quantitative fluorescence, which revealed catalytic turnover numbers on a scale of 10−7 to 10−8 s−1 for each system, which is much slower than enzymatic catalysis. The reaction product was characterized by 1H-NMR measurements, which were consistent with ester hydrolysis. The implications of thinking about lipids and lipid aggregates as catalytic entities are discussed in the context of biochemistry, pharmacology, and synthetic biology.

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Combinatorial mixtures of organic solutes for improved liquid/liquid extraction of ions

Abstract: Bayesian optimization of organic solutes for improving liquid/liquid extraction of ions.

Cited by 3 publications

References 55 publications

Kinetic Mechanism of Surfactant-Based Molecular Recognition: Selective Permeability across an Oil–Water Interface Regulated by Supramolecular Aggregates

Kinetic Mechanism of Surfactant-Based Molecular Recognition: Selective Permeability across an Oil–Water Interface Regulated by Supramolecular Aggregates

Improving Bayesian optimization via hierarchical variation modeling for combinatorial experiments given limited runs guided by process knowledge

Lipid-Based Catalysis Demonstrated by Bilayer-Enabled Ester Hydrolysis

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