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Speer D, Salvador-Castell M, Huang Y, Liu GY, Sinha SK, Parikh AN. Surfactant-Mediated Structural Modulations to Planar, Amphiphilic Multilamellar Stacks. J Phys Chem B 2023; 127:7497-7508. [PMID: 37584633 PMCID: PMC10476200 DOI: 10.1021/acs.jpcb.3c01654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 08/01/2023] [Indexed: 08/17/2023]
Abstract
The hydrophobic effect, a ubiquitous process in biology, is a primary thermodynamic driver of amphiphilic self-assembly. It leads to the formation of unique morphologies including two highly important classes of lamellar and micellar mesophases. The interactions between these two types of structures and their involved components have garnered significant interest because of their importance in key biochemical technologies related to the isolation, purification, and reconstitution of membrane proteins. This work investigates the structural organization of mixtures of the lamellar-forming phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and two zwitterionic micelle-forming surfactants, being n-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (Zwittergent 3-12 or DDAPS) and 1-oleoyl-2-hydroxy-sn-glycero-3-phosphocholine (O-Lyso-PC), when assembled by water vapor hydration with X-ray diffraction measurements, brightfield optical microscopy, wide-field fluorescence microscopy, and atomic force microscopy. The results reveal that multilamellar mesophases of these mixtures can be assembled across a wide range of POPC to surfactant (POPC:surfactant) concentration ratios, including ratios far surpassing the classical detergent-saturation limit of POPC bilayers without significant morphological disruptions to the lamellar motif. The mixed mesophases generally decreased in lamellar spacing (D) and headgroup-to-headgroup distance (Dhh) with a higher concentration of the doped surfactant, but trends in water layer thickness (Dw) between each bilayer in the stack are highly variable. Further structural characteristics including mesophase topography, bilayer thickness, and lamellar rupture force were revealed by atomic force microscopy (AFM), exhibiting homogeneous multilamellar stacks with no significant physical differences with changes in the surfactant concentration within the mesophases. Taken together, the outcomes present the assembly of unanticipated and highly unique mixed mesophases with varied structural trends from the involved surfactant and lipidic components. Modulations in their structural properties can be attributed to the surfactant's chemical specificity in relation to POPC, such as the headgroup hydration and the hydrophobic chain tail mismatch. Taken together, our results illustrate how specific chemical complexities of surfactant-lipid interactions can alter the morphologies of mixed mesophases and thereby alter the kinetic pathways by which surfactants dissolve lipid mesophases in bulk aqueous solutions.
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Affiliation(s)
- Daniel
J. Speer
- Chemistry
Graduate Group, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
| | - Marta Salvador-Castell
- Department
of Physics, University of California, San
Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Yuqi Huang
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
| | - Gang-Yu Liu
- Department
of Chemistry, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
| | - Sunil K. Sinha
- Department
of Physics, University of California, San
Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Atul N. Parikh
- Chemistry
Graduate Group, University of California,
Davis, One Shields Avenue, Davis, California 95616, United States
- Department
of Biomedical Engineering, University of
California, Davis, One
Shields Avenue, Davis, California 95616, United States
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Gupta R, Singh A, Srihari V, Ghosh SK. Ionic Liquid-Induced Phase-Separated Domains in Lipid Multilayers Probed by X-ray Scattering Studies. ACS OMEGA 2021; 6:4977-4987. [PMID: 33644605 PMCID: PMC7905935 DOI: 10.1021/acsomega.0c06014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/28/2021] [Indexed: 05/16/2023]
Abstract
A cellular membrane, primarily a lipid bilayer, surrounds the internal components of a biological cell from the external components. This self-assembled bilayer is known to be perturbed by ionic liquids (ILs) causing malfunctioning of a cellular organism. In the present study, surface-sensitive X-ray scattering techniques have been employed to understand this structural perturbation in a lipid multilayer system formed by a zwitterionic phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine. The ammonium and phosphonium-based ILs with methanesulfonate anions are observed to induce phase-separated domains in the plane of a bilayer. The lamellar X-ray diffraction peaks suggest these domains to correlate across the bilayers in a smectic liquid crystalline phase. This induced IL-rich lamellar phase has a very low lamellar repeat distance, suggesting the formation of an interdigitated bilayer. The IL-poor phase closely related to the pristine lipid phase shows a decrement in the in-plane chain lattice parameters with a reduced tilt angle. The ammonium and phosphonium-based ILs with a relatively bulky anion, p-toluenemethanesulfonate, have shown a similar effect.
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Affiliation(s)
- Ritika Gupta
- Department
of Physics, School of Natural Sciences, Shiv Nadar University, NH 92, Tehsil Dadri, G. B. Nagar, Uttar Pradesh 201314, India
| | - Arnab Singh
- Surface
Physics and Material Science Division, Saha
Institute of Nuclear Physics, AF Block, Bidhannagar, Kolkata 700064, India
| | - Velaga Srihari
- High
Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Sajal K. Ghosh
- Department
of Physics, School of Natural Sciences, Shiv Nadar University, NH 92, Tehsil Dadri, G. B. Nagar, Uttar Pradesh 201314, India
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