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Title: Electrostatic shape control of a charged molecular membrane from ribbon to scroll

Abstract

Bilayers of amphiphiles can organize into spherical vesicles, nanotubes, planar, undulating, and helical nanoribbons, and scroll-like cochleates. These bilayer-related architectures interconvert under suitable conditions. Here, a charged, chiral amphiphile (palmitoyl-lysine, C 16 -K 1 ) is used to elucidate the pathway for planar nanoribbon to cochleate transition induced by salt (NaCl) concentration. In situ small- and wide-angle X-ray scattering (SAXS/WAXS), atomic force and cryogenic transmission electron microscopies (AFM and cryo-TEM) tracked these transformations over angstrom to micrometer length scales. AFM reveals that the large length (L) to width (W) ratio nanoribbons (L/W > 10) convert to sheets (L/W → 1) before rolling into cochleates. A theoretical model based on electrostatic and surface energies shows that the nanoribbons convert to sheets via a first-order transition, at a critical Debye length, with 2 shallow minima of the order of thermal energy at L/W >> 1 and at L/W = 1. SAXS shows that interbilayer spacing ( D ) in the cochleates scales linearly with the Debye length, and ranges from 13 to 35 nm for NaCl concentrations from 100 to 5 mM. Theoretical arguments that include electrostatic and elastic energies explain the membrane rolling and the bilayer separation–Debye length relationship. These modelsmore » suggest that the salt-induced ribbon to cochleate transition should be common to all charged bilayers possessing an intrinsic curvature, which in the present case originates from molecular chirality. Our studies show how electrostatic interactions can be tuned to attain and control cochleate structures, which have potential for encapsulating, and releasing macromolecules in a size-selective manner.« less

Authors:
; ; ; ; ; ORCiD logo; ORCiD logo
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1570475
Grant/Contract Number:  
FG02-08ER46539
Resource Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 116 Journal Issue: 44; Journal ID: ISSN 0027-8424
Publisher:
Proceedings of the National Academy of Sciences
Country of Publication:
United States
Language:
English

Citation Formats

Gao, Changrui, Kewalramani, Sumit, Valencia, Dulce Maria, Li, Honghao, McCourt, Joseph M., Olvera de la Cruz, Monica, and Bedzyk, Michael J. Electrostatic shape control of a charged molecular membrane from ribbon to scroll. United States: N. p., 2019. Web. doi:10.1073/pnas.1913632116.
Gao, Changrui, Kewalramani, Sumit, Valencia, Dulce Maria, Li, Honghao, McCourt, Joseph M., Olvera de la Cruz, Monica, & Bedzyk, Michael J. Electrostatic shape control of a charged molecular membrane from ribbon to scroll. United States. doi:10.1073/pnas.1913632116.
Gao, Changrui, Kewalramani, Sumit, Valencia, Dulce Maria, Li, Honghao, McCourt, Joseph M., Olvera de la Cruz, Monica, and Bedzyk, Michael J. Mon . "Electrostatic shape control of a charged molecular membrane from ribbon to scroll". United States. doi:10.1073/pnas.1913632116.
@article{osti_1570475,
title = {Electrostatic shape control of a charged molecular membrane from ribbon to scroll},
author = {Gao, Changrui and Kewalramani, Sumit and Valencia, Dulce Maria and Li, Honghao and McCourt, Joseph M. and Olvera de la Cruz, Monica and Bedzyk, Michael J.},
abstractNote = {Bilayers of amphiphiles can organize into spherical vesicles, nanotubes, planar, undulating, and helical nanoribbons, and scroll-like cochleates. These bilayer-related architectures interconvert under suitable conditions. Here, a charged, chiral amphiphile (palmitoyl-lysine, C 16 -K 1 ) is used to elucidate the pathway for planar nanoribbon to cochleate transition induced by salt (NaCl) concentration. In situ small- and wide-angle X-ray scattering (SAXS/WAXS), atomic force and cryogenic transmission electron microscopies (AFM and cryo-TEM) tracked these transformations over angstrom to micrometer length scales. AFM reveals that the large length (L) to width (W) ratio nanoribbons (L/W > 10) convert to sheets (L/W → 1) before rolling into cochleates. A theoretical model based on electrostatic and surface energies shows that the nanoribbons convert to sheets via a first-order transition, at a critical Debye length, with 2 shallow minima of the order of thermal energy at L/W >> 1 and at L/W = 1. SAXS shows that interbilayer spacing ( D ) in the cochleates scales linearly with the Debye length, and ranges from 13 to 35 nm for NaCl concentrations from 100 to 5 mM. Theoretical arguments that include electrostatic and elastic energies explain the membrane rolling and the bilayer separation–Debye length relationship. These models suggest that the salt-induced ribbon to cochleate transition should be common to all charged bilayers possessing an intrinsic curvature, which in the present case originates from molecular chirality. Our studies show how electrostatic interactions can be tuned to attain and control cochleate structures, which have potential for encapsulating, and releasing macromolecules in a size-selective manner.},
doi = {10.1073/pnas.1913632116},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 44,
volume = 116,
place = {United States},
year = {2019},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1073/pnas.1913632116

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Works referenced in this record:

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