Phase behavior of DOPE/TritonX100 (reduced) in dilute aqueous solution: aggregate structure and pH-dependence
(2004) In Colloids and Surfaces B: Biointerfaces 34(2). p.69-76- Abstract
- The phase behavior of dilute mixtures of dioleoylphosphatidylethanolamine (DOPE) and reduced TritonX100 (TX100(r)) has been investigated at pH 7.4 and 10. Using simple turbidity measurements and optical observations, together with cryo-transmission electron microscopy (cryo-TEM), we estimate the phase boundaries. We show that at both pH 7.4 and 10, a very large amount of surfactant is needed for the onset of micelle formation (X-TX100(r) similar to 0.60-0.70) as well as for a complete solubilization of DOPE into mixed micelles (X-TX100(r) > 0.94). We find that the micelles that are formed at high TX100(r) concentrations are of spherical shape. Increasing the pH from 7.4 to 10 has a comparably small effect on the transition from a... (More)
- The phase behavior of dilute mixtures of dioleoylphosphatidylethanolamine (DOPE) and reduced TritonX100 (TX100(r)) has been investigated at pH 7.4 and 10. Using simple turbidity measurements and optical observations, together with cryo-transmission electron microscopy (cryo-TEM), we estimate the phase boundaries. We show that at both pH 7.4 and 10, a very large amount of surfactant is needed for the onset of micelle formation (X-TX100(r) similar to 0.60-0.70) as well as for a complete solubilization of DOPE into mixed micelles (X-TX100(r) > 0.94). We find that the micelles that are formed at high TX100(r) concentrations are of spherical shape. Increasing the pH from 7.4 to 10 has a comparably small effect on the transition from a lamellar (L-alpha) to a micellar (L-1) phase. However, the reversed hexagonal phase (H-II) that is present at low surfactant content at pH 7.4 is absent at pH 10. This is due to the partial negative charge of DOPE at pH 10. We determine the fraction of charged DOPE (alpha = 0.34) at pH 10 in a 150 mM NaCl buffer using zeta-potential (zeta-potential) measurements in combination with a Poisson-Boltzmann (PB) model. The intrinsic pK(a) of the primary amino group of DOPE, in a pure DOPE membrane, is estimated to 9.15 +/- 0.2. (C) 2003 Elsevier B.V. All rights reserved. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/154094
- author
- Johnsson, Markus LU and Bergstrand, Nill
- organization
- publishing date
- 2004
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Liposome zeta-potential, Solubilization, Lipid, Surfactant, Intrinsic liposomal pKa
- in
- Colloids and Surfaces B: Biointerfaces
- volume
- 34
- issue
- 2
- pages
- 69 - 76
- publisher
- Elsevier
- external identifiers
-
- pmid:15261076
- wos:000220271800001
- scopus:1442350555
- ISSN
- 1873-4367
- DOI
- 10.1016/j.colsurfb.2003.11.006
- language
- English
- LU publication?
- yes
- id
- fa5606e3-4384-41fe-8222-319e041bff09 (old id 154094)
- date added to LUP
- 2016-04-01 15:59:20
- date last changed
- 2022-01-28 08:33:18
@article{fa5606e3-4384-41fe-8222-319e041bff09,
abstract = {{The phase behavior of dilute mixtures of dioleoylphosphatidylethanolamine (DOPE) and reduced TritonX100 (TX100(r)) has been investigated at pH 7.4 and 10. Using simple turbidity measurements and optical observations, together with cryo-transmission electron microscopy (cryo-TEM), we estimate the phase boundaries. We show that at both pH 7.4 and 10, a very large amount of surfactant is needed for the onset of micelle formation (X-TX100(r) similar to 0.60-0.70) as well as for a complete solubilization of DOPE into mixed micelles (X-TX100(r) > 0.94). We find that the micelles that are formed at high TX100(r) concentrations are of spherical shape. Increasing the pH from 7.4 to 10 has a comparably small effect on the transition from a lamellar (L-alpha) to a micellar (L-1) phase. However, the reversed hexagonal phase (H-II) that is present at low surfactant content at pH 7.4 is absent at pH 10. This is due to the partial negative charge of DOPE at pH 10. We determine the fraction of charged DOPE (alpha = 0.34) at pH 10 in a 150 mM NaCl buffer using zeta-potential (zeta-potential) measurements in combination with a Poisson-Boltzmann (PB) model. The intrinsic pK(a) of the primary amino group of DOPE, in a pure DOPE membrane, is estimated to 9.15 +/- 0.2. (C) 2003 Elsevier B.V. All rights reserved.}},
author = {{Johnsson, Markus and Bergstrand, Nill}},
issn = {{1873-4367}},
keywords = {{Liposome zeta-potential; Solubilization; Lipid; Surfactant; Intrinsic liposomal pKa}},
language = {{eng}},
number = {{2}},
pages = {{69--76}},
publisher = {{Elsevier}},
series = {{Colloids and Surfaces B: Biointerfaces}},
title = {{Phase behavior of DOPE/TritonX100 (reduced) in dilute aqueous solution: aggregate structure and pH-dependence}},
url = {{http://dx.doi.org/10.1016/j.colsurfb.2003.11.006}},
doi = {{10.1016/j.colsurfb.2003.11.006}},
volume = {{34}},
year = {{2004}},
}