Cargando…
A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture
Techniques that can probe nanometer length scales, such as small-angle neutron scattering (SANS), have become increasingly popular to detect phase separation in membranes. But to extract the phase composition and domain structure from the SANS traces, complementary information is needed. Here, we pr...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2023
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10051979/ https://www.ncbi.nlm.nih.gov/pubmed/36984710 http://dx.doi.org/10.3390/membranes13030323 |
_version_ | 1785015021873397760 |
---|---|
author | Krzyzanowski, Natalie Porcar, Lionel Perez-Salas, Ursula |
author_facet | Krzyzanowski, Natalie Porcar, Lionel Perez-Salas, Ursula |
author_sort | Krzyzanowski, Natalie |
collection | PubMed |
description | Techniques that can probe nanometer length scales, such as small-angle neutron scattering (SANS), have become increasingly popular to detect phase separation in membranes. But to extract the phase composition and domain structure from the SANS traces, complementary information is needed. Here, we present a SANS, calorimetry and densitometry study of a mixture of two saturated lipids that exhibits solidus–liquidus phase coexistence: 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC, tail-deuterated DPPC) and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). With calorimetry, we investigated the phase diagram for this system and found that the boundary traces for both multilamellar vesicles (MLVs) as well as 50 nm unilamellar vesicles overlap. Because the solidus boundary was mostly inaccessible by calorimetry, we investigated it by both SANS and molecular volume measurements for a 1:1 dDPPC:DLPC lipid mixture. From the temperature behavior of the molecular volume for the 1:1 dDPPC:DLPC mixture, as well as the individual molecular volume of each lipid species, we inferred that the liquidus phase consists of only fluid-state lipids while the solidus phase consists of lipids that are in gel-like states. Using this solidus–liquidus phase model, the SANS data were analyzed with an unrestricted shape model analysis software: MONSA. The resulting fits show irregular domains with dendrite-like features as those previously observed on giant unilamellar vesicles (GUVs). The surface pair correlation function describes a characteristic domain size for the minority phase that decreases with temperature, a behavior found to be consistent with a concomitant decrease in membrane mismatch between the liquidus and solidus phases. |
format | Online Article Text |
id | pubmed-10051979 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-100519792023-03-30 A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture Krzyzanowski, Natalie Porcar, Lionel Perez-Salas, Ursula Membranes (Basel) Article Techniques that can probe nanometer length scales, such as small-angle neutron scattering (SANS), have become increasingly popular to detect phase separation in membranes. But to extract the phase composition and domain structure from the SANS traces, complementary information is needed. Here, we present a SANS, calorimetry and densitometry study of a mixture of two saturated lipids that exhibits solidus–liquidus phase coexistence: 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC, tail-deuterated DPPC) and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). With calorimetry, we investigated the phase diagram for this system and found that the boundary traces for both multilamellar vesicles (MLVs) as well as 50 nm unilamellar vesicles overlap. Because the solidus boundary was mostly inaccessible by calorimetry, we investigated it by both SANS and molecular volume measurements for a 1:1 dDPPC:DLPC lipid mixture. From the temperature behavior of the molecular volume for the 1:1 dDPPC:DLPC mixture, as well as the individual molecular volume of each lipid species, we inferred that the liquidus phase consists of only fluid-state lipids while the solidus phase consists of lipids that are in gel-like states. Using this solidus–liquidus phase model, the SANS data were analyzed with an unrestricted shape model analysis software: MONSA. The resulting fits show irregular domains with dendrite-like features as those previously observed on giant unilamellar vesicles (GUVs). The surface pair correlation function describes a characteristic domain size for the minority phase that decreases with temperature, a behavior found to be consistent with a concomitant decrease in membrane mismatch between the liquidus and solidus phases. MDPI 2023-03-10 /pmc/articles/PMC10051979/ /pubmed/36984710 http://dx.doi.org/10.3390/membranes13030323 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Krzyzanowski, Natalie Porcar, Lionel Perez-Salas, Ursula A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture |
title | A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture |
title_full | A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture |
title_fullStr | A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture |
title_full_unstemmed | A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture |
title_short | A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture |
title_sort | small-angle neutron scattering, calorimetry and densitometry study to detect phase boundaries and nanoscale domain structure in a binary lipid mixture |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10051979/ https://www.ncbi.nlm.nih.gov/pubmed/36984710 http://dx.doi.org/10.3390/membranes13030323 |
work_keys_str_mv | AT krzyzanowskinatalie asmallangleneutronscatteringcalorimetryanddensitometrystudytodetectphaseboundariesandnanoscaledomainstructureinabinarylipidmixture AT porcarlionel asmallangleneutronscatteringcalorimetryanddensitometrystudytodetectphaseboundariesandnanoscaledomainstructureinabinarylipidmixture AT perezsalasursula asmallangleneutronscatteringcalorimetryanddensitometrystudytodetectphaseboundariesandnanoscaledomainstructureinabinarylipidmixture AT krzyzanowskinatalie smallangleneutronscatteringcalorimetryanddensitometrystudytodetectphaseboundariesandnanoscaledomainstructureinabinarylipidmixture AT porcarlionel smallangleneutronscatteringcalorimetryanddensitometrystudytodetectphaseboundariesandnanoscaledomainstructureinabinarylipidmixture AT perezsalasursula smallangleneutronscatteringcalorimetryanddensitometrystudytodetectphaseboundariesandnanoscaledomainstructureinabinarylipidmixture |