TY - JOUR
T1 - Unusual phosphatidylcholine lipid phase behavior in the ionic liquid ethylammonium nitrate
AU - Salvati Manni, Livia
AU - Davies, Caitlin
AU - Wood, Kathleen
AU - Assenza, Salvatore
AU - Atkin, Rob
AU - Warr, Gregory G.
N1 - Funding Information:
This work was funded by a Discovery Grant from the Australian Research Council (DP200102248). The authors acknowledge the free use of SasView ( http://www.sasview.org/ ), developed under the NSF award DMR-0520547, SINE2020 project, grant agreement No 654000. The authors acknowledge Sydney Analytical for access to the SAXS instrument, and Paul A. FitzGerald for his experimental assistance. L.S.M. acknowledge the Swiss National Foundation of Science for financial support grant no. P2ZHP2_187769. The authors thank the Australian Nuclear Science and Technology Organization (ANSTO, P9710) for beam line access on Quokka.
Publisher Copyright:
© 2023 The Author(s)
PY - 2023/8
Y1 - 2023/8
N2 - Hypothesis: The forces that govern lipid self-assembly ionic liquids are similar to water, but their different balance can result in unexpected behaviour. Experiments: The self-assembly behaviour and phase equilibria of two phospholipids, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in the most common protic ionic liquid, ethylammonium nitrate (EAN) have been investigated as function of composition and temperature by small- and wide-angle X-ray scattering (SAXS/WAXS) and small-angle neutron scattering (SANS). Findings: Both lipids form unusual self-assembly structures and show complex and unexpected phase behaviour unlike that seen in water; DSPC undergoes a gel Lβ to crystalline Lc phase transition on warming, while POPC forms worm-like micelles L1 upon dilution. This surprising phase behaviour is attributed to the large size of the EAN ions that solvate the lipid headgroup compared to water changing amphiphile packing. Weaker H-bonding between EAN and lipid headgroups also contributes. These results provide new insight for the design of lipid based nanostructured materials in ionic liquids with atypical properties.
AB - Hypothesis: The forces that govern lipid self-assembly ionic liquids are similar to water, but their different balance can result in unexpected behaviour. Experiments: The self-assembly behaviour and phase equilibria of two phospholipids, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in the most common protic ionic liquid, ethylammonium nitrate (EAN) have been investigated as function of composition and temperature by small- and wide-angle X-ray scattering (SAXS/WAXS) and small-angle neutron scattering (SANS). Findings: Both lipids form unusual self-assembly structures and show complex and unexpected phase behaviour unlike that seen in water; DSPC undergoes a gel Lβ to crystalline Lc phase transition on warming, while POPC forms worm-like micelles L1 upon dilution. This surprising phase behaviour is attributed to the large size of the EAN ions that solvate the lipid headgroup compared to water changing amphiphile packing. Weaker H-bonding between EAN and lipid headgroups also contributes. These results provide new insight for the design of lipid based nanostructured materials in ionic liquids with atypical properties.
KW - Ionic liquids
KW - LIPID self-assembly
KW - Phospholipids
KW - Small angle neutron scattering
KW - Small angle X-ray scattering
UR - http://www.scopus.com/inward/record.url?scp=85152418466&partnerID=8YFLogxK
U2 - 10.1016/j.jcis.2023.03.161
DO - 10.1016/j.jcis.2023.03.161
M3 - Article
C2 - 37068361
AN - SCOPUS:85152418466
SN - 0021-9797
VL - 643
SP - 276
EP - 281
JO - Journal of Colloid and Interface Science
JF - Journal of Colloid and Interface Science
ER -