TY - JOUR

T1 - The interaction of styrene maleic acid copolymers with phospholipids in Langmuir monolayers, vesicles and nanodiscs

T2 - a structural study

AU - Hall, S.C.L.

AU - Tognoloni, C.

AU - Campbell, R.A.

AU - Richens, J.

AU - O'Shea, P.

AU - Terry, A.E.

AU - Price, G.J.

AU - Dafforn, T.R.

AU - Edler, K.J.

AU - Arnold, T.

N1 - Funding details: Engineering and Physical Sciences Research Council, EPSRC, EP/M506461/1 Funding details: Biotechnology and Biological Sciences Research Council, BBSRC, BB/M018261/1

PY - 2022/11/30

Y1 - 2022/11/30

N2 - HypothesisSelf-assembly of amphipathic styrene maleic acid copolymers with phospholipids in aqueous solution results in the formation of ‘nanodiscs’ containing a planar segment of phospholipid bilayer encapsulated by a polymer belt. Recently, studies have reported that lipids rapidly exchange between both nanodiscs in solution and external sources of lipids. Outstanding questions remain regarding details of polymer-lipid interactions, factors influencing lipid exchange and structural effects of such exchange processes. Here, the dynamic behaviour of nanodiscs is investigated, specifically the role of membrane charge and polymer chemistry.ExperimentsTwo model systems are investigated: fluorescently labelled phospholipid vesicles, and Langmuir monolayers of phospholipids. Using fluorescence spectroscopy and time-resolved neutron reflectometry, the membrane potential, monolayer structure and composition are monitored with respect to time upon polymer and nanodisc interactions.FindingsIn the presence of external lipids, polymer chains embed throughout lipid membranes, the extent of which is governed by the net membrane charge. Nanodiscs stabilised by three different polymers will all exchange lipids and polymer with monolayers to differing extents, related to the properties of the stabilising polymer belt. These results demonstrate the dynamic nature of nanodiscs which interact with the local environment and are likely to deposit both lipids and polymer at all stages of use.

AB - HypothesisSelf-assembly of amphipathic styrene maleic acid copolymers with phospholipids in aqueous solution results in the formation of ‘nanodiscs’ containing a planar segment of phospholipid bilayer encapsulated by a polymer belt. Recently, studies have reported that lipids rapidly exchange between both nanodiscs in solution and external sources of lipids. Outstanding questions remain regarding details of polymer-lipid interactions, factors influencing lipid exchange and structural effects of such exchange processes. Here, the dynamic behaviour of nanodiscs is investigated, specifically the role of membrane charge and polymer chemistry.ExperimentsTwo model systems are investigated: fluorescently labelled phospholipid vesicles, and Langmuir monolayers of phospholipids. Using fluorescence spectroscopy and time-resolved neutron reflectometry, the membrane potential, monolayer structure and composition are monitored with respect to time upon polymer and nanodisc interactions.FindingsIn the presence of external lipids, polymer chains embed throughout lipid membranes, the extent of which is governed by the net membrane charge. Nanodiscs stabilised by three different polymers will all exchange lipids and polymer with monolayers to differing extents, related to the properties of the stabilising polymer belt. These results demonstrate the dynamic nature of nanodiscs which interact with the local environment and are likely to deposit both lipids and polymer at all stages of use.

KW - Langmuir monolayer

KW - Neutron reflectometry

KW - Nanodisc

KW - Lipid Exchange

KW - Polymer

KW - Styrene Maleic Acid (SMA)

KW - Styrene Maleic Acid Lipid Particle (SMALP)

KW - Reversible, Addition−Fragmentation Chain-Transfer (RAFT)

KW - Adsorption

U2 - 10.1016/j.jcis.2022.03.102

DO - 10.1016/j.jcis.2022.03.102

M3 - Journal article

VL - 625

SP - 220

EP - 236

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 1095-7103

ER -