title: Tuning the size of styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) using RAFT polymerization for biophysical studies.
abstract: Characterization of membrane proteins is challenging due to the difficulty in mimicking the native lipid bilayer with properly folded and functional membrane proteins. Recently, styrene-maleic acid (StMA) copolymers have been shown to facilitate the formation of disc-like lipid bilayer mimetics that maintain the structural and dynamic integrity of membrane proteins. Here we report the controlled synthesis and characterization of StMA containing block copolymers. StMA polymers with different compositions and molecular weights were synthesized and characterized by size exclusion chromatography (SEC). These polymers act as macromolecular surfactants for 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol (POPG) lipids, forming disc like structures of the lipids with the polymer wrapping around the hydrophobic lipid edge. A combination of dynamic light scattering (DLS), solid-state nuclear magnetic resonance (SSNMR) spectroscopy, and transmission electron microscopy (TEM) was used to characterize the size of the nanoparticles created using these StMA polymers. At a weight ratio of 1.25:1 StMA to lipid, the nanoparticle size created is 28+1nm for a 2:1 ratio, 10+1nm for a 3:1 StMA ratio and 32+1nm for a 4:1 StMA ratio independent of the molecular weight of the polymer. Due to the polymer acting as a surfactant that forms disc like nanoparticles, we term these StMA based block copolymers "RAFT SMALPs". RAFT SMALPs show promise as a new membrane mimetic with different nanoscale sizes, which can be used for a wide variety of biophysical studies of membrane proteins.
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Craig
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Clark
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Indra D
authors.initials: ID
authors.lastname: Sahu
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Rongfu
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Nick D
authors.initials: ND
authors.lastname: Frantz
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: M Sameer
authors.initials: MS
authors.lastname: Al-Abdul-Wahid
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Carole
authors.initials: C
authors.lastname: Dabney-Smith
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States.
authors.forename: Dominik
authors.initials: D
authors.lastname: Konkolewicz
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, 651 E. High Street, Oxford, OH 45056, United States. Electronic address: gary.lorigan@miamioh.edu.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Lorigan
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008298:Maleates / Q000737:chemistry*; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry*; D058105:Polymerization; D011137:Polystyrenes / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D008298:Maleates; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011137:Polystyrenes; C024074:styrene-maleic acid polymer; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine
keywords: 2:1 StMA ratio; 3:1 StMA ratio; 4:1 StMA ratio; Dynamic light scattering; NOESY NMR; POPC/POPG vesicle; SSNMR spectroscopy; Styrene-maleic acid polymer