Hybrid membranes of lipids and diblock copolymers: From homogeneity to rafts to phase separation

Hu, Ssu Wei; Huang, Chun Yen; Tsao, Heng Kwong; Sheng, Yu Jane

doi:10.1103/physreve.99.012403

Cited by 19 publications

(23 citation statements)

References 41 publications

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“…Also, from a thermodynamic aspect, at low lipid mol% entropy tends to dominate leading to a uniform distribution of the lipid within the membrane. 115 Increasing the mol% of incorporated lipids resulted in a growth of the domains followed by complete phase separation at 50% molar lipid compositions, budding and fission. 113,114 At higher lipid fractions, enthalpy dominates due to the hydrophobic mismatch between the polymer and lipid, thus leading to phase separation and domain formation.…”

Section: Biohybrid Guvs: Membrane Properties Composition and Functiomentioning

confidence: 99%

“…113,114 At higher lipid fractions, enthalpy dominates due to the hydrophobic mismatch between the polymer and lipid, thus leading to phase separation and domain formation. 115 The membrane properties are also governed by the molar composition and is more fluid-like at high polymer concentrations or more elastic-like at high lipid composition. 116 However, it is important to note that formation of domains can lead to membranes with decreased toughness with destabilization occurring at the lipid/polymer boundaries.…”

Section: Biohybrid Guvs: Membrane Properties Composition and Functiomentioning

confidence: 99%

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Biomolecule–polymer hybrid compartments: combining the best of both worlds

Meyer

Abram

Craciun

et al. 2020

Phys. Chem. Chem. Phys.

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Section: Biohybrid Guvs: Membrane Properties Composition and Functiomentioning

confidence: 99%

Section: Biohybrid Guvs: Membrane Properties Composition and Functiomentioning

confidence: 99%

Biomolecule–polymer hybrid compartments: combining the best of both worlds

Meyer

Abram

Craciun

et al. 2020

Phys. Chem. Chem. Phys.

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“…Membranes formed by pure diblock copolymers are bilayered [29] while monolayered, bilayered, or mixed membranes can be developed by triblock copolymers [30,31]. It is known that A x B y A x triblock copolymers can exhibit two possible conformations, U-(loop) or I-(bridge) shape, in the polymer membrane [32][33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

“…Since the A x B y A x triblock copolymers can exhibit two possible conformations, loop or bridge, the formations of asymmetric lipid/triblock hybrid membranes are inherently more complicated than their lipid/diblock counterparts [29][30][31]. The lipid/triblock hybrid membrane is called symmetric as the fractions of the loop-shape copolymers in the upper and lower leaflets are the same, and is designated asymmetric otherwise.…”

Section: Introductionmentioning

confidence: 99%

Formation of Asymmetric and Symmetric Hybrid Membranes of Lipids and Triblock Copolymers

et al. 2020

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Hybrid membranes formed by co-assembly of AxByAx (hydrophilic-hydrophobic-hydrophilic) triblock copolymers into lipid bilayers are investigated by dissipative particle dynamics. Homogeneous hybrid membranes are developed as lipids and polymers are fully compatible. The polymer conformations can be simply classified into bridge- and loop-structures in the membranes. It is interesting to find that the long-time fraction of loop-conformation ( f L ) of copolymers in the membrane depends significantly on the hydrophilic block length (x). As x is small, an equilibrium f L * always results irrespective of the initial conformation distribution and its value depends on the hydrophobic block length (y). For large x, f L tends to be time-invariant because polymers are kinetically trapped in their initial structures. Our findings reveal that only symmetric hybrid membranes are formed for small x, while membranes with stable asymmetric leaflets can be constructed with large x. The effects of block lengths on the polymer conformations, such as transverse and lateral spans ( d ⊥ and d ‖ ) of bridge- and loop-conformations, are discussed as well.

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“…Hybrid vesicles aim to combine the properties of biomimetic liposomes and synthetic polymersomes into composite membrane-bound capsules with broader tuneability of material properties [1][2][3][4][5][6][7][8][9][10]. This expanded material parameter space is anticipated to be beneficial in the development of hollow vesicle structures for technological applications such as sensors, biotechnology, nanoreactors, synthetic biology and formulated products, including those intended for medicinal purposes [11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Vesicle Stability under Sterilisation and Preservation Processes Used in the Manufacture of Medicinal Formulations

et al. 2020

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Sterilisation and preservation of vesicle formulations are important considerations for their viable manufacture for industry applications, particular those intended for medicinal use. Here, we undertake an initial investigation of the stability of hybrid lipid-block copolymer vesicles to common sterilisation and preservation processes, with particular interest in how the block copolymer component might tune vesicle stability.We investigate two sizes of polybutadiene-block-poly(ethylene oxide) polymers (PBd 12 -PEO 11 and PBd 22 -PEO 14 ) mixed with the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) considering the encapsulation stability of a fluorescent cargo and the colloidal stability of vesicle size distributions. We find that autoclaving and lyophilisation cause complete loss of encapsulation stability under the conditions studied here. Filtering through 200 nm pores appears to be viable for sterilisation for all vesicle compositions with comparatively low release of encapsulated cargo, even for vesicle size distributions which extend beyond the 200 nm filter pore size. Freeze-thaw of vesicles also shows promise for the preservation of hybrid vesicles with high block copolymer content. We discuss the process stability of hybrid vesicles in terms of the complex mechanical interplay between bending resistance, stretching elasticity and lysis strain of these membranes and propose strategies for future work to further enhance the process stability of these vesicle formulations.Polymers 2020, 12, 914 2 of 17 liposomes can have inherent instabilities. Their membranes are highly flexible under bending deformations, but weak under stretching deformations, with a lysis strain of less than 5% [28,29]. The labile fluidity of the membrane can lead to transient membrane defects that frustrates long term encapsulation stability and lipid peroxidation can cause chemical instabilities in these structures.Polymersomes, due to their synthetic nature, are often less biocompatible than their lipid counterparts but offer greater mechanical stability and a broader chemical parameter space [30]. Amphiphilic copolymers that form vesicles can have several different architectures, the most common being AB diblock (A = hydrophilic, B = hydrophobic) [6], ABA [31] and ABC tri-block polymers [32] where A and C are chemically different hydrophilic blocks and finally graft copolymers [33]. Formation of polymersomes depends on the amphiphilic co-polymers molecular weight, polydispersity and hydrophilic/hydrophobic block lengths ratio, which is ideally less than 1:3 to form vesicular structures [34]. Their membranes are often thicker than liposome membranes, which provides greater bending resistance and their enhanced elasticity under stretching makes them tough and durable [22]. The polymer chemistry can be designed to minimise chemical instability but also to incorporate novel functionality. In blending liposomes and polymersomes to create hybrid vesicles, the ambition is to combine advantageous properties of these m...

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Hybrid membranes of lipids and diblock copolymers: From homogeneity to rafts to phase separation

Cited by 19 publications

References 41 publications

Biomolecule–polymer hybrid compartments: combining the best of both worlds

Biomolecule–polymer hybrid compartments: combining the best of both worlds

Formation of Asymmetric and Symmetric Hybrid Membranes of Lipids and Triblock Copolymers

Hybrid Vesicle Stability under Sterilisation and Preservation Processes Used in the Manufacture of Medicinal Formulations

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