Polymer Vesicles

Förster, Stephan; Borchert, Kwe

doi:10.1002/0471440264.pst517

Cited by 14 publications

(20 citation statements)

References 212 publications

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“…The average radius in the image is 75 ± 16 nm, which is close to that of SO(14–2.5)-60. It is known that the chain exchange rate ( k (s –1 )) of amphiphilic chains in a suspension is proportional to exp(−γ), where γ is interfacial tension between hydrophobic part and a solvent . Therefore, the size irreversibility of PS–PEO polymersomes is due to a kinetically locked-in structure when the IL content is dominant.…”

Section: Resultsmentioning

confidence: 99%

Size Control and Fractionation of Ionic Liquid Filled Polymersomes with Glassy and Rubbery Bilayer Membranes

Lodge

2016

Langmuir

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We demonstrate control over the size of ionic liquid (IL) filled polymeric vesicles (polymersomes) by three distinct methods: mechanical extrusion, cosolvent-based processing in an IL, and fractionation of polymersomes in a biphasic system of IL and water. For the representative ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI])), the size and dispersity of polymersomes formed from 1,2-polybutadiene-b-poly(ethylene oxide) (PB-PEO) and polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock copolymers were shown to be sensitive to assembly conditions. During mechanical extrusion through a polycarbonate membrane, the relatively larger polymersomes were broken up and reorganized into vesicles with mean size comparable to the membrane pore (100 nm radius); the distribution width also decreased significantly after only a few passes. Other routes were studied using the solvent-switch or cosolvent (CS) method, whereby the initial content of the cosolvent and the PEO block length of PS-PEO were systemically changed. The nonvolatility of the ionic liquid directly led to the desired concentration of polymersomes in the ionic liquid using a single step, without the dialysis conventionally used in aqueous systems, and the mean vesicle size depended on the amount of cosolvent employed. Finally, selective phase transfer of PS-PEO polymersomes based on size was used to extract larger polymersomes from the IL to the aqueous phase via interfacial tension controlled phase transfer. The interfacial tension between the PS membrane and the aqueous phase was varied with the concentration of sodium chloride (NaCl) in the aqueous phase; then the larger polymersomes were selectively separated to the aqueous phase due to differences in shielding of the hydrophobic core (PS) coverage by the hydrophilic corona brush (PEO). This novel fractionation is a simple separation process without any special apparatus and can help to prepare monodisperse polymersomes and also separate unwanted morphologies (in this case, worm-like micelles).

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Section: Resultsmentioning

confidence: 99%

Size Control and Fractionation of Ionic Liquid Filled Polymersomes with Glassy and Rubbery Bilayer Membranes

Lodge

2016

Langmuir

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“…In fact, there are relatively more reports on the observations of CAC-polymersomes than CRC-polymersomes. 20,21 Fig. 3(c) also shows the comparison of the thickness of the rod domain between perfect alignment (h * r ¼ 0.7x) and that of the realistic one (h r ).…”

Section: Resultsmentioning

confidence: 99%

“…For example, they can function as drug carriers, [9][10][11][12][13][14] chemical vehicles 15,16 or cell imitators. [17][18][19] There are numerous different types of block copolymers such as diblock, triblock, star, or gra copolymers 20,21 that can be used to form polymersomes. One special type of amphiphilic copolymer is the copolymer containing a rigid rod-like block.…”

Section: Introductionmentioning

confidence: 99%

Self-assembled polymersomes formed by symmetric, asymmetric and side-chain-tethered coil–rod–coil triblock copolymers

et al. 2014

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Self-assembly behaviors of coil-rod-coil copolymers in selective solvents are explored by dissipative particle dynamics. The morphological phase diagram as a function of rod length and coil length shows five distinct types of aggregates, including spherical micelles, worm-like micelles, disk-like aggregates, honeycomb structures, and polymersomes. Small polymersomes are formed at rather poor alignment associated with monolayered rod domains. Some of the rods are even lying perpendicular to the radial direction. For symmetric copolymers (CmRxCm), the condition of vesicle formation is restricted to short coil and rod lengths. To favor the formation of CRC-polymersomes, two architecture modifications are adopted. One is to increase the coil length asymmetrically to be CmRxCn, where n > m. The other one is to tether a T-block onto the middle of the rod-block as Cm(RxTy)Cm copolymers. For those CRC-polymersomes, structural, transport, and mechanical properties of the vesicular membrane are determined, including membrane thickness, area density of coil blocks, order parameter, solvent permeability, frequency of flip-flop, membrane tension, and stretching and bending moduli. The influences of the coil length (n) and tethered block length (y) on membrane properties are examined. Finally, the mechanism of membrane fusion between CRC-polymersomes is investigated. The fusion process involves four stages and in the contact region the rods lying perpendicular to the radial direction of the polymersome play the key role. The encounter of two vesicles may result in a fused, hemifused, or non-fused polymersome. The final fate is determined by the competition between membrane tension and the steric barrier of the coil corona. The fusion outcome may change if the tension is altered by manipulating the lumen pressure.

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“…Invaginated vescicle shapes occur for vesicles with large bilayer asymmetry and very small interior volume/surface ratios. 1 Surprisingly, a covalent attachment of aldehyde-functionalized vesicles is also possible for unfunctionalized glass surfaces, most likely via stable acetal formation with the Si-OH groups. We suppose that the locally high concentration of aldehyde end groups close to the glass surface with its high local concentration of OH groups drives the reaction toward acetal formation.…”

Section: Resultsmentioning

confidence: 99%

Covalent Attachment of Polymersomes to Surfaces

et al. 2010

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We show that vesicles made of block copolymers with aldehyde end groups can be covalently attached to aminated and non-aminated, untreated glass surfaces. The attached vesicles were sufficiently stable to allow a detailed investigation of vesicle shapes by confocal laser scanning microscopy (CLSM) and AFM in aqueous solutions allowing reconstruction of 3D images of the vesicle structure. Covalently attached PCL-PEO, PLA-PEO, and PI-PEO block copolymer vesicles have different footprint areas and different shapes due to their differences in bilayer stiffness.

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Polymer Vesicles

Cited by 14 publications

References 212 publications

Size Control and Fractionation of Ionic Liquid Filled Polymersomes with Glassy and Rubbery Bilayer Membranes

Size Control and Fractionation of Ionic Liquid Filled Polymersomes with Glassy and Rubbery Bilayer Membranes

Self-assembled polymersomes formed by symmetric, asymmetric and side-chain-tethered coil–rod–coil triblock copolymers

Covalent Attachment of Polymersomes to Surfaces

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