Morphology Transformation of Giant Vesicles by a Polyelectrolyte for an Artificial Model of a Membrane Protein for Endocytosis

Yoshida, Eri

doi:10.11648/j.css.20180301.12

Cited by 13 publications

(6 citation statements)

References 28 publications

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“…Unique models have been created employing the vesicles; for instance, the perforated vesicles for the nuclear envelope 25 , the villus-like structure for the villi 26 , the anastomosed tubular networks following a fenestrated sheet for the endoplasmic reticulum and Golgi apparatus 27 , the segment copolymers incorporated in the vesicle membrane for cholesterols embedded in the biomembrane 28 , and a polyelectrolyte that induces the budding separation for the membrane protein for endocytosis 29 . Recently, it has been found that the vesicles consisting of PMAA-b-P(BMA-r-MAA) undergo the erythrocyte-like transformation when heated in an aqueous methanol solution.…”

Section: Introductionmentioning

confidence: 99%

Human Erythrocyte-Like Transformation of Synthetic Polymer Vesicles

Yoshida

2021

Preprint

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This paper describes that synthetic polymer vesicles undergo a human erythrocyte-like transformation in response to temperature changes. The normally biconcave discoid erythrocytes, i.e., the discocytes, are transformed into various shapes by their environmental stresses. Field emission scanning electron microscopy (FE-SEM) demonstrates that the spherical vesicles consisting of poly(methacrylic acid)-block-poly(n-butyl methacrylate-random-methacrylic acid), PMAA-b-P(BMA-r-MAA), transform into echinocyte-like crenate vesicles due to expansion by the component copolymers in being freed from the vesicle surface when heated in an aqueous methanol solution. An increase in the vesicle concentration transforms the spherical vesicles into stomatocyte-like cup-shaped vesicles via the membrane perforation or double invaginations followed by membrane coupling and fusion. Light scattering studies reveal the reversibility and repeatability of the transformations. These findings indicate that the erythrocyte transformations are attributed to the inherent property of the bilayer membrane. The polymer vesicles are helpful for a better understanding of the biomembrane.

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Section: Introductionmentioning

confidence: 99%

Human Erythrocyte-Like Transformation of Synthetic Polymer Vesicles

Yoshida

2021

Preprint

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“…Giant vesicles in a micron size are significant as artificial biomembrane models for cells and organelles due to similarities in their size and structure [8,9] In particular, giant polymer vesicles consisting of a poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid) diblock copolymer, PMAA-b-P(MMA-r-MAA), have found many features in common with the biomembranes based on the morphologies [10], their transformation [11,12], stimuliresponsive behavior [13,14], and membrane permeability [15]. These similarities of the polymer vesicles to the biomembranes produced some unique models involved in the biomembranes; for instance, the villi structure using worm-like vesicles vertically aligned [16], the nuclear envelop morphology by perforated vesicles [17], the ion channel by incorporating ionic compounds into the hydrophobic vesicle core [15], the budding separation of the vesicle membrane using a polyelectrolyte inductor for cytosis [18], and the artificial sterol using the P(MMA-r-MAA) segment copolymer [19]. It was found that the polymer vesicles extended tubules from their surface as the neurons extended their neurites.…”

Section: Introductionmentioning

confidence: 99%

Neuron-like tubule extension of giant polymer vesicles

Yoshida

2021

Chem Rep

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Giant polymer vesicles consisting of amphiphilic diblock copolymers are helpful as artificial biomembrane models based on many similarities in their size, structure, morphological transformation, membrane permeability, etc. This paper describes the creation of neuron-like tubule extension employing the polymer vesicles. The polymerization-induced self-assembly was performed in the presence of micron-sized spherical vesicles consisting of poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid), PMAA-b-P(MMA-r-MAA), through the photo nitroxide-mediated controlled/living radical polymerization (photo-NMP) using 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO) as the mediator. The photo-NMP of methyl methacrylate (MMA) and methacrylic acid (MAA) was carried out in an aqueous methanol solution (CH3OH/H2O = 3/1 v/v) using poly(methacrylic acid) (PMAA) end-capped with MTEMPO and the spherical vesicles of PMAA141-b-P(MMA0.831-r-MAA0.169)368 with an 11.7-mm diameter. The vesicles projected many processes on their surface during the early stage of the polymerization. As the polymerization progressed, only one or two of the processes extended to thick tubules, accompanied by the slow growth of thin tubules. Further progress of the polymerization elongated the thick tubules and caused branching of the tubules. The tubules had a vesicular structure because cup-like vesicles joined in line were formed during the initial stage of the extension. The polymerization livingness supported the tubule extension based on a linear increase in the molecular weight of the component copolymer and a negligible change in the molecular weight distribution versus the monomer conversion. The spherical vesicles were similar to the neurons in the tubule extension for the initial projection, followed by the elongation and branching. This similarity implies that the neurite extension in the neurons is related to the inherent property of the bilayer membrane.

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“…Giant vesicles in a micron size are artificial models of biomembrane for cells and organelles due to their similarities in size and structure [8]. The giant polymer vesicles consisting of poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid), PMAA-b-P(MMAr-MAA), have produced some significant models; for instance, the villi model with vertically aligned worm-like vesicles [9], the nuclear envelop model using perforated vesicles [10], the membrane protein model for endocytosis employing a polyelectrolyte [11], and the sterol model including the P(MMA-r-MAA) segment copolymer [12]. These models are based on similarities to the biomembranes in morphology [13,14], stimuli-responsive behavior [15], and membrane impermeability [16].…”

Section: Introductionmentioning

confidence: 99%

Giant Vesicles of Amphiphilic Diblock Copolymer with Branched Side Chains

Yoshida¹

2021

CSS

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Biomolecules of lipids and proteins optimize the hydrophobicity to precisely form their three-dimensional structures. The branching of hydrocarbon chains is appropriate for fine-tuning the hydrophobicity of the molecules because it provides a slight reduction in hydrophobicity. This paper describes the morphological changes of vesicles formed by an amphiphilic diblock copolymer supporting branched side chains in the hydrophobic block to elucidate the steric effect of the side chains on the morphology. The vesicles consisting of poly(methacrylic acid)-block-poly(isopropyl methacrylate-randommethacrylic acid), PMAA-b-P(iPMA-r-MAA), were obtained by the polymerization-induced self-assembly using the photonitroxide mediated controlled/living radical polymerization (photo-NMP) in an aqueous methanol solution (methanol/water=3/1 v/v). PMAA-b-P(iPMA-r-MAA) with a very high ratio of the iPMA units produced spherical vesicles. As the iPMA ratio decreased, the vesicles shrank, expanded again, and changed into sheets. The chain length of the hydrophobic block also dominated the morphology. For the high iPMA ratio constant, the copolymers with a short block produced two domains of micron-sized spherical vesicles and unspecific nano-sized particles fused. An increase in the block length changed the nanoparticles into nanospheres, accompanied by an increase in the number of micron-sized spherical vesicles. By further extending the block length, most of the nanospheres grew into micron-sized spherical vesicles. On the other hand, for the low iPMA ratio constant, an increase in the length of the hydrophobic chain changed the unspecific nanoparticles sheets into aggregates with an inverted hexagonal phase reticularly perforated. The PMAA-b-P(n-propyl methacrylate-r-MAA) copolymer produced flexible sheets with a smooth surface without any pores, while PMAA-b-P(methyl methacrylate-r-MAA) provided rods of laminated sheets. It was found that the formation of the inverted hexagonal phase was due to the steric repulsion of the bulky isopropyl groups in the hydrophobic blocks. These findings indicate that the morphology of the vesicles is manipulated not only by the hydrophobicity of the copolymer, but also by the bulkiness of the branched side chain in the hydrophobic block.

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Morphology Transformation of Giant Vesicles by a Polyelectrolyte for an Artificial Model of a Membrane Protein for Endocytosis

Cited by 13 publications

References 28 publications

Human Erythrocyte-Like Transformation of Synthetic Polymer Vesicles

Human Erythrocyte-Like Transformation of Synthetic Polymer Vesicles

Neuron-like tubule extension of giant polymer vesicles

Giant Vesicles of Amphiphilic Diblock Copolymer with Branched Side Chains

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