The Experts below are selected from a list of 63579 Experts worldwide ranked by ideXlab platform
Sukkyun Ahn - One of the best experts on this subject based on the ideXlab platform.
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surface aligned main chain liquid crystalline elastomers tailored properties by the choice of amine chain extenders
Macromolecules, 2018Co-Authors: Hyeongho Yoon, Daeyoon Kim, Kwangun Jeong, Sukkyun AhnAbstract:A promising way to induce Shape Transformation in soft materials is via spatial variation in the orientation of the alignment of liquid crystalline elastomers (LCEs). Here, we improve the nascent thermomechanial Shape Transformation in main-chain LCEs prepared via aza-Michael addition reactions. Specifically, increasing the alkyl length in the n-alkylamine chain extender effectively reduces the actuation temperature by destabilizing the nematic phase as well as reduces the glass transition temperature (Tg) by increasing the free volume. In addition, incorporating a hydroxyl end-group in the amine chain extender (i.e., n-alkanolamine) increases the actuation strain and improves the film quality by preventing side-chain aggregates of n-alkylamine-functionalized LCEs. Interestingly, uniaxially aligned n-alkanolamine-functionalized LCEs exhibit an unprecedentedly large elongation and an enhanced toughness even along the loading direction likely due to hydrogen bonding between chains. Thus, our study highlight...
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Surface Aligned Main-Chain Liquid Crystalline Elastomers: Tailored Properties by the Choice of Amine Chain Extenders
2018Co-Authors: Hyeongho Yoon, Daeyoon Kim, Kwangun Jeong, Sukkyun AhnAbstract:A promising way to induce Shape Transformation in soft materials is via spatial variation in the orientation of the alignment of liquid crystalline elastomers (LCEs). Here, we improve the nascent thermomechanial Shape Transformation in main-chain LCEs prepared via aza-Michael addition reactions. Specifically, increasing the alkyl length in the n-alkylamine chain extender effectively reduces the actuation temperature by destabilizing the nematic phase as well as reduces the glass transition temperature (Tg) by increasing the free volume. In addition, incorporating a hydroxyl end-group in the amine chain extender (i.e., n-alkanolamine) increases the actuation strain and improves the film quality by preventing side-chain aggregates of n-alkylamine-functionalized LCEs. Interestingly, uniaxially aligned n-alkanolamine-functionalized LCEs exhibit an unprecedentedly large elongation and an enhanced toughness even along the loading direction likely due to hydrogen bonding between chains. Thus, our study highlights that the choice of amine chain extender during LCEs synthesis can be an efficient strategy to tailor the properties as well as to provide a new functionality in the LCEs which may expand their range of applications in Shape morphing devices, smart coatings, and dynamic substrates
Daniela A Wilson - One of the best experts on this subject based on the ideXlab platform.
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Stomatocyte in Stomatocyte: A New Shape of Polymersome Induced via Chemical-Addition Methodology.
Nano Letters, 2018Co-Authors: Yongjun Men, Geertjan A Janssen, Roger S. M. Rikken, Daniela A WilsonAbstract:Accurate control of the Shape Transformation of polymersome is an important and interesting challenge that spans across disciplines such as nanomedicine and nanomachine. Here, we report a fast and facile methodology of Shape manipulation of polymersome via out-of-equilibrium polymer self-assembly and Shape change by chemical addition of additives. Due to its increased permeability, hydrophilicity, and fusogenic properties, poly(ethylene oxide) was selected as the additive for bringing the system out of equilibrium via fast addition into the polymersome organic solution. A new Shape, stomatocyte-in-stomatocyte (sto-in-sto), is obtained for the first time. Moreover, fast Shape Transformation within less than 1 min to other relevant Shapes such as stomatocyte and large compound vesicles was also obtained and accurately controlled in a uniform dispersion. This methodology is demonstrated as a general strategy with which to push the assembly further out of equilibrium to generate unusual nanostructures in a co...
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Stomatocyte in Stomatocyte: A New Shape of Polymersome Induced via Chemical-Addition Methodology
2018Co-Authors: Yongjun Men, Geert-jan Janssen, Roger S. M. Rikken, Daniela A WilsonAbstract:Accurate control of the Shape Transformation of polymersome is an important and interesting challenge that spans across disciplines such as nanomedicine and nanomachine. Here, we report a fast and facile methodology of Shape manipulation of polymersome via out-of-equilibrium polymer self-assembly and Shape change by chemical addition of additives. Due to its increased permeability, hydrophilicity, and fusogenic properties, poly(ethylene oxide) was selected as the additive for bringing the system out of equilibrium via fast addition into the polymersome organic solution. A new Shape, stomatocyte-in-stomatocyte (sto-in-sto), is obtained for the first time. Moreover, fast Shape Transformation within less than 1 min to other relevant Shapes such as stomatocyte and large compound vesicles was also obtained and accurately controlled in a uniform dispersion. This methodology is demonstrated as a general strategy with which to push the assembly further out of equilibrium to generate unusual nanostructures in a controllable and fast manner
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dynamic loading and unloading of proteins in polymeric stomatocytes formation of an enzyme loaded supramolecular nanomotor
ACS Nano, 2016Co-Authors: Loai K. E. A. Abdelmohsen, Gajanan M Pawar, Geertjan A Janssen, Marlies Nijemeisland, Roeland J. M. Nolte, Daniela A WilsonAbstract:Self-powered artificial nanomotors are currently attracting increased interest as mimics of biological motors but also as potential components of nanomachinery, robotics, and sensing devices. We have recently described the controlled Shape Transformation of polymersomes into bowl-Shaped stomatocytes and the assembly of platinum-driven nanomotors. However, the platinum encapsulation inside the structures was low; only 50% of the structures contained the catalyst and required both high fuel concentrations for the propelling of the nanomotors and harsh conditions for the Shape Transformation. Application of the nanomotors in a biological setting requires the nanomotors to be efficiently propelled by a naturally available energy source and at biological relevant concentrations. Here we report a strategy for enzyme entrapment and nanomotor assembly via controlled and reversible folding of polymersomes into stomatocytes under mild conditions, allowing the encapsulation of the proteins inside the stomach with al...
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Dynamic Loading and Unloading of Proteins in Polymeric Stomatocytes: Formation of an Enzyme-Loaded Supramolecular Nanomotor.
ACS Nano, 2016Co-Authors: Loai K. E. A. Abdelmohsen, Gajanan M Pawar, Geertjan A Janssen, Marlies Nijemeisland, Roeland J. M. Nolte, Jan C. M. Van Hest, Daniela A WilsonAbstract:Self-powered artificial nanomotors are currently attracting increased interest as mimics of biological motors but also as potential components of nanomachinery, robotics, and sensing devices. We have recently described the controlled Shape Transformation of polymersomes into bowl-Shaped stomatocytes and the assembly of platinum-driven nanomotors. However, the platinum encapsulation inside the structures was low; only 50% of the structures contained the catalyst and required both high fuel concentrations for the propelling of the nanomotors and harsh conditions for the Shape Transformation. Application of the nanomotors in a biological setting requires the nanomotors to be efficiently propelled by a naturally available energy source and at biological relevant concentrations. Here we report a strategy for enzyme entrapment and nanomotor assembly via controlled and reversible folding of polymersomes into stomatocytes under mild conditions, allowing the encapsulation of the proteins inside the stomach with almost 100% efficiency and retention of activity. The resulting enzyme-driven nanomotors are capable of propelling these structures at low fuel concentrations (hydrogen peroxide or glucose) via a one-enzyme or two-enzyme system. The confinement of the enzymes inside the stomach does not hinder their activity and in fact facilitates the transfer of the substrates, while protecting them from the deactivating influences of the media. This is particularly important for future applications of nanomotors in biological settings especially for systems where fast autonomous movement occurs at physiological concentrations of fuel.
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Dynamic Loading and Unloading of Proteins in Polymeric Stomatocytes: Formation of an Enzyme-Loaded Supramolecular Nanomotor
2016Co-Authors: Loai K. E. A. Abdelmohsen, Geertjan A Janssen, Marlies Nijemeisland, Roeland J. M. Nolte, Jan C. M. Van Hest, Gajanan M. Pawar, Daniela A WilsonAbstract:Self-powered artificial nanomotors are currently attracting increased interest as mimics of biological motors but also as potential components of nanomachinery, robotics, and sensing devices. We have recently described the controlled Shape Transformation of polymersomes into bowl-Shaped stomatocytes and the assembly of platinum-driven nanomotors. However, the platinum encapsulation inside the structures was low; only 50% of the structures contained the catalyst and required both high fuel concentrations for the propelling of the nanomotors and harsh conditions for the Shape Transformation. Application of the nanomotors in a biological setting requires the nanomotors to be efficiently propelled by a naturally available energy source and at biological relevant concentrations. Here we report a strategy for enzyme entrapment and nanomotor assembly via controlled and reversible folding of polymersomes into stomatocytes under mild conditions, allowing the encapsulation of the proteins inside the stomach with almost 100% efficiency and retention of activity. The resulting enzyme-driven nanomotors are capable of propelling these structures at low fuel concentrations (hydrogen peroxide or glucose) via a one-enzyme or two-enzyme system. The confinement of the enzymes inside the stomach does not hinder their activity and in fact facilitates the transfer of the substrates, while protecting them from the deactivating influences of the media. This is particularly important for future applications of nanomotors in biological settings especially for systems where fast autonomous movement occurs at physiological concentrations of fuel
Hyeongho Yoon - One of the best experts on this subject based on the ideXlab platform.
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surface aligned main chain liquid crystalline elastomers tailored properties by the choice of amine chain extenders
Macromolecules, 2018Co-Authors: Hyeongho Yoon, Daeyoon Kim, Kwangun Jeong, Sukkyun AhnAbstract:A promising way to induce Shape Transformation in soft materials is via spatial variation in the orientation of the alignment of liquid crystalline elastomers (LCEs). Here, we improve the nascent thermomechanial Shape Transformation in main-chain LCEs prepared via aza-Michael addition reactions. Specifically, increasing the alkyl length in the n-alkylamine chain extender effectively reduces the actuation temperature by destabilizing the nematic phase as well as reduces the glass transition temperature (Tg) by increasing the free volume. In addition, incorporating a hydroxyl end-group in the amine chain extender (i.e., n-alkanolamine) increases the actuation strain and improves the film quality by preventing side-chain aggregates of n-alkylamine-functionalized LCEs. Interestingly, uniaxially aligned n-alkanolamine-functionalized LCEs exhibit an unprecedentedly large elongation and an enhanced toughness even along the loading direction likely due to hydrogen bonding between chains. Thus, our study highlight...
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Surface Aligned Main-Chain Liquid Crystalline Elastomers: Tailored Properties by the Choice of Amine Chain Extenders
2018Co-Authors: Hyeongho Yoon, Daeyoon Kim, Kwangun Jeong, Sukkyun AhnAbstract:A promising way to induce Shape Transformation in soft materials is via spatial variation in the orientation of the alignment of liquid crystalline elastomers (LCEs). Here, we improve the nascent thermomechanial Shape Transformation in main-chain LCEs prepared via aza-Michael addition reactions. Specifically, increasing the alkyl length in the n-alkylamine chain extender effectively reduces the actuation temperature by destabilizing the nematic phase as well as reduces the glass transition temperature (Tg) by increasing the free volume. In addition, incorporating a hydroxyl end-group in the amine chain extender (i.e., n-alkanolamine) increases the actuation strain and improves the film quality by preventing side-chain aggregates of n-alkylamine-functionalized LCEs. Interestingly, uniaxially aligned n-alkanolamine-functionalized LCEs exhibit an unprecedentedly large elongation and an enhanced toughness even along the loading direction likely due to hydrogen bonding between chains. Thus, our study highlights that the choice of amine chain extender during LCEs synthesis can be an efficient strategy to tailor the properties as well as to provide a new functionality in the LCEs which may expand their range of applications in Shape morphing devices, smart coatings, and dynamic substrates
Jan C. M. Van Hest - One of the best experts on this subject based on the ideXlab platform.
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Morphology Under Control: Engineering Biodegradable Stomatocytes
2017Co-Authors: Imke A. B. Pijpers, Loai K. E. A. Abdelmohsen, David S. Williams, Jan C. M. Van HestAbstract:Biodegradable nanoarchitectures, with well-defined morphological features, are of great importance for nanomedical research; however, understanding (and thereby engineering) their formation is a substantial challenge. Herein, we uncover the supramolecular potential of PEG–PDLLA copolymers by exploring the physicochemical determinants that result in the Transformation of spherical polymersomes into stomatocytes. To this end, we have engineered blended polymersomes (comprising copolymers with varying lengths of PEG), which undergo solvent-dependent reorganization inducing negative spontaneous membrane curvature. Under conditions of anisotropic solvent composition across the PDLLA membrane, facilitated by the dialysis methodology, we demonstrate osmotically induced stomatocyte formation as a consequence of changes in PEG solvation, inducing negative spontaneous membrane curvature. Controlled formation of unprecedented, biodegradable stomatocytes represents the unification of supramolecular engineering with the theoretical understanding of Shape Transformation phenomena
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Dynamic Loading and Unloading of Proteins in Polymeric Stomatocytes: Formation of an Enzyme-Loaded Supramolecular Nanomotor.
ACS Nano, 2016Co-Authors: Loai K. E. A. Abdelmohsen, Gajanan M Pawar, Geertjan A Janssen, Marlies Nijemeisland, Roeland J. M. Nolte, Jan C. M. Van Hest, Daniela A WilsonAbstract:Self-powered artificial nanomotors are currently attracting increased interest as mimics of biological motors but also as potential components of nanomachinery, robotics, and sensing devices. We have recently described the controlled Shape Transformation of polymersomes into bowl-Shaped stomatocytes and the assembly of platinum-driven nanomotors. However, the platinum encapsulation inside the structures was low; only 50% of the structures contained the catalyst and required both high fuel concentrations for the propelling of the nanomotors and harsh conditions for the Shape Transformation. Application of the nanomotors in a biological setting requires the nanomotors to be efficiently propelled by a naturally available energy source and at biological relevant concentrations. Here we report a strategy for enzyme entrapment and nanomotor assembly via controlled and reversible folding of polymersomes into stomatocytes under mild conditions, allowing the encapsulation of the proteins inside the stomach with almost 100% efficiency and retention of activity. The resulting enzyme-driven nanomotors are capable of propelling these structures at low fuel concentrations (hydrogen peroxide or glucose) via a one-enzyme or two-enzyme system. The confinement of the enzymes inside the stomach does not hinder their activity and in fact facilitates the transfer of the substrates, while protecting them from the deactivating influences of the media. This is particularly important for future applications of nanomotors in biological settings especially for systems where fast autonomous movement occurs at physiological concentrations of fuel.
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Dynamic Loading and Unloading of Proteins in Polymeric Stomatocytes: Formation of an Enzyme-Loaded Supramolecular Nanomotor
2016Co-Authors: Loai K. E. A. Abdelmohsen, Geertjan A Janssen, Marlies Nijemeisland, Roeland J. M. Nolte, Jan C. M. Van Hest, Gajanan M. Pawar, Daniela A WilsonAbstract:Self-powered artificial nanomotors are currently attracting increased interest as mimics of biological motors but also as potential components of nanomachinery, robotics, and sensing devices. We have recently described the controlled Shape Transformation of polymersomes into bowl-Shaped stomatocytes and the assembly of platinum-driven nanomotors. However, the platinum encapsulation inside the structures was low; only 50% of the structures contained the catalyst and required both high fuel concentrations for the propelling of the nanomotors and harsh conditions for the Shape Transformation. Application of the nanomotors in a biological setting requires the nanomotors to be efficiently propelled by a naturally available energy source and at biological relevant concentrations. Here we report a strategy for enzyme entrapment and nanomotor assembly via controlled and reversible folding of polymersomes into stomatocytes under mild conditions, allowing the encapsulation of the proteins inside the stomach with almost 100% efficiency and retention of activity. The resulting enzyme-driven nanomotors are capable of propelling these structures at low fuel concentrations (hydrogen peroxide or glucose) via a one-enzyme or two-enzyme system. The confinement of the enzymes inside the stomach does not hinder their activity and in fact facilitates the transfer of the substrates, while protecting them from the deactivating influences of the media. This is particularly important for future applications of nanomotors in biological settings especially for systems where fast autonomous movement occurs at physiological concentrations of fuel
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Probing morphological changes in polymersomes with magnetic birefringence
Chemical Communications, 2013Co-Authors: Roger S. M. Rikken, Roeland J. M. Nolte, Jan C. M. Van Hest, Peter C. M. Christianen, Jan C. Maan, Harmen H. M. Kerkenaar, Daniela A WilsonAbstract:Magnetic birefringence was used for in situ monitoring of the morphological changes in diamagnetic polymersomes during Shape-Transformation by dialysis. The birefringence was found to be very sensitive to the polymersome morphology, as determined by electron microscopy. The deflation of polymersomes into disks was observed, followed by a bending and partial inflation into stomatocytes.
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Entrapment of Metal Nanoparticles in Polymer Stomatocytes
2012Co-Authors: Daniela A Wilson, Roeland J. M. Nolte, Jan C. M. Van HestAbstract:Polymersomes assembled from amphiphilic block copolymers containing a glassy hydrophobic segment can be further re-engineered to perform a controlled Shape Transformation from a thermodynamically stable spherical morphology to a kinetically trapped stomatocyte structure. The stable bowl-Shape stomatocyte morphology is ideal for the specific physical entrapment of nanoparticles for potential use in heterogeneous catalysis and drug delivery. Herein we report two approaches to obtain a selective and controlled entrapment of platinum nanoparticles (PtNP) of different sizes and Shapes inside the stomatocyte structure. In the first approach, the stomach of the stomatocytes is used to template the growth of the PtNP by controlling and confining the nucleation points inside the cavity. In the second method, preformed nanoparticles are engulfed during the stomatocyte formation process. Synergistically, the reverse effect is observed, that is, differently Shaped nanoparticles were shown to exhibit a templating effect on the stomach formation of the stomatocytes
Piotr Zielenkiewicz - One of the best experts on this subject based on the ideXlab platform.
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theoretical model of thalassemic erythrocyte Shape Transformation
Journal of Theoretical Biology, 2008Co-Authors: P Pawlowski, Beata Burzynska, Piotr ZielenkiewiczAbstract:Abstract Our earlier model of reticulocyte Shape Transformation [Pawlowski, P.H., Burzynska, B., Zielenkiewicz, P., 2006. Theoretical model of reticulocyte to erythrocyte Shape Transformation. J. Theor. Biol. 243, 24–38] was applied to explain the morphological properties of thalassemic erythrocytes. Modification of the standard set of parameters of the model, describing minimal cell volume, membrane bending rigidity, and membrane tension, allowed for simulation of development of α - and β -thalassemic cells from splenectomized and nonsplenectomized individuals. This resulted in observation of thin rim discocytes, tailed erythrocytes and oval forms, as well as in differentiation of time of the cell Shape metamorphosis. A comparative analysis of the susceptibility of thalassemic and normal erythrocytes to undergo deformation as well of their stability was performed.
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theoretical model of reticulocyte to erythrocyte Shape Transformation
Journal of Theoretical Biology, 2006Co-Authors: P Pawlowski, Beata Burzynska, Piotr ZielenkiewiczAbstract:Abstract A theoretical model describing the kinetics of reticulocyte Shape Transformation was developed. The model considers the evolution of a simple cellular Shape under transmembrane pressure difference, and proposes a four-parameter axisymmetric approximation of the cell surface. The mathematical analysis considers plasma membrane tension in the plane of bilayer leaflets, membrane spontaneous curvature and transmembrane transport of water. Cytoskeleton dilatational and shear rigidity, and the energetic barrier preventing the decrease of cell volume below a certain minimum are also incorporated. The set of adequate physical assumptions allowed for formulation of the equation for free energy of the investigated system. Computer simulations of cell Shape changes, down to the state of free energy minimum, together with estimation of the time needed for the resulting transport of water, revealed a complex, three-phase picture of temporal alterations in cellular geometry with a wide spectrum of final results, and led to propose a standard model of reticulocyte–erythrocyte Transformation. According to the model, both cell volume and surface undergo changes, and the work of the pressure, initially accumulated in the cytoskeleton, is consumed for local bending of the cell membrane. Further simulations with modified initial Shape or parameters of the standard model show the trajectories of system evolution and help in better understanding the conditions for the erythro-, sphero-, ovalo-, stomato-, and leptoidal metamorphosis of maturing red blood cells. The stability of the final biconcave Shape was also verified. Spherogenic modifications were discussed in the context of spherocytosis. Future development of the model was proposed.