Polymerized ABA Triblock Copolymer Vesicles

Nardin, Corinne; Hirt, Thomas; Leukel, Jörg; Meier, Wolfgang

doi:10.1021/la990951u

Cited by 459 publications

(479 citation statements)

References 28 publications

Supporting

Mentioning

455

Contrasting

Unclassified

Order By: Relevance

“…This size is consistent with similar PMOXA-PDMS-based block copolymers with different hydrophilic-to-hydrophobic block length ratios (26). Dividing the radius of gyration (R g ) from static light-scattering experiments by the hydrodynamic radius from dynamic light scattering yields a value close to one (R g /R h ϭ 1.03); this result is consistent with a hollow-sphere morphology (26).…”

Section: Resultssupporting

confidence: 81%

“…The composition of the symmetric triblock copolymer was poly(2-methyloxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyloxazoline) (PMOXA 15 -PDMS 110 -PMOXA 15 ). This ABA polymer has a larger hydrophobic block (110 dimethylsiloxane units)-to-hydrophilic block (15 methyloxazoline units) ratio than those tested in previous studies (18,19,(24)(25)(26)(27). The physical characteristics of the ABA triblock copolymer were studied by using microscopy techniques, whereas light scattering was used to characterize the permeability.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z

Kumar

Grzelakowski

Zilles

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

666

643

View full text Add to dashboard Cite

The permeability and solute transport characteristics of amphiphilic triblock-polymer vesicles containing the bacterial water-channel protein Aquaporin Z (AqpZ) were investigated. The vesicles were made of a block copolymer with symmetric poly-(2-methyloxazoline)-poly-(dimethylsiloxane)-poly-(2-methyloxazoline) (PMOXA 15-PDMS110-PMOXA 15) repeat units. Light-scattering measurements on pure polymer vesicles subject to an outwardly directed salt gradient in a stopped-flow apparatus indicated that the polymer vesicles were highly impermeable. However, a large enhancement in water productivity (permeability per unit driving force) of up to Ϸ800 times that of pure polymer was observed when AqpZ was incorporated. The activation energy (E a) of water transport for the protein-polymer vesicles (3.4 kcal/mol) corresponded to that reported for water-channel-mediated water transport in lipid membranes. The solute reflection coefficients of glucose, glycerol, salt, and urea were also calculated, and indicated that these solutes are completely rejected. The productivity of AqpZ-incorporated polymer membranes was at least an order of magnitude larger than values for existing salt-rejecting polymeric membranes. The approach followed here may lead to more productive and sustainable water treatment membranes, whereas the variable levels of permeability obtained with different concentrations of AqpZ may provide a key property for drug delivery applications.permeability ͉ triblock copolymer ͉ water treatment B iological membranes have excellent water transport characteristics, with certain membranes able to regulate permeability over a wide range. The permeability of membranes such as those present in the proximal tubules of the human kidney (1) can be increased by insertion of specific water-channel membrane proteins known as Aquaporins (AQPs). Other biological membranes, such as those in mammalian optic lenses (2), erythrocytes (3), and many other cell membranes (4) are constitutively AQP-rich. The permeabilities of AQP-rich membranes are orders of magnitude higher than those observed for unmodified phospholipid membranes (5). Additionally, some members of the AQP family have excellent solute retention capabilities for small solutes such as urea, glycerol, and glucose, even at high water transport rates (5, 6). These properties result from the unique structure of the water-selective AQPs. These AQPs have six membrane-spanning domains and a unique hourglass structure (7) with conserved charged residues that form a pore that allows both selective water transport and solute rejection. The AQP used in this study was a bacterial aquaporin from Escherichia coli, Aquaporin Z (AqpZ). AqpZ was selected because it can enhance the permeability of lipid vesicles by an order of magnitude while retaining small uncharged solutes (5). Additionally, AqpZ can be expressed in relatively large quantities in E. coli and has been reported to be quite stable under different reducing conditions and at temperatures of 4°C (5)-properties that make it att...

show abstract

Section: Resultssupporting

confidence: 81%

mentioning

confidence: 99%

Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z

Kumar

Grzelakowski

Zilles

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

666

643

View full text Add to dashboard Cite

show abstract

“…Monomer-aggregate equilibria with similar characteristics, where the monomer concentration is the critical aggregation concentration, are exemplified in work on liposomes and vesicles by Nardin et al (2000) and Chécot et al (2002).…”

Section: Aggregationmentioning

confidence: 99%

Characterisation of aggregates of cyclodextrin-drug complexes using Taylor Dispersion Analysis

Zaman

Bright

Adams

et al. 2017

International Journal of Pharmaceutics

View full text Add to dashboard Cite

There is a need to understand the nature of aggregation of cyclodextrins (CDs) with guest molecules in increasingly complex formulation systems. To this end an innovative application of Taylor dispersion analysis (TDA) and comparison with dynamic light scattering (DLS) have been carried out to probe the nature of ICT01-2588 (ICT-2588), a novel tumor-targeted vascular disrupting agent, in solvents including a potential buffered formulation containing 10% hydroxypropyl-betacyclodextrin. The two hydrodynamic sizing techniques give measurement responses are that fundamentally different for aggregated solutions containing the target molecule, and the benefits of using TDA in conjunction with DLS are that systems are characterised through measurement of both mass-and z-average hydrodynamic radii. Whereas DLS measurements primarily resolve the large aggregates of ICT01-2588 in its formulation medium, methodology for TDA is described to determine the size and notably to quantify the proportion of monomers in the presence of large aggregates, and at the same time measure the formulation viscosity. Interestingly TDA and DLS have also distinguished between aggregate profiles formed using HP-beta-CD samples from different suppliers. The approach is expected to be widely applicable to this important class of drug formulations where drug solubility is enhanced by cyclodextrin and other excipients. To: The Editor, International Journal of Pharmaceutics From: Rob Forbes and David GoodallWe have revised the manuscript to reflect the amendments of the reviewers. The original cover letter is below.We are submitting this article, which describes novel work showing benefits of use of Taylor dispersion analysis in conjunction with dynamic light scattering to characterize ICT01-2588, a tumour-targeted vascular disrupting agent, in a potential formulation medium containing 10% hydroxypropyl--cyclodextrin as a solubility enhancing agent. Our approach is expected to be widely applicable to this important class of drug formulations where drug solubility is enhanced by cyclodextrin and other excipients, and is a contribution to advancing an understanding of the nature of self-assembly in such complex systems.The lead reviwer suggested is Thorsteinn Loftsson, who is a member of your Editorial Advisory Board. We cite a number of his papers. Of the other suggested referees. We cite work on Taylor dispersion analysis by the other two proposed referees, Ana Ribeiro and Jesper Ostergaard, and Robert HoylstPlease note that if possible we would like to name two corresponding authors, Robert T. Forbes (lead corresponding author) and David M. Goodall (second corresponding author). If this is not possible, it should be just Robert T. Forbes. The bulk of this work was conducted whilst Professor Forbes was at the University of Bradford, which is listed as his affiliation #1. He is currently at the University of Central Lancashire, which is listed as affiliation #2.Regarding declaration of conflict of interest guidelines, please note the foll...

show abstract

“…Crosslinked di-and triblock copolymer vesicles can be used to prepare hollow nanospheres for the controlled release of an encapsulated drug in the bloodstream. 4,5 Channel-forming transmembrane proteins have been incorporated within triblock copolymer planar membranes 6 and vesicles. 7 Responsive nanocapsules can be fabricated containing these DENNIS E. DISCHER Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Computer simulation of aqueous block copolymer assemblies: Length scales and methods

Ortiz

Nielsen

Klein

et al. 2006

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

Atomistic, coarsegrain, and mesoscopic computer simulation methods applied recently to the study of block copolymer assemblies in solution are reviewed. At the atomic level, particle-based simulations have provided insight into specific interactions such as hydrogen bonding between polymer and water.Coarse-grain models have given a generalized view of the conformations of polymer chains in solvents of different qualities by grouping clusters of atoms into effective interaction sites. Mesoscopic selfconsistent field theory allows for the study of the phase diagram of block copolymers in water using a mean-field continuum description. [1907][1908][1909][1910][1911][1912][1913][1914][1915][1916][1917][1918] 2006 Keywords: all-atom; coarse-grain; DPD; field theory; molecular dynamics Kingston, ON in 1996. In 1998, he received his M.Sc. and Ph.D. degrees from the University of Toronto for his work on the statistical mechanics of mixed quantum-classical systems under the supervision of Raymond E. Kapral. He then moved on to join the group of Michael L. Klein at the University of Pennsylvania as a postdoctoral research associate to work on coarse-grain models of membranes. His current research interests are on the solubilization of carbon nanotubes by cyclic peptides and on a detailed molecular understanding of colloidal stability.

show abstract

Polymerized ABA Triblock Copolymer Vesicles

Cited by 459 publications

References 28 publications

Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z

Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z

Characterisation of aggregates of cyclodextrin-drug complexes using Taylor Dispersion Analysis

Computer simulation of aqueous block copolymer assemblies: Length scales and methods

Contact Info

Product

Resources

About