TY  - JOUR
A1  - Georgiev, Vasil N.
A1  - Grafmüller, Andrea
A1  - Bléger, David
A1  - Hecht, Stefan
A1  - Kunstmann, Sonja
A1  - Barbirz, Stefanie
A1  - Lipowsky, Reinhard
A1  - Dimova, Rumiana
T1  - Area increase and budding in giant vesicles triggered by light
BT  - behind the scene
JF  - Advanced science
N2  - Biomembranes are constantly remodeled and in cells, these processes are controlled and modulated by an assortment of membrane proteins. Here, it is shown that such remodeling can also be induced by photoresponsive molecules. The morphological control of giant vesicles in the presence of a water-soluble ortho-tetrafluoroazobenzene photoswitch (F-azo) is demonstrated and it is shown that the shape transformations are based on an increase in membrane area and generation of spontaneous curvature. The vesicles exhibit budding and the buds can be retracted by using light of a different wavelength. In the presence of F-azo, the membrane area can increase by more than 5% as assessed from vesicle electrodeformation. To elucidate the underlying molecular mechanism and the partitioning of F-azo in the membrane, molecular dynamics simulations are employed. Comparison with theoretically calculated shapes reveals that the budded shapes are governed by curvature elasticity, that the spontaneous curvature can be decomposed into a local and a nonlocal contribution, and that the local spontaneous curvature is about 1/(2.5 mu m). The results show that exo- and endocytotic events can be controlled by light and that these photoinduced processes provide an attractive method to change membrane area and morphology.
KW  - azobenzene
KW  - lipid membranes
KW  - molecular dynamics
KW  - photoswitch
KW  - vesicles
Y1  - 2018
U6  - https://doi.org/10.1002/advs.201800432
SN  - 2198-3844
VL  - 5
IS  - 8
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Brosnan, Sarah M.
A1  - Schlaad, Helmut
A1  - Antonietti, Markus
T1  - Aqueous Self-Assembly of Purely Hydrophilic Block Copolymers into Giant Vesicles
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Self-assembly of macromolecules is fundamental to life itself, and historically, these systems have been primitively mimicked by the development of amphiphilic systems, driven by the hydrophobic effect. Herein, we demonstrate that self-assembly of purely hydrophilic systems can be readily achieved with similar ease and success. We have synthesized double hydrophilic block copolymers from polysaccharides and poly(ethylene oxide) or poly(sarcosine) to yield high molar mass diblock copolymers through oxime chemistry. These hydrophilic materials can easily assemble into nanosized (<500nm) and microsized (>5m) polymeric vesicles depending on concentration and diblock composition. Because of the solely hydrophilic nature of these materials, we expect them to be extraordinarily water permeable systems that would be well suited for use as cellular mimics.
KW  - block copolymers
KW  - polymersomes
KW  - polysaccharides
KW  - self-assembly
KW  - vesicles
Y1  - 2015
U6  - https://doi.org/10.1002/anie.201502100
SN  - 1433-7851
SN  - 1521-3773
VL  - 54
IS  - 33
SP  - 9715
EP  - 9718
PB  - Wiley-VCH
CY  - Weinheim
ER  -