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  - GEN
A1  - Georgiev, Vasil N.
A1  - Grafmüller, Andrea
A1  - Bléger, David
A1  - Hecht, Stefan
A1  - Kunstmann, Ruth 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
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 733 
KW  - azobenzene
KW  - lipid membranes
KW  - molecular dynamics
KW  - photoswitch
KW  - vesicles
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426298
SN  - 1866-8372
VL  - 5
IS  - 733
ER  - 
TY  - JOUR
A1  - Goulet-Hanssens, Alexis
A1  - Rietze, Clemens
A1  - Titov, Evgenii
A1  - Abdullahu, Leonora
A1  - Grubert, Lutz
A1  - Saalfrank, Peter
A1  - Hecht, Stefan
T1  - Hole Catalysis as a General Mechanism for Efficient and Wavelength-Independent Z -> E Azobenzene Isomerization
JF  - CHEM
N2  - Whereas the reversible reduction of azobenzenes has been known for decades, their oxidation is destructive and as a result has been notoriously overlooked. Here, we show that a chain reaction leading to quantitative Z -> E isomerization can be initiated before reaching the destructive anodic peak potential. This hole-catalyzed pathway is accessible to all azobenzenes, without exception, and offers tremendous advantages over the recently reported reductive, radical-anionic pathway because it allows for convenient chemical initiation without the need for electrochemical setups and in the presence of air. In addition, catalytic amounts of metal-free sensitizers, such as methylene blue, can be used as excited-state electron acceptors, enabling a shift of the excitation wavelength to the far red of the azobenzene absorption (up to 660 nm) and providing quantum yields exceeding unity (up to 200%). Our approach will boost the efficiency and sensitivity of optically dense liquid-crystalline and solid photo-switchable materials.
Y1  - 2018
U6  - https://doi.org/10.1016/j.chempr.2018.06.002
SN  - 2451-9294
VL  - 4
IS  - 7
SP  - 1740
EP  - 1755
PB  - Cell Press
CY  - Cambridge
ER  -