Eur. Phys. J. E 4, 403-410
Amphiphilic block copolymer nanocontainers as bioreactors
C. Nardin1, J. Widmer1, M. Winterhalter2 and W. Meier11 Department of Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
2 Institut de Pharmacologie et de Biologie Structurale, CNRS, 205 route de Narbonne, F-31077 Toulouse, France
wolfgang.meier@unibas.ch
(Received 22 August 2000)
Abstract
Self-assembly of an amphiphilic triblock copolymer carrying polymerizable
end-groups is used to prepare nanometer-sized vesicular structures in
aqueous solution. The triblock copolymer shells of the vesicles can be
regarded as a mimetic of biological membranes although they are 2 to 3 times
thicker than a conventional lipid bilayer. Nevertheless, they can serve as a
matrix for membrane-spanning proteins. Surprisingly, the proteins remain
functional despite the extreme thickness of the membranes and that even
after polymerization of the reactive triblock copolymers. This opens a new
field to create mechanically stable protein/polymer hybrid membranes. As a
representative example we functionalize (polymerized) triblock copolymer
vesicles by reconstituting a channel-forming protein from the outer cell
wall of Gram-negative bacteria. The protein used (OmpF) acts as a
size-selective filter, which allows only for passage of molecules with a
molecular weight below 400 g mol-1. Therefore substrates may still
have access to enzymes encapsulated in such protein/polymer hybrid
nanocontainers. We demonstrate this using the enzyme 
-lactamase
which is able to hydrolyze the antibiotic ampicillin. In addition, a
transmembrane voltage above a given threshold causes a reversible gating
transition of OmpF. This can be used to reversibly activate or deactivate
the resulting nanoreactors.
83.70.Hq - Heterogeneous liquids: suspensions, dispersions, emulsions, pastes, slurries, foams, block copolymers, etc..
81.05.Ys - Nanophase materials.
87.68.+z - Biomaterials and biological interfaces.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
