Eur. Phys. J. E 4, 403-410
Amphiphilic block copolymer nanocontainers as bioreactorsC. Nardin1, J. Widmer1, M. Winterhalter2 and W. Meier1
1 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
(Received 22 August 2000)
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