A basis for molecular factories: multifunctionality and immobilization of biomolecule-polymer assemblies

Bio-inspired planar polymer membranes are synthetic membranes designed to be combined with biomolecules such as proteins, enzymes or peptides. These membranes provide both an increased mechanical stability as well as an environment to preserve the functionality of the biomolecules. In this thesis, two different kinds of planar membrane systems are demonstrated. In the first project, a sensor for phenolic compounds based on a bio-inspired polymer membrane was developed. Functional surfaces were generated by combining enzymes with polymer membranes composed of an amphiphilic, asymmetric block copolymer. Firstly, polymer films which were formed at the air-water interface were transferred onto silica solid support, by using the Langmuir-Blodgett method. The films were characterized according to their properties, including film thickness, wettability, topography, and roughness. The most promising membranes were used for enzyme attachment. Two model enzymes, laccase and tyrosinase, were adsorbed to the surface and their activity regarding the conversion of phenolic compounds was measured. This project is described in Chapter 1 in detail. In the second project, the interaction of the model pore-forming peptide melittin was studied in combination with a planar synthetic membrane. The investigation focused the interaction of melittin with amphiphilic block copolymer-based synthetic planar membranes as well as the insertion of melittin into these membranes to induce pore formation. Some specific molecular properties of the block copolymers and of the resulting membranes were selected for the investigation, such as hydrophilic to hydrophobic block ratio, membrane thickness and surface roughness. Through melittin addition to the synthetic membranes, melittin insertion requirements were better understood. This project is described in Chapter 2 in detail. Each chapter contains a separate introduction, material and methods section and conclusion and outlook specific to the project.20
In summary, in this thesis the properties of different combinations and applications of polymer-based membranes with biomolecules were investigated to a deeper level.