Membrane protein distribution in composite polymer-lipid thin films

We present a model system to demonstrate that the positioning of biomolecules (membrane proteins) in a nonnative, complex thin film environment can be regulated by the phase behavior of film components. Partial separation between an amphiphilic polymer and a lipid drives the protein to a fluid phase, mechanically more similar to a cellular bilayer

Surface-Mediated Supramolecular Self-Assembly of Protein, Peptide, and Nucleoside Derivatives: From Surface Design to the Underlying Mechanism and Tailored Functions

Amongst the many parameters that have been explored to exercise control over self-assembly processes, the influence of surface properties on self-assembly has been recognized as important but has received considerably less attention than other factors. This is particularly true for biomolecule-derived self-assembling molecules such as protein, peptide or nucleobase derivatives. Due to their relevance for biomaterial and drug delivery applications, interest in these materials is increasing. As the formation of supramolecular structures from these biomolecule derivatives inevitably brings them into contact with surfaces of surrounding materials, understanding and control of the impact of the properties of these surfaces on the self-assembly process is important. In this review, we present an overview of the different surface parameters that have been used and studied for the direction of the self-assembly of protein, peptide and nucleoside-based molecules. The current mechanistic understanding of these processes will be discussed and potential applications of surface-mediated self-assembly will be outlined

Biomimetic Planar Polymer Membranes Decorated with Enzymes as Functional Surfaces

Functional surfaces were generated by a combination of enzymes with polymer membranes composed of an amphiphilic, asymmetric block copolymer poly­(ethyleneglycol)-<i>block</i>-poly­(γ-methyl-ε-caprolactone)-<i>block</i>-poly­[(2-dimethylamino)­ethylmethacrylate]. First, polymer films formed at the air–water interface were transferred in different sequences onto silica solid support using the Langmuir–Blodgett technique, generating homogeneous monolayers and bilayers. A detailed characterization of these films provided insight into their properties (film thickness, wettability, topography, and roughness). On the basis of these findings, the most promising membranes were selected for enzyme attachment. Functional surfaces were then generated by the adsorption of two model enzymes that can convert phenol and its derivatives (laccase and tyrosinase), well known as high-risk pollutants of drinking and natural water. Both enzymes preserved their activity upon immobilization with respect to their substrates. Depending on the properties of the polymer films, different degrees of enzymatic activity were observed: bilayers provided the best conditions in terms of both overall stability and enzymatic activity. The interaction between amphiphilic triblock copolymer films and enzymes is exploited to engineer “active surfaces” with specific functionalities and high efficacy resulting from the intrinsic activity of the biomolecules that is preserved by an appropriate synthetic environment

Planar Biomimetic Membranes Based on Amphiphilic Block Copolymers

Planar biomimetic membranes based on amphiphilic block copolymers represent artificial systems designed to mimic natural membranes but with improved stability and robustness to support applications in domains such as medicine and technology. Here we present methods to produce, characterize, and modify membranes based on amphiphilic block copolymers, with appropriate properties in order to combine them with biomolecules (enzymes, proteins, DNA) in a biomimetic strategy. We indicate both the advantages of using these membranes and the limitations one can encounter when working with planar membranes. While still in its early stage of research, development of planar artificial membranes decorated with biomolecules represents a novel strategy with high potential for valuable nanometer scale applications

High-Density Reconstitution of Functional Water Channels into Vesicular and Planar Block Copolymer Membranes

The exquisite selectivity and unique transport properties of membrane proteins can be harnessed for a variety of engineering and biomedical applications if suitable membranes can be produced Amphiphilic block copolymers (BCPs), developed as stable lipid analogs, form membranes that functionally incorporate membrane proteins and are ideal for such applications While high protein density and planar membrane morphology are most desirable, BCP-membrane, protein aggregates have so far been,limited to law protein densities in either vesicular or bilayer morphologies. Here, we used dialysis to reproducibly form planar and vesicular BCP membranes with a high density of reconstituted aquaporin-0 (AQP0) water channels. We show that AQP0 retains its biological activity when incorporated at high density in BCP membranes, and that the morphology of the BCP protein aggregates can be controlled by adjusting the amount of incorporated AQP0. We also show that BCPs can be used to form two-dimensional crystals of AQP0