Detailed Infromation on Bio-Related Materials

Bio-Related Materials represent the most complex type of matter studied at MAINZ. In this area, we address three main materials classes. Bio-mimetic materials represent a class of materials that we design by “learning from nature”. Studying these materials helps to understand generic phenomena and processes in real biomaterials. This eventually allows for designing new materials with enhanced properties. Bio-hybrid structures formed by a combination of syntheticand natural constituents are investigated to exploit the exceptional recognition capabilities ofbiological molecules. As a new research activity, we also include materials for bio-medicalapplications.

Nature is still far ahead of technology with respect to the design of materials. This is especially shown by natural materials with extreme mechanical properties, smart responsive materials, or materials which interact with high specificity. Furthermore, many important applications of advanced materials involve the interaction of materials with living organisms. In recent years, the research activity at MAINZ on bio-related materials has increased substantially, and this trend is expected to continue. Activities in this area were pioneered in the context of CRC625. Also, recent research has led to the submission of a new CRC proposal (CRC1066) “Nanodimensional polymeric therapeutics for tumor therapy”, involving many MAINZ PIs (Frey, Landfester, Tremel, Schmid, Schmidt, Zentel).

The Master program “Materials Science” (to be established at JGU) also includes the topic of bio-related materials in its curriculum. The existing highly successful Bachelor and Master program “Biomedical Chemistry” has already demonstrated the attractiveness of a teaching program with closely linked medical, biological, and materials science aspects.

Studying bio-mimetic model systems helps to gain an improved understanding of biological materials, because of their reduced complexity and tunable properties. As one example, controlled transport through cell membranes is essential for many processes in life. Consequently, studying model systems for investigating such transport mechanisms constitutes one important topic of experimental and theoretical bio-mimetic materials research at MAINZ. We focus on mechanisms that do not rely on specific channel proteins. By simulations, we investigate whether and how polymers can be used to induce transient pores in lipid membranes (Schmid). Experimentally, transport of fluorescently-labeled drugs through membranes are monitored by fluorescence correlation spectroscopy (Butt). A second, closely related research topic addresses the mechanisms leading to selective interactions of nanoobjects (proteins, functionalized nanoparticles, polymers) with heterogeneous membranes. Nature presumably uses selective interactions to achieve close control over important transport processes, e.g., in signal transduction. Simulations deal with molecular recognition on patched surfaces or bilayers, and search for key-lock motifs (Schmid). A first experimental study has reported pattern formation due to segregation of lipid bilayers comprised partly of fluorinated lipids with glycopeptidic recognition sites (Hoffmann-Röder,Zentel).

By imitating nature, bio-mimetic materials helps to rationally design synthetic materials with improved and tailored properties. One prominent example from MAINZ are super-hydrophobic surfaces mimicking the lotus effect to obtain, e.g., self-cleaning surfaces, which are generated by deposition of hybrid core-shell particles (Butt). Bio-mimetic active surfaces represent another major example, where we make use of smart adhesive properties to tailor adhesion and detachment froma surface (del Campo).

Bio-hybrid structures are new materials, which contain synthetic as well as biological constituents (peptides, DNA or RNA fragments). They take advantage of the unique structure and function of biological molecules. Bio-hybrid structures include bio-mimetic -biological hybrid structures as well as synthetic-biological hybrid structures, which exploit the specific recognition capabilities of biological molecules (Heinze, Frey, Müllen, Paulsen, Schmidt). For instance, recombinant elastinlike proteins have been successfully conjugated to oligonucleotides for specific self-assembly by hybridization of complementary oligonucleotide strands. The same principle was applied to di- and triblock copolymers consisting of a synthetic block and one or two nucleotides, which act as specific recognition sites for supramolecular structure formation (Müllen).

As another example, MAINZ PIs have created biological hybrid complexes of the lightharvesting complex from the photosynthesis apparatus in plants and organic dyes and/or semiconductor nanoparticles (Basché, Müllen, Paulsen). In the resulting hybrid complex, the chemical and electronic interactions were studied aiming at introducing nature‘s highly efficient concept of light harvesting into photovoltaic energy devices. Besides covalently connected structures, biological hybrid structures can be formed by complexation of biological templates such as DNA with dyes (Müllen) and surfactants (Schmidt). Complexation can be utilized for directed self-assembly where the topology of the complexes is predetermined by the biological constituent. Another application is to use protein-surfactant complexes to elucidate the functional structure of proteins (Research Highlight 12).

Future research makes use of the specific recognition capability of biological constituents to Rationally Design even more complex materials. An example for these materials are multi blockcopolymers with a perfectly defined large number of blocks (>10) consisting of various synthetic polymers and/or polypeptides and DNA (Schmidt). Proteins and enzymes may also constitute unique building blocks in order to prepare novel bio-hybrid structures (Frey, Schmidt, Tremel).

An important line of activity in MAINZ is devoted to developing materials for bio-medical applications with useful Function-through-Structure. Here, one focus lies on designing molecules or nanostructures that can be employed for drug transport, controlled release, and related applications. These structures comprise bio-compatible and bio-degradable polymers (Frey, Zentel), polymer-protein/antibody and polymer-drug conjugates (Frey, Landfester, Schmidt, Zentel) polyelectrolyte complexes for DNA transfection (Müllen, Schmidt) as well as dye and radioactively labeled polymers and inorganic nanoparticles for in vitro- and in vivo-imaging (Müllen, Tremel,Zentel). The emerging field of polymer therapeutics requires bio-compatible and bio-degradable polymers with a large variety of orthogonally-protected functional groups. Investigations comprise polymer-protein conjugates (Frey) and polymer-antibody conjugates for specific tumor targeting (Frey, Schmidt, Zentel). The concept of polyvalent interaction extends to multishell particles for controlled drug delivery (Landfester, Tremel). Such multi-shell particles need to possess a defined number of multiple chemotherapeutic agents connected via releasable bonds, internal spacers for increased biocompatibility, and multivalent transporter sites intended to aidcellular uptake.

Teaching, learning and training opportunities

Bio-related materials require a deep understanding of biological function combined with the ability to use or mimic biological materials by synthetic approaches. Scientists who work in this area not only need characterization and theory skills (in soft matter and solid state physics) as well as organic synthesis, but also need biochemical knowledge and skills. Our combined theoretical and experimental approach allows us to understand the complexity of bio-related materials. On this basis, we can comprehend the circumstances in which biological systems function, to eventuallyutilize them. Reduction of complexity of bio-related materials will allow us to generalize insight and generate ideas for new synthetic materials. Finally, fabricating bio-related materials opens a range of complex Processing training opportunities. Training in this research area complements the activities of the graduate school TRANSMED, because MAINZ focuses on the biochemical aspects, while TRANSMED covers relevant medical aspects.

Connection to other research areas of MAINZ

Research on Bio-Related Materials starts at the single-molecule level and proceeds by addressing several levels of hierarchical organization, which are treated in the other research areas. Many of the uses of materials for bio-medical applications depend on new Functional Polymers. Someof the single-molecule characterization techniques that were developed for the investigation of molecules and functional polymers can be applied to bio-related materials, e.g., plasmonresonance sensors (Sönnichsen), microcantilever and surface force techniques (Butt). New state-of-the-art facilities, for instance soft advance X-ray spectroscopy (Schönhense), are used to study the structure and dynamics of aggregates such as light harvesting complexes, both experimentally (Paulsen) and theoretically (Kremer). Individual aspects of structure and dynamics in biological matter can often be analyzed more easily by simplified bio-related Model Systems. As in all other research areas, multiscale modeling approaches are necessary to gain insight at more precise quantitative level (Kremer). Particularly close connections exist to the research area Hybrid Structures, where biological molecules and bio-inspired conceptsare often used.