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Generation of composites from borides with tuneable electrical conductivities using peptides optimized by genetic engineering; characterization of the bio-solid interactions by modelling and AFM

Barbara Albert, Kathrin Hofmann, Carina Martschinke
Robert Berger
Robert Stark, Christian Dietz, Limor Zemel
Nico van der Vegt, Timir Hajari
TU Darmstadt

 

in collaboration with
Bernhard Hauer, Sandra Facey, Martin Ploss
Universität Stuttgart 

 

An interaction of inorganic materials with peptides shall be created in a chemobiological composite of phages and boride particles. Binding properties are to be optimized by genetic engineering which will employ a screening system based on biopanning specific peptides with preferences for different borides with different physical properties. Two model systems are used: 1) for a start a metallic, magnetic boride in form of wet-chemically synthesized nanoparticles 2) later on a boron-rich ceramic which is very high-temperature stable and inert.

The key factors determining the preference of these peptides for a certain material shall be determined by molecular simulation. With the help of quantum chemical calculations, force fields for solid surfaces and solvents and peptides in contact with these surfaces are to be developed. Quantification will be performed experimentally by atomic force microscopy. The peptide-modified borides will be analysed for their magnetism and electrical conductivity, as well as thermal stability. This requires the modification and adjustment of established methods of physical properties measurements to composite samples. Later, the system will be modified for ceramic borides and specific peptides shall be developed for these as well. Bifunctional phages with differently optimized peptides might be used to combine different metallic and semiconducting borides or both metallic and ceramic inorganics into nano- and micro-structured composites with unforeseeable properties. We also envision small proteins consisting of different peptide sequences each optimized for a specific inorganic material. This way a well-defined spatial orientation of functional materials may be achieved. Basic knowledge gained from a joint experimental and theoretical study of bonding interactions between peptides and boride materials is crucial for further development of smart materials based on non-oxide solids. It can potentially pave the way for a wealth of applications such as thermoelectric devices, field effect transistors or biomedical systems. The project builds on the strong interaction between researchers from molecular biology and solid state chemists, as well as theoretically working groups and experts on atomic force microscopy.