Development of novel nanomaterials based on self-organising bacterial S-layer proteins

Nanoparticles attract great attention for the development of new materials since their properties usually differ significantly from those of the bulk material. They play a key role in future technologies and are used for the manufacturing of novel nanocatalysts, biosensors, for biomedical applications and nanoelectronic devices. The development of cluster-assembled materials with discrete, size-selected nanoparticles is of great interest to enable the fine-tuning of the properties of the nanoparticles. The use of self-assembling biological templates which allow the synthesis of a wide range of inorganic nanocrystals is a promising approach to produce arrays of nanoparticles in a simple way.
We present a unique interdisciplinary approach to produce arrays of nanoparticles of a defined size which posses magnetic, semiconducting, or catalytic properties. In this approach the proteinaceous self-assembling bacterial surface layers (S-layers) are used as biological templates. Most of the S-layers are composed of protein monomers with the ability to self-assemble into two-dimensional arrays. The regular distributed pores of these paracrystalline arrays work as binding sites for various metals such as Pt, Pd, Au, Fe, and offer ideal structures for the formation of regular distributed nanoclusters of a defined size [1]. Such arrays of inorganic nanoparticles as hybrids with self-assembling biological molecules, which possess a high stability [2], are very attractive for technical applications such as the development of novel catalysts, biomedical applications, the programmed assembly of nanometer scale electronic devices, and optical industry.

[1] Pollmann, K., J. Raff, M. Merroun, K. Fahmy, S. Selenska-Pobell. 2006. Metal binding by bacteria from uranium mining waste piles and its technological applications. Biotechnol. Adv. 24: 58-68.
[2] Fahmy, K., M. Merroun, K. Pollmann, J. Raff, O. Savchuk, C. Hennig, S. Selenska-Pobell. 2006. Secondary structure and Pd(II) coordination in S-layer proteins from Bacillus sphaericus studied by infrared and X-ray absorption spectroscopy. Biophys. J. 91: 996-1007.