Metal Cluster Deposition on S-Layer Templates - Basic Mechanism and Possible Application

Wolfgang Pompe, Lucio C. Ciacchi, Alexander Kirchner, Michael Mertig, and Reiner Wahl

Institute of Materials Science, Dresden University of Technology, Hallwachsstr. 3, D-01602 Dresden, Germany



Bacterial membranes can be used as smart templates for the preparation of self-assembling metallic nanostructures. S-layer sheets isolated from Sporosarcina ureae and from Bacillus sphaericus have been applied successfully for manufacturing of membranes functionallized with nanoscale metal clusters.

The deposition of platinum, palladium, and silver clusters from the aqueous solution has been governed by selective adsorption in the pore channels of the protein surface. A precipitation/dissolution process with a sticking probability P<1 yields a cluster array of high periodicity. Alternatively, the cluster growth can be stimulated by electron irradiation of activated S-layers too. The formed metal clusters have been characterised by high resolution transmission electron microscopy showing a very small size distribution and a closed packed, quasi periodic distribution in the S-layer pores. Ab initio molecular dynamics simulation can be used to understand the initial stage of cluster formation. The self-assembling metallic nanostructures offer challenging options for new approaches in catalysis, and nanoscale sensors development.