Fabrication of highly oriented nanocluster arrays by biomolecular templating

The formation of highly oriented cluster arrays by chemical deposition of platinum onto a regular 2D protein template is studied. The crystalline bacterial surface layer (S layer) of Sporosarcina ureae exhibiting a p4 symmetry with a lattice spacing of 13.2 nm is used as the protein template. Cluster deposition onto the S layer is achieved by chemical reduction of a platinum salt. The growth kinetics of the clusters has been examined by UV-VIS spectrometry. Transmission electron microscopy reveals the formation of well separated metal clusters with an average diameter of 1.9 +/- 0.6 nm. The lateral cluster arrangement is defined by the underlying protein crystal. We observe 7 cluster sites per unit cell corresponding to a density of 4 x 10(12) cm(-2). They are located in the nano-sized pores and gaps of the crystalline S layer.