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Biofilm formation on implant materials causes a common problem: resistance to aggressive pharmacological agents as well as host defenses. Therefore, to reduce bacterial adhesion to implant surfaces we propose to use silver(I) coordination networks as it is known that silver is the most powerful antimicrobial inorganic agent. As a model surface, self-assembled monolayers (SAMs) on gold Au(111) was used to permit permanent attachment of our silver(I) coordination networks. The surface coatings showed typical nano-structured surfaces with a good biocompatibility for soft-tissue integration with fibroblast cells.

The system AgNO3 and L (L = ethanediyl bis(isonicotinate)) yielded so far five different compounds from a THF/H2O mixture (or acetonitrile) when reacted in a ratio 1:1. Three solvent-free compounds possess the same chemical composition, [Ag(L)NO3], but different structures and thus different properties. Additionally, two solvates [Ag(L)NO3] · nH2O with one or two water molecules have been identified. One of the solvates can be reversibly transformed into one of the solvent free compounds. This clay-like property depends strongly on the structure observed in the solid state, namely on the coordinating function of the nitrate ions with respect to silver cations. © 2006 Elsevier B.V. All rights reserved.

Varying the polyethyleneglycol spacer between two (iso)-nicotinic groups of the ligand systems, a large structural variety of silver coordination compounds was obtained, starting with zero-dimensional ring systems, via one-dimensional chains, helices and double-helices to two-dimensional polycatenanes. Theoretical calculations help to understand their formation and allow predictions in some cases. These structures can be tuned by careful design of the ligand, the use of solvent and the counter ions, influencing also other important properties such as light stability and solubility. The latter is important in the context of biomedical applications, using silver compounds as antimicrobial agents.

Split-and-mix libraries are an excellent tool for the identification of peptides that induce the formation of Ag nanoparticles in the presence of either light or sodium ascorbate to reduce Ag(+) ions. Structurally diverse peptides were detected in colorimetric on-bead screenings that generate Ag nanoparticles of different sizes, as confirmed by SEM and X-ray powder diffraction studies.