Daniel Stadler1 Shifaa Siribbal1 Isabel Gessner1 Senol Oez1 Shaista Ilyas1 Sanjay Mathur1

1, University of Cologne, Cologne, , Germany

The demands for materials which integrate more than one functional imaging or therapeutic unit are of increasing interest for biomedical applications. Here, we present the step-by-step preparation of asymmetric and optically active particles, namely Gd2O3@Ag, Gd2O3@Au, SiO2-N3@Au and SiO2-SH@Au via simple magnetron sputtering approach. Successful attachment of plasmonic nanoparticles to the surface of metal oxide spheres without necessity of a potentially toxic inter-adhesive layer was proven by optical methods as well as X-ray photoelectron spectroscopy. The combination of optical and magnetic properties as present inGd2O3@Ag and Gd2O3@Au Janus-type particles leads to dual-imaging probes for optical and magnetic resonance imaging. In addition, functional groups, such as azide groups were linked to the surface of silica particles previous to Au nanoparticle attachment. Subsequent side-selective click reactions with 5-FAM were successfully performed as demonstrated by UV-vis measurements. All described systems exhibited excellent long-term stability and can therefore be considered as promising candidates for theranostic applications.