CONICET | Buscador de Institutos y Recursos Humanos

Nanomaterials-based devices as platforms for sensors and biosensors that can improve detection capabilities and/or anchor the active element of the device to the metal surface without degradation are key elements for many promising applications. In this work we present two easy and novel methods in order to solve these problems. Thiols on Au surfaces have been proposed as basic units in molecular electronics, as building blocks in sensing and biorecognition devices, in actuators and molecular motors among others. However, degradation of thiolate self-assembled monolayers (SAMs) in ambient conditions and liquid environments seriously limits the fabrication of thiol-based devices. Here, we demonstrate that nanostructured gold exhibits higher resistance to SAM degradation in relation to polycrystalline preferred oriented Au(111). The nanostructured Au is an interesting platform because it can be easily prepared, has surface enhanced Raman spectroscopy (SERS) activity, and exhibits a high signal/noise ratio for amperometric detection because of its large real surface area. On the other hand, the search of appropriate substrates as platforms for SERS ultrasensitive detection of biomolecules has resulted in an enormous field of research. Typically Au cavity void metallic arrays can be grown with better reproducibility, homogeneity, and stability, while Ag structures display significantly larger SERS enhancements. To exploit these two apparently excluding aspects, quality and enhancement, we report a detailed study of 500 nm Au-nanocavity templates modified by the controlled electrochemical deposition of 100 Ag layers. These results provide a general platform for the preparation of renewable SERS-active substrates.