Easy characterization of SERS substrates of enzymatically produced silver nanoparticles and their applications in the area of bioanalytics

The broad application of surface-enhanced Raman spectroscopy (SERS) is greatly hampered by the lack of reliable and reproducible substrates; usually the activity of a given substrate has to be determined by time-consuming experiments such as calibration studies or ultramicroscopy. To use SERS as a standard analytical tool, cheap and reproducible substrates are required, preferably characterizable with a technique that does not interfere with the subsequent measurements. Here, we introduce an innovative approach to produce low cost and large scale reproducible substrates for SERS applications, which allows an easy and economical production of micropatterned SERS active surfaces based on an enzyme induced growth of silver nanostructures. The special structural feature of the enzymatically deposited silver nanoparticles prevents the breakdown of SERS activity even at high particle densities and exhibits a relationship between electrical conductivity and resulting SERS activity of a given spot. This enables the prediction of the SERS activity of the nanostructure ensemble and therewith the controllable and reproducible production of SERS substrates of enzymatic silver nanoparticles on a large scale. Furthermore, the presented substrate shows a high reproducibility and is appropriate for various applications.