Raman spectroscopy is a valuable tool in various research fields. The technique yields structural information from all kind of samples often without the need for extensive sample preparation. Since the Raman signals are inherently weak and therefore do not allow one to investigate substances in low concentrations, one possible approach is surface-enhanced (resonance) Raman spectroscopy. Here, rough coin metal surfaces enhance the Raman signal by a factor of 10(4)-10(15), depending on the applied method. In this review we discuss recent developments in SERS spectroscopy and their impact on different research fields.

The growing interest in DNA diagnostics is addressed today by microarrays with fluoresence detection. In our approach, we utilize spatially defined arrays of short oligonucleotides on a modified glass surface. Surface enhanced resonance Raman scattering (SERRS) is used to obtain molecularly specific spectra of the Raman-active dye-labeled DNA. Nanoparticles produced by enzymatic silver deposition are used as SERS-active substrate. They grow directly on the modified oligonucleotides and only in the spatially defined areas on the chip. Furthermore, they potentially offer several advantages for SERS detection. The nanoparticles are characterized and their ability for use as SERS- and SERRS-active substrate is estimated. Three different Raman-active dyes are investigated for their potential for involvement in sequence specific DNA analysis.

Traditional SERS active substrates are roughened metal electrodes, metal layers or metal colloids. Within this contribution nanoparticles produced by enzymatic silver deposition are utilized. These nanoparticles grow directly on the modified oligonucleotides and only in spatially defined areas on the chip surface. The applied biotin coupling system requires only a standard modification of the oligonucleotide, which is simple, stable and cost-effective in comparison to the usually used thiol modification. Furthermore they offer several advantages for SERS detection. The nanoparticles are characterized and their potential for their use as SERS active substrate and the potential for sequence specific DNA analysis is estimated. '''