Microarray-based detection of dye-labeled DNA by SERRS using particles formed by enzymatic silver deposition.

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.