SERS platforms for high density DNA arrays

Abstract

Surface Enhanced Raman Scattering (SERS) gives rise to analytical applications with much promise. In our approach three steps are necessary. We require a SERS platform of high enhancement. This has been achieved using the special technique of Island Lithography, combined with Ag deposition by galvanic exchange, yielding an enhancement factor of 10(8). Probe oligonucleotide molecules are attached to a specific area on the platform, at the optimized surface concentration, using thiolated single stranded (ss) DNA molecules. The optimum surface concentration has been determined and interpreted in the light of the polyelectrolyte behaviour of ssDNA. Finally the change in SERS produced by hybridisation of the probe molecules to a target DNA molecule is measured. Highly discernible changes have been obtained. No change in probe signal is seen when presented with one base mismatched target. From this work it is concluded that the prospects for label-free DNA detection in high-density arrays is now close to achievement.

Multiple Surface Plasmon Resonances and Near-Infrared Field Enhancement of Gold Nanowells

“…44 We do not observe signals from other species including 11-mercaptoundecanoic acid and the bases of the nucleotide itself. In contrast, the spectrum obtained from sso2 peaks at 650 and 1570 cm -1 were attributed to G, 732 and 1320 cm -1 to A, 1023 and 1635 cm -1 to C, whereas the peak at 790 cm -1 corresponds to both C and T. 45 Although it was possible to reconstruct the composition of the oligonucleotide in a qualitative manner, quantification of signal intensities still awaits further investigation. Plotting the counts at 1588 cm -1 (Cy3) and those at 790 cm -1 (C and T) as a function of 1/A retained a linear relationship (data not shown), confirming potential suitability of Au NWs for analytical applications using SERS.…”

DNA detection using nanostructured SERS substrates with Rhodamine B as Raman label

“…In all cases, the immersion was lasted for 6 h or longer. and Deckert, 2006;Green et al, 2006), those two peaks may be connected with the bases of the PNA, indicative of its sequence and length. As for other samples i.e.…”

“…The SERS detection of various bio-molecules or species has been reported, such as proteins (Driskell et al, 2007), enzymes (Ruan et al, 2006), viruses , bacteria (Jarvis et al, 2006), cancer marker (Gong et al, 2007), and nucleotides (Nie and Emory, 1997;Kneipp et al, 1998Kneipp et al, , 1999Sackmann and Materny, 2006). Among those kinds of application, the detection of nucleotides or DNA is very interesting because the nucleotide bases show welldistinguished SERS peaks while the sugar or phosphate groups on the backbone have little interference (Green et al, 2006). The direct detection of DNA sequence at low concentration with SERS, however, is still elusive (Wu et al, 2006).…”

Nanostructures and nanostructured substrates for surface—enhanced Raman scattering (SERS)

“…Recent reviews of this topic with a particular focus on the applications of these structures are available. 91,92 Furthermore, lithography procedures followed by electro-deposition of metals can fabricate elaborate repeating structures, such as pillars 93 and torroids, 94 again with relatively long-range order. In these particular structures, island lithography involving the self-organisation of caesium chloride thin films into a disordered array of hemispherical islands has been used instead of electron-beam lithography or other 'beam writing' procedures.…”