Extrinsic NA Detection Using Hybridization

The extrinsic DNA hybridization scheme (Vo-Dinh et al. 1999, 2006) is depicted in Fig. 5.6. It consists of several steps (a) selection of a suitable label providing high SERS signal, (b) DNA probe sequence is labelled with label providing high SERS signal, (c) the oligonucleotide with a complementary base sequence is immobilized at the SERS-active substrate and (d) the hybridization of the labelled DNA probe 

One possibility to enhance the sensitivity of SERRS probes for DNA detection is a controlled DNA-based self-assembly of dye-labelled oligonucleotide-functionalized Ag NPs (Graham et al. 2008). The Ag NP coated with a monolayer of benzotriazoles is incubated with two different, noncomplementary 5 -thiol-functionalized oligonucleotide sequences. Hybridization occurs when a target sequence complementary to both sequences is added to the dye-functionalized DNA/(Ag NP) conjugates. 

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