A selective colorimetric system for detecting O6-alkyl-deoxyguanosine adducts is described. In preliminary studies we synthesized a new nucleoside analog (dPer) that forms a stable base pair with O6-BnG. Au nanoparticles, which are functionalized with alkanethiol-capped oligonucleotides containing dPer complex a 13-base oligonucleotide target.  Hybridization of the target with the probes results in the aggregation of the nanoconjugates, which triggers a red to purple color change in solution. We evaluated spectroscopically the thermostability of Au-oligonucleotide nanoconjugates containing Per paired opposite an O6-BnG adduct in comparison with control sequences. The aggregates exhibit sharp absorbance transitions which allow one to distinguish adduct containing target sequences from those containing canonical bases. Furthermore, when test solutions are incubated at different temperatures they have different colors according to the differential stability of the aggregates. Thus, the synthetic nucleoside dPer in combination with Au nanoparticles can be used for the colorimetric detection of O6-BnG adducts.

Nanoprobes for detecting DNA adducts

244th National Meeting (2012)

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