Scanometric DNA array detection with nanoparticle probes

A method for analyzing combinatorial DNA arrays using oligonucleotide-modif ied gold nanoparticle probes and a conventional flatbed scanner is describe d here. Labeling oligonucleotide targets with nanoparticle rather than fluo rophore probes substantially alters the melting profiles of the target; fro m an array substrate. This difference permits the discrimination of an olig onucleotide sequence from targets with single nucleotide mismatches with a selectivity that is over three times that observed for fluorophore-labeled targets. In addition, when coupled with a signal amplification method based on nanoparticle-promoted reduction of silver(I), the sensitivity of this s canometric array detection system exceeds that of the analogous fluorophore system by two orders of magnitude.