An approach toward SNP detection by modulating the fluorescence of DNA-templated silver nanoclusters

Abstract

A rapid,homogeneous,andin-situlabelableformatdesignedtodetectsinglenucleotidepolymorphism (SNP) ispresented.Fluorescentsilvernanoclustersproducedfollowinghydride-mediatedreductionof Agþ boundtoapartialdouble-strandedoligodeoxynucleotidewereemployedasprobesforSNPs.The sensingmechanismisbasedonthefluorescenceenhancementofsilvernanoclustersthroughan irreversibleclustertransferuponhybridization.Thekeyelementofourdesignismodulatingthe‘‘turn on’’ mechanismbyintroducingacompetitorthatcanbedisplacedinresponsetoatargetDNA.Ina controlledmodelsystem,thefluorescenceintensityofsilvernanoclustersisapproximately3-fold enhanceduponhybridizationwithaperfectlymatchedtargetDNA,andsingle-basemismatch detectionisachievedwithin5min,regardlessofthepositionofmismatches.Humanaldehyde dehydrogenase2(ALDH2),whichisresponsiblefortheoxidationofaldehydestocarboxylicacids,is then utilizedasatargetforSNP.Uponadditionofaperfectlymatchedsequence,dramaticallyenhanced fluorescenceintensityisobserved(ca.48-fold),andpromptSNPgenotypingisaccomplished.