A gold-nanoparticle-based fluorescence resonance energy transfer probe for multiplexed hybridization detection: accurate identification of bio-agents DNA

We report a gold-nanoparticle-based miniaturized, inexpensive and battery- operated ultra-sensitive fluorescence resonance energy transfer ( FRET) probe for screening biological agents DNA at the femtomolar level. We demonstrate a hybridization detection method using multicolor oligonucleotide- functionalized organic dyes and gold nanoparticles as nanoprobes. In the presence of various target sequences, detection of sequence- specific DNA is possible via an independent hybridization process. As proof of concept, multiplexed detection of two target sequences, ( 1) oligonucleotide sequence associated with the anthrax lethal factor and ( 2) sequence related to positions 1027 - 1057 of the E. coli 23S rDNA, have been demonstrated with high sensitivity and specificity. The quenching efficiency as a function of distance is investigated. The mechanism of distant dependence fluorescence quenching has been discussed.