Published online by Cambridge University Press: 13 February 2015
The protein survivin (Sur) has been considered as a potential cancer biomarker due to its involvement in disrupting normal cell cycle by stimulating proliferation and inhibiting cell apoptosis. In this work, we have focused on exploring novel platforms for sensitive monitoring of Sur expression, based on molecular beacons and protein modulation of plasmon-controlled fluorescence. In this framework, we show that Sur can be employed in gating the resonance energy transfer (gRET) between fluorescein isothiocyanate probe dye (FITC) and plasmonic citrate-capped gold nanoparticles (AuNP@Cit). Furthermore, we have designed fluorescent dye-bearing molecular beacons (MBs) targeting nucleotides of the survivin mRNA. The antisense oligonucleotide complementary to the target sequence, inserted in the loop area of the hairpin MB structure, has enabled the fluorescence turn-ON MB switching in the presence of the target, thus signaling the high Sur mRNA levels and enhanced Sur protein expression.