Label-free Fluorescence Assay of Telomerase RNA Based on Strand Displacement Amplification

A novel fluorescence method was developed for detecting telomerase RNA( hTR) based on the fluorescence resonance energy transfer( FRET) and strand displacement amplification( SDA) technique. Graphene oxide( GO) served as DNA carrier and fluorescence quencher. SYBR Green I ( SG I) and hairpin DNAs ( hpDNA) are fluorescence probe and molecular recognition probes, respectively. The fluorescence of SG I that intercalated into the stem of hairpin DNAs was quenched when hpDNA1 and hpDNA2 were adsorbed onto the surface of GO. In the presence of T1, the hybridization reaction between hpDNA1 and T1 opened the hairpin structure of hpDNA1 to trigger the SDA reaction between hpDNA2 and T1, leading to an accumulation of hpDNA1/hpDNA2 hybrids. The rigid dsDNA desorbed from GO surface to restore the fluorescence of SG I. Based on the change in fluorescence intensity, T1 can be quantitatively detected from 0. 2 nmol/L to 50 nmol/L, with a detection limit of 90 pmol/L. Therefore, it offers a label-free, highly sensitive and specific fluorescence strategy for detection of hTR.