A new approach to amplified telomerase detection with polyvalent oligonucleotide nanoparticle conjugates

We report a new assay for human telomerase activity that relies on polyvalent oligonucleotide nanoparticle conjugates as diagnostic probes and amplification units. Gold nanoparticles functionalized with specific oligonucleotide sequences can efficiently capture telomerase enzymes and subsequently be elongated. Both the elongated and unmodified oligonucleotide sequences are simultaneously measured. The two strands not only serve as internal positive controls for each other but also provide a way of amplifying signal. At high concentrations, both elongated and unmodified strands exhibit measurable responses. At low telomerase concentrations (e.g., from 10 HeLa cells), elongated strands cannot be detected, but the unmodified sequences, which come from the same probe particles, can be detected because their concentration is higher, providing a novel form of amplification. This new assay rivals the sensitivity of the conventional PCR-based method of telomerase detection.