Telomere elongation-based DNA-Catalytic amplification strategy for sensitive SERS detection of telomerase activity

Telomerase has been regarded as a biomarker for cancer diagnosis as well as the clinical treatment and the reliable detection of intracellular telomerase activity is of great significance. By developing a telomere elongation-based DNA-catalytic amplification strategy, a novel surface-enhanced Raman scattering (SERS) method is proposed for the assay of telomerase activity. In the presence of telomerase and nucleotide mixture dNTPs, the telomerase substrate (TS) primer extended and generated a long single-strand DNA (ssDNA) containing the telomere repeat units (TTAGGG)n, which could catalyze the entropy-driven circuit reaction (EDCR). One of the products of EDCR was ingeniously used as the catalyst of catalytic hairpin assembly (CHA) occured on magnetic beads (MBs). As a result, a large amount of ROX-labeled Raman probes could be anchored on the surface of MBs and used for SERS detection. Using this strategy, the assay can detect telomerase activity from cell extracts equivalent down to single HeLa cell.