Novel Label-free Assay of Telomerase Based on DNAzyme

A novel method for telomerase detection based on DNAzyme and toehold-mediated strand displacement was developed. Optimal designing of a hairpin probe ensured efficient inhibition of DNAzyme activity by preventing it from forming the G-quadruplex structure. After the substrate TS was elongated by telomerase, the original hairpin structure could be destroyed through toehold-mediated strand displacement, so that the free DNAzyme. was released, which catalyzed the oxidation of ABTS(2-) to generate an absorbance increase at 415 nm. The results indicated that the proposed method could detect the telomerase as low as 500 Hela cells equivalent. Besides, this method is simple and requires no fluorescence labeling or complicated surface modification, and thus is expected to have a wide use in routine telomerase analysis of tumor cells.