ABSTRACT
A new electrochemical method for telomerase activity assay was developed on the basis of hybridization chain reaction ( HCR)-assisted multiple signal amplification, aiming at improving the sensitivity and specificity of telomerase assay. The experiments utilized HeLa cells as original source of the telomerase in the electrochemical studies. The telomerase primer was firstly self-assembled on the surface of gold electrode. The telomerase catalyzed the elongation of the primer, producing the complementary sequences of hairpin probe H1. In this case, HCR was then initiated by interacting with two hairpin probes H1 and H2. Because both H1 and H2 were modified by biotin, horseradish peroxidase could be captured on the electrode surface through the high-affinity interaction between biotin and streptavidin, catalyzing the oxidation of o-phenylenediamine to produce 2,3-diaminophenazine. Therefore, the telomerase assay was realized by tracing the electrochemical signals with differential pulse voltammetry. This electrochemical method was of high efficiency and feasibility for detecting telomerase activity, and could trace the telomerase activity down to 10 cells/mL HeLa cells with a wide linear range. Besides, it could also easily distinguish the target enzyme from the control proteins with high specificity.