A label-free electrochemical biosensor for ultra-sensitively detecting telomerase activity based on the enhanced catalytic currents of acetaminophen catalyzed by Au nanorods

An electrochemical biosensor was designed for the determination of telomerase activity using an enzyme-free, PCR-free, and convenient electrochemical strategy. In this work, the electrochemical biosensor was constructed through the functionalization of Au nanorods with a carboxylic group (AuNRs-3) and subsequent immobilization with capture DNA (cDNA) for sensing telomerase activity. Upon telomerase triggered extension, the telomerase activity is related to the amount of the adsorbed electrocatalyst, leading to the different electrochemical signals for readout. Integrating with the efficient electrocatalysis of AuNRs-3-cDNA towards oxidation of acetaminophen, the prepared biosensor exhibits a wide dynamic correlation of telomerase activity from 1 x 10(2) to 1.04 x 10(7) HeLa cells mL(-1) with a sensitivity of 2.68 HeLa cell mL(-1) and the limit of detection was calculated to be 52.81 HeLa cells mL(-1) under the optimal experimental conditions. Furthermore, the application of this electrochemical biosensor would provide the great potential for analysis of telomerase activity, revealing a powerful platform for early diagnosis of cancers.