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 × 10 2 to 1.04 × 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.