Telomerase Triggered Strand Displacement Cycles at DNA Tetrahedron Layer for Highly Sensitive Electrochemical Biosensing

Accurate analysis of human telomerase is of great significance for the early diagnosis and therapy of cancers. In this study, we have designed a novel toehold-mediated strand displacement amplification strategy for the electrochemical detection of telomerase. A one-pot reaction is involved at the top of tetrahedral DNA nanostructures, which were previously immobilized at the electrode interface. Telomerase extended product first initiates strand displacement cycles, which further lead to the localization of electrochemical species. The level of target telomerase can thus be determined by measurement of the electrochemical response with high sensitivity. Furthermore, this approach is applicable for the screening of inhibitors and successfully distinguishes relative telomerase activities among different cells. It circumvents the drawbacks of traditional telomerase assays and exhibits appealing features like convenient operation, high sensitivity, and selectivity. It is demonstrated to be a promising tool for applications in telomerase-associated early diagnosis and antitumor drug screening.