An Enzyme-Free and PCR-Free Biosensing Platform for Accurate Monitoring of Telomerase Activity

Abstract

We describe a PCR-free, enzyme-free, and simple biosensing platform for the electrochemical monitoring of telomerase activity based on Au nanorods (AuNRs) as an electrocatalytic redox mediator, which enhances the electrochemical signal by catalyzing acetaminophen (AP). In this process, acid-functionalized ordered mesoporous carbon (OMC) was modified on a glassy carbon electrode (GCE) surface to offer -COOH sites. Moreover, the amino-modified S1 was fixed on the modified electrode by conducting an amide reaction. TS is extended to (TTAGGG)n repeat units in the presence of telomerase extract and dNTPs. One end (5') is hybridized with S1 on the electrode, and the other end (3') is combined with AuNRs-S2 probe. Obviously, the telomerase activity is relevant to the amount of connected AuNRs, resulting in different response signals. Therefore, with the telomerase extension triggered hybridization reaction, a large amount of AuNR catalyst was introduced onto the surface of GCE as the sensing platform, thus achieving a sensitive electrochemical telomerase activity assay in the range of 20–2.15×106 HeLa cells mL-1. This sensing platform shows that the limit of detection is 1.74 HeLa cells mL-1, thus providing a promising method for the determination of telomerase activity and a powerful biosensor for accurate cancer monitoring and diagnosis.

Keywords: Telomerase activity, Electrochemical biosensor, Enzyme-free, PCR-free