Paper-based electrochemiluminescence telomerase activity detection using hybridization chain reaction and CRISPR/Cas12a dual signal amplification

Abstract

Sensitive telomerase activity detection becomes particularly significance since the important value of it in early cancer diagnosis as a potential biomarker. Herein, we developed a paper-based analytical devices (PADs) for telomerase activity detection, using positively charged Au@luminol nanoparticles ((+)Au@luminol NPs) as electrochemiluminescence (ECL) signal probe coupling with hybridization chain reaction (HCR) and CRISPR/Cas12a dual signal amplification. Firstly, the initial strong ECL signal was obtained based on the electrostatic adsorption of (+)Au@luminol NPs onto the surface of HCR double-stranded hybrid aggregates. In the presence of telomerase, the primer was efficiently elongated with telomeric repeats of (TTAGGG)_n to release activator DNA and trigger the CRISPR/Cas12a, which can prevent the happen of HCR and the adsorption of (+)Au@luminol NPs through cleaving the capture probe on the electrode surface, such results directly inducing the decrease of the ECL signal that was proportional to telomerase concentration, due to the efficient signal amplification of HCR and CRISPR/Cas12a, a low detection limit of 2.3 cells/mL for telomerase could be detected. Moreover, the sensor realized the effective application for telomerase extracts analysis in human serum samples, making it possess potential application value for telomerase activity assays in cancer diagnostics.