Nanoscaled Porphyrinic Metal–Organic Frameworks for Electrochemical Detection of Telomerase Activity via Telomerase Triggered Conformation Switch

In this work, we designed a nanoscaled porphyrinic metal–organic framework (PorMOF) with iron porphyrin as linker and zirconium ion as node for electrochemical detection of telomerase activity. The as-prepared PorMOF was characterized with scanning electron microscopy, powder X-ray diffraction, and spectroscopic techniques and demonstrated excellent electrocatalytic activity toward O 2 reduction. Sequentially, the functionalization of PorMOF with streptavidin results in a water-stable electrochemical tracer for detection of telomerase. Upon the telomerase-triggered extension, the assistant DNA 1 (aDNA1)–assistant DNA 2 (aDNA2) duplex could switch into a hairpin structure, and thus, the aDNA2 was released and then hybridized with the capture DNA. Therefore, the PorMOF@SA tracer could be introduced on the electrode surface via biotin–streptavidin recognition, leading to the strong electrochemical signal for readout. The developed approach displayed desirable dynamic range and limitation of detection down to 30 HeLa cells mL –1 . The telomerase activity was 2.2 × 10 –11 IU in a single HeLa cell with good reproducibility and stability. The nanoscaled porphyrinic MOF provided a powerful platform for electrochemical signal transduction and had a promising application in the determination of various biomolecules.