Simultaneous detection of telomerase and miRNA with graphene oxide-based fluorescent aptasensor in living cells and tissue samples.

Telomerase and microRNAs (miRNAs) as important biomarkers are closely related to cancers. Simultaneous detection of telomerase activity and miRNAs would be beneficial to improve the specificity and reliability. Here, we establish a telomerase and miRNA-21 (miR-21) simultaneous sensing platform with graphene oxide-based fluorescent aptasensors (GOFA) including graphene oxide (GO), template strand (TS) primer and fluorophore-labeled telomerase/miR-21 oligonucleotides. Owing to π-π stacking interaction, TS primer and telomerase/miR-21 probes would be loaded onto GO, resulting in fluorescence quenching. However, in the presence of the telomerase or miR-21, the double-stranded oligonucleotides would be away from the GO surface attribute to the hybridization between the extended TS primers and telomerase probe as well as miR-21 and miR-21 probe, leading to obvious fluorescence recovery. We found that GOFA could simultaneously detect telomerase activity and miR-21 with low background signal, high sensitivity and simplified operation. Moreover, GOFA could be used for accurately detecting telomerase activity and miRNA in living cells and cancer patient tissue sample. This sensing platform shows great potential in improving the accuracy in clinical diagnosis of cancer.