Double determination of long noncoding RNAs from lung cancer via multi-amplified electrochemical genosensor at sub-femtomole level

An ultrasensitive electrochemical genosensor has been fabricated for the double determination of two different specific sequences deduced from the maternally expressed gene3 (MEG3) lncRNA (long noncoding RNA), which was demonstrated by coupling RNase A-aided target recycling with DNA supersandwich-induced signal enhancement, based on a composite interface of graphene-like tungsten disulfide/dendritic gold nanostructures (WS2/DGN). Firstly, duple target sequences of T1 and T2 were captured by the primer probes of P1/P2 functionalized Fe3O4@C magnetic nanoparticles, via the DNA/RNA hybridization between T1/T2 and P1/P2. In the presence of RNase A, T1 and T2 were released to trigger the target recycling, accompanied by the generation of numerous intermediate DNAs designated as IT1 and IT2, respectively. After the magnetic separation, the IT1 and IT2 were liberated and hybridized with the capture probes of CP1/CP2 loaded DGN/WS2 modified electrode. Subsequently, the stepwise DNA hybridization chain reactions (HCR) labeled with ferrocene (Fc) and methyleneblue (MB) were processed, respectively. The DPV current values of Fc and MB were recorded, which were proportional with the concentration of T1 and T2, respectively. Using the multiplexed amplification strategy, this newly designed genosensor provided a wide linear range from 1 fM to 100 pM with a low detection limit of 0.25 fM for T1 and 0.3 fM for T2. The application of the genosensor in real serum sample has also been studied, confirming the excellent selectivity and sensitivity for the application in bioanalysis and clinical diagnostics.