Sequential or multiplex electrochemical detection of miRs based on the p19 function relative to three sandwiches of different structural hybrids on the liposomal sensor

In this work, we designed a liposomal electrochemical sensor with DOTAP-DOPE liposome, chimeric probes, p19 as a caliper molecule, and the competitor structural hybrid (just RNA) for detection of three micro-RNAs in one SPCE/GNP electrode. The sensor is stabled when the cationic spherical DOTAP-DOPE liposomes sandwich with hybrids of the different sandwiched of probes (T-M-linear, Stem) and 21-124a-221miRs. With the addition of P19, in the presence of a sandwiched competitor (T-linear/21miR), the system is stable (ON) and is shut off in the presence of structural sandwiched hydrides of M-linear + 124a/Stem + 221 miR due to the lack of adequate access to segments of RNA-miRs of chimeric probes. For the first time in this study, three probes were sandwiched on the separate liposome for sequential identification of 21-124a-221 or multiplex detection of miRs (221 or 124a with 21) with high specificity and sensitivity (as low as 0.1 fM). Electrochemical impedance (EIS) were performed for sensing three miRs in PBS containing 1 mM [Fe(CN)6](-3/-4) which DOTAP-DOPE liposome acted as an enhancing intermediate layer in the electrochemical reactions. Transmission Electron Microscopy (TEM)), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS) and Ultraviolet-Visible (UV) spectroscopic techniques are used to understand the interactions between the DOPE-DOTAP, AuNP, different probes, miRs and p19.