Electrochemical Sensor for Detection of miRs Based on the Differential Effect of Competitive Structures in the p19 Function

Abstract

The present study aim to design a liposomal electrochemical sensor using 1, 2-dioleoyl-3-trimethylammoniumpropane (DOTAP) and dioleoylphosphatidylethanolamine(DOPE), chimeric probes and p19, it has been considered as a caliper molecule as well. Also the competitor structural hybrid (RNA) was used to detect three types of miRs in one screen printed electrode modified by gold nanoparticle (SCPE/GNP). In this purpose, the sensor signal stabilized when the cationic DOTAP-DOPE with hybrids of the chimeric probes (Stem, M-linear) sandwiched in order to detect 221-124a miRs. Given the lack of accessibility to RNA-miRs segments of chimeric probes, p19 inhibited the electrochemical reaction and shifted signal to off. After that p19 connected with the free hybrid of T-linear/21miR (just RNA) as competing for structure and the signal was shifted to ON, again. In this study, the electrochemical measurements were performed between the potentials at-0.4 V and +0.4 V with 1 mM [Fe(CN)6]-3-/4 which DOTAP-DOPE acted as an enhancer layer in the electrostatically reaction. This sensor determines as low as 0.4 fM of miRNA with high selectivity and specificity for sequential analysis of 124a-221-21 miRs in just 2 h.