Adsorptive Transfer Stripping for Quick Electrochemical Determination of microRNAs in Total RNA Samples
Electrochemical methods hold promise for fast and inexpensive determination of cancer biomarkers, including microRNAs playing an important role in regulation of gene expression. We developed a simple assay utilizing (i) microRNA labeling with osmium(VI) complexes, (ii) hybridization of microRNA with magnetic bead-immobilized capture probe, and (iii) adsorptive transfer stripping (AdTS) technique in which working electrode is dipped into a microliter-sized drop for direct adsorption of microRNA. Increased sensitivity and decreased sample consumption was achieved, and nanogram quantities of microRNA present in 500-fold excess of total RNA were determined. Our results indicate only negligible interference during hybridization from other RNA molecules.