Label-free and amplification-free miR-124 detection in human cells.

MicroRNAs (miRNAs) are becoming a very important group of molecules especially since their connection to numerous diseases has been revealed. The potential in gene therapy as well as in diagnostics is being widely investigated leading to the demand of sensitive, selective and simple methods of isolation and detection. The combined advantages of magnetic particle-based separation with sensitive electrochemical detection may offer a very valuable tool for these purposes. In this study, the miR­124 was targeted as an example analyte for development and optimization of the isolation procedure coupled to the electrochemical detection. The sensitivity of the method was demonstrated by the limit of detection at the level of nanomolar concentration (4 nM). To verify the applicability of the procedure to the real samples, miR­124 was isolated from the human embryonic kidney cells naturally expressing this miRNA molecule and the results were compared to the amount of miR­124 isolated from the cells transfected by the pENTR-miR­124 plasmid leading to the overexpression of miR­124.