Spectrophotometric and Electrochemical Determination of MicroRNA-155 Using Sandwich Hybridization Magnetic Beads

ABSTRACT

Here a new colorimetric assay and electrochemical biosensor for microRNA detection based on magnetic bead separation and enzyme amplification are reported. MicroRNA-155 was selected as a model because of its involvement in breast and lung cancer. A novel platform was developed for label-free microRNA detection based on a sandwich assembly using streptavidin magnetic beads coupled with a biotinylated capture probe that hybridized only a portion of the microRNA, the remainder hybridized with biotinylated detection probe linked to streptavidin-alkaline phosphatase. After appropriate reaction with the substrate, the enzymatic product was evaluated with colorimetric and electrochemical detection. The electrochemical method showed high sensitivity, allowing microRNA detection at 29 pmol L⁻¹, which correspond to 1.4 fmole in 50 μL with a linear range from 81 pmol L⁻¹ to 1.2 nmol L⁻¹. This simple and efficient biosensor may have application in clinical molecular diagnostics and biomedical research.

KEYWORDS:

• Differential pulse voltammetry
• microRNA-155 sensor
• sandwich magnetic bead hybridization
• screen-printed carbon electrodes
• spectrophotometry

Additional information

Funding

The authors are grateful to the Fondation Lalla Salma-Prévention et Traitement du Cancer for financially supporting this work in the framework of the Project AP2013. The authors are grateful also to the Islamic Educational, Scientific, and Cultural Organization for financially supporting this work in the framework of the Project No 3.8.2.1.1/3A: ICPSR/2015.