Electrochemical DNA biosensor based on aldehyde-agarose hydrogel modified glassy carbon electrode for detection of PML/RARa fusion gene

A novel electrochemical biosensor based on a glassy carbon electrode (GCE) modified with aldehyde-agarose hydrogel films was developed for the detection of PML/RARa fusion gene in acute promyelocytic leukemia (APL). To generate the aldehyde groups that will react with probe, the diol groups in the activated agarose gels were transformed into aldehyde groups by reaction with NaIO4. Immobilization is based on the reaction between aldehyde groups in aldehyde-agarose and primary amino groups in the probe. The probe was covalently immobilized on the surface of the GCE. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) was used to detect PML/RARa fusion gene in APL based on methylene blue (MB) as an electrochemical indicator. The electrochemical behavior and the determination of the probe in APL PML/RARa fusion gene using GCE were studied by DPV. The results indicated that in Tris–HCl buffer solution (pH 7.0), the relationship between the oxidation peak current of MB and the concentration of complementary strand was linear in the range of 4.0 × 10−12 to 1.2 × 10−11 M. The detection limit was estimated as 4.0 × 10−12 M. The presented method exhibited excellent specificity for complementary and single-mismatch dsDNA after hybridization and will be applied to the assay of PCR-amplified DNA extracted from real sample showing the potentialities of this approach for routine analysis.