A novel and sensitive electrochemical DNA biosensor based on Fe@Au nanoparticles decorated graphene oxide

A novel and sensitive electrochemical biosensor for selective determination of DNA was developed based on Fe@Au nanoparticles (Fe@AuNPs) involving 2-aminoethanethiol (AET) functionalized graphene oxide (GO) (Fe@AuNPs-AETGO). Firstly, 5′-TA CCG GGT GCT CGA GCT-(CH2)3-SH-3′ single-stranded probe (ss-DNA) was immobilized on Fe@AuNPs-AETGO nanocomposite to form ssDNA-Fe@AuNPs-AETGO. Square wave voltammetry (SWV) was applied to monitor the DNA hybridization by basic blue 41 (BB41) as an electrochemical indicator. The DNA immobilization and hybridization on the film were studied by cyclic voltammetry (CV), SWV and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the peak currents of BB41 were linear with the logarithm of the concentrations of complementary DNA (5′-AT GGC CCA CGA GCT CGA-(CH2)3-SH-3) from 1.0 × 10−14 to 1.0 × 10−8 M with a detection limit of 2.0 × 10−15 M. The biosensor also showed high selectivity to one-base, two-base and three-base mismatched DNA. Compared with the other electrochemical DNA biosensors, the proposed biosensor showed its own performance of simplicity, good stability and high sensitivity.

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