A sensitive electrochemical genosensor for highly specific detection of thalassemia gene

Beta thalassemias (βth) are the result of mutations in the β-globin gene. In this report, an electrochemical genosensor was made to detect the sequences anent with the β-globin gene. This biosensor is based on immobilizing 20-mer single stranded oligonucleotide (probe) on the Au nanoparticles- poly (4-aminothiophenol)/ reduced graphene oxide/glassy carbon electrode (AuNPs-PAT/rGO/ GCE) and hybridizing this oligonucleotide along with its complementary sequence (target). The vastness of the probe and target sequences hybridization was studied through differential pulse voltammetry (DPV) along with electrochemical impedance spectroscopy (EIS) using the [Fe(CN)6]^3-/^4- (1:1) as a hybridization index. The biosensor indicated great efficiency with significant sensitivity along with favorable selectivity. The DPV and EIS responses with the intended concentrations of the sequence were linear varying from 1.0 pM to 400.0 pM (I_p ν log C) and 0.5-400.0 pM (∆R_ct ν log C) with a limit of detection of 0.06 pM and 0.035 pM, at the signal to noise ratio of 3σ. The biosensor of the DNA indicated proper discrimination capability to mismatched two-base, three-base, and non-complementary sequences.