Electrochemical DNA biosensors for label-free breast cancer gene marker detection.

We present an electrochemical DNA detection strategy based on self-assembled ferrocene-cored poly(amidoamine) dendrimers for the detection of a gene relevant to breast cancer. The chemisorption of three ferrocene-cored poly(amidoamine) generations and hybridization of single-stranded DNA on a Au electrode were studied by cyclic voltammetry and differential pulse voltammetry. The biosensor demonstrated high sensitivity of 0.13 μA/(ng/ml) in the detection of the target DNA with a linear range of 1.3-20 nM and a detection limit of 0.38 nM. The DNA biosensor also has high selectivity for the target DNA, showing a clear signal difference from a noncomplementary sequence and a single-base-mismatch sequence, which was used as a model of BRAC1 gene mutation. The results shown are highly motivating for exploring DNA biosensing technology in the diagnosis of breast cancer caused by mutation of the BRAC1 gene. Graphical abstract.