A label-free electrochemical DNA sensor to identify breast cancer susceptibility

Detection of mutations related to cancer predisposition has been an important action in the prevention of cancer and in the cancer genetic profiling. Breast cancer (BRCA) genes mutations are widely known for their relation to genetic predisposition to breast and ovarian cancer. However, the access to genetic tests is still limited. Here, a label-free DNA sensor to detect the mutation 185delAG in the breast cancer 1, early onset (BRCA 1) gene, a founder mutation in the Ashkenazi population, is described. Based on the DNA hybridization and electrochemical impedance spectroscopy (EIS), the sensor was able to distinguish between the mutated and non-mutated sequences, a two-base mismatch. Using a single-strand thiol-modified 25-mer DNA sequence (HS-ssDNA) as probe immobilized in a gold electrode, hybridization studies were performed with [Fe(CN)6]4 − as redox probe and resulted in DNA sensor with a low limit of detection of 0.15 nmol L− 1 in a linear range from 1 to 200 nmol L− 1. This DNA sensor shows prominent electrochemical performance and might be an interesting alternative to distinguish between mutated and non-mutated BRCA1 genes.