The Electrochemical Capacitive Laber-Free Detection of DNA Modification and Hybridization Process Using Interdigitated Gold Microelectrodes

Detection of specific DNA sequences in biological samples has been playing a fundamental role in genetic diagnostic for rapid identification of diseases. Traditionally DNA hybridization detection is performed by using a redox or fluorescent probe that can detect the hybridization process. These techniques are expensive and time consuming. Considerable effort has been made for more than a decade to miniaturize and integrate the whole process in a single disposable chip. Here, we propose a non-faradaic, label-free, electrochemical method based on capacitance measurement to sense DNA surface modification and hybridization.

For this, we created custom-made Interdigitated-Array gold Microelectrodes using photolithography technique. Silver electroplating was used to make a stable silver chloride quasi-reference. Self Assembled Monolayers of single stranded B. Anthracis hairpin were made and exposed to complementary, non-complementary and 3 bases mismatch to study the hybridization and/or non-hybridization processes using Electrochemical Impedance Spectroscopy measurements.