Design of gold nanoparticle modified electrodes and their applications for the detection of electrochemical dna hybridization

With the development of nanotechnology there is an increased usage of nanomaterials in the design of electrochemical DNA biosensors based on nucleic asids and thus more sensitive and selective biosensor platforms were developed. In the first part of our study, the experimental conditions to modify disposable pencil graphite electrode surfaces were optimized. The electrode surface was firstly modified with 2-Amino-5-mercapto-1,3,4-thiadiazole (AMT). By this way it was aimed to bind gold nanoparticles (AuNPs) to the electrode surface since AMT contains thiol groups. The microscopic characterization of the electrodes were performed by using scanning electron microscopy (SEM). Probe sequence related to Hepatitis B virus (HBV) was immobilized onto the AuNPs modified electrode surface. In the second part of our study the detection of hybridization studies by using probe immobilized AuNPs modified electrodes was performed. The selectivity of the electrode was tested by using target DNA, one base mismatch (MM) and non comlementary (NC) DNA sequences and detection limit was determined. The electrochemical impedance spectroscopy (EIS) technique was applied for all experiment in our study and the detection of hybridization was investigated according to the changes at the values of the charge transfer resistances (Rct).