Screen-Printed Electrochemical Biosensor for Detection of DNA Hybridization

A method for detection of DNA hybridization process on the screen-printed electrochemical biosensor was investigated. The screen-printed electrochemical DNA biosensor was immobilized with single-stranded DNA (ssDNA), then adsorbed with electroactive indicator Co(phen)33+. Inductively coupled plasma-Atomic emission spectrometry (ICP-AES) and 1H nuclear magnetic resonance (NMR) were employed to characterize the electrochemical indicator complex which was prepared by the method of complexation reaction. Then cyclic voltammetry (CV) was used to investigate its electrochemical characteristics on the surface of electrodes. On this basis, the process of ssDNA fixed and DNA hybridization event on the electrodes were also studied. Three immobilization methods, direct absorption, covalent binding and electrostatic adsorption, were also discussed. The results indicated that ssDNA was immobilized well by the methods of covalent binding and static adsorption. Meanwhile, the peak current of CV was rising as target DNA hybridized with the probe, which indicated a higher affinity of dsDNA to Co(phen)33+ when the probe was immobilized with electrostatic adsorption. Besides, it displayed peak current is strongly related with target DNA concentration in range of 6.65 × 10-8-4.26 × 10-6 M, R2 = 0.9819. On the basis of the above-mentioned mechanism, the calibration experiment was constructed, and was expected to be used in the detection of disease and pathogenic microorganisms.