An ultrasensitive electrochemical DNA biosensor based on graphene/Au nanorod/polythionine for human papillomavirus DNA detection

An ultrasensitive electrochemical DNA biosensor for human papillomavirus (HPV) detection was developed by electrochemical impedance spectroscopy and differential pulse voltammetry. A capture probe was immobilized on a glassy carbon electrode modified with graphene/Au nanorod/polythionine (G/Au NR/PT). Two auxiliary probes were designed and used to long-range self-assemble DNA nanostructure. The target DNA can connect DNA structure to the capture probe on the electrode surface. [Ru(phen)(3)](2+) was selected as a redox indicator for amplifying electrochemical signal significantly. Enhanced sensitivity was obtained through combining the excellent electric conductivity of G/Au NR/PT architecture and the long-range self-assembly DNA nanostructure with the multi-signal amplification. The DNA biosensor displayed excellent performance for HPV DNA detection over the range from 1.0 x 10(-13) to 1.0 x 10(-10) mol/L with a detection limit of 4.03 x 10-(14) mol/L Furthermore, the proposed method can also be used for the detection of HPV DNA in human serum samples and provides a potential application of DNA detection in clinic research. (C) 2015 Elsevier B.V. All rights reserved.