Label-free electrochemical DNA biosensor based on a glassy carbon electrode modified with gold nanoparticles, polythionine, and graphene

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

“…G/Au NR/PT modified GCE provided an excellent platform for further immobilization. CP was immobilized on G/Au NR/PT GCE both through strong Au-S bond Zhang and Huang, 2012), and the electrostatic interaction with the positively charge Au NRs (Lu et al, 2013). The presence of MCH aimed to block the nonspecific binding sites.…”

“…Thionine was then electropolymerized on the G/Au NR GCE followed the reported method (Zhang and Huang, 2012). The deposition experiment was carried out from an acetate buffer solution (0.1 mol/L, pH ¼6.0) containing 0.5 mmol/L thionine using cyclic voltammetry (CV).…”

Label-free electrochemical DNA biosensor for rapid detection of mutidrug resistance gene based on Au nanoparticles/toluidine blue–graphene oxide nanocomposites

“…This is in accordance with the literature [40], revealing that the TB attached on GO surface retained the redox properties. Absorption of Au NPs increased the conductivity of the TB-GO film, resulting in the increase of the redox peak current as the Au NPs acted as a conducting wire or an electron communication relay, which increased the electron transfer efficiency (curve c) [27,41]. When probe DNA was immobilized on the surface of the electrode, the redox peak current of TB decreased.…”

“…When probe DNA was immobilized on the surface of the electrode, the redox peak current of TB decreased. After hybridization with target DNA, the peak current of the modified electrode further decreased, indicating that dsDNA formed an electron-transfer and mass-transfer blocking layer, which greatly inhibited the reaction on the electrode surface [27,42]. The CVs of the DNA biosensor in 0.1 M PBS (pH 7.0) at different scan rates were also studied.…”

“…On the other hand, Au nanoparticles (Au NPs) have also drawn much attention in electrochemical field because of its excellent characteristics, such as large surface area, high chemical stability, good biocompatibility, and being able to facilitate electron transfer between biomolecules and electrodes [24,25]. Moreover, Au NPs can link with a lot of compound through Au NH or Au S chemical bond or electrostatic interaction because of its negatively charge [26][27][28]. For these reasons, Au NPs have been widely used for fabrication of biosensors.…”