Abstract
A simple and label-free electrochemical DNA hybridization sensor was developed based on a poly(thionine)/gold nanoparticle composite-modified indium tin oxide (PTH/GNPs/ITO) electrode. The PTH/GNPs/ITO electrode was prepared by the electrode-position of GNPs on ITO followed by the electropolymerization of thionine (TH). Probe DNA (pDNA) was immobilized on this substrate via covalent linkage between the -NH2 group of PTH and the PO4 3− group at the 5 end of pDNA. The immobilized single-strand pDNA increased the stiffness of the PTH film and decreased the PTH oxidation current, whereas the current was reduced to a greater extent after the formation of double-strand DNA by the hybridization of target complementary DNA (cDNA). The pDNA/PTH/GNPs/ITO sensor exhibited excellent stability, and selectivity to discriminate DNA base pair mismatches. The semi-log plot of the [cDNA] vs. oxidation current of PTH was linear in the concentration range of 1 μM−1 fM with the detection limit (S/N=3) and sensitivity of ca. 0.3 fM and ca. 2.0 μA·cm−2fM−1, respectively.
Original language | English |
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Pages (from-to) | B153-B157 |
Journal | Journal of the Electrochemical Society |
Volume | 163 |
Issue number | 5 |
DOIs | |
State | Published - 2016 |