Sequence determination of DNA pieces using a TPD modified electrochemical biosensor

A new modifier N - [6 - (thien - 3 - yl)acetoxy] - pyrrolidine - 2,5 - dione(TPD) and a sensitive electroactive indicator di[1 - (ferrocene - carbamoylpropyl) - tetrahydropyrazine - 4 - (propyl carbamoyl - pyridine) -] phenazine (FCZ) have been synthesized. TPD is adsorbed on gold surface to immobilize ssDNA as probe. FCZ is intercalated in dsDNA and detected by differential pulse voltammetry. The biosensor is based on a chemically modified electrode, on which TPD - ssDNA is self - assembled. It is sensitive to cDNA with the detection limit being 8 x 10(-10) mol/L. The current signal of the biosensor is proportional to the concentration of cDNA in the range of 2 x 10(-8) to 1 x 10(-7) mol/L. This electrochemical biosensor has been used to detect sequence - specific DNAs related to HIV - 1 and HBV virus.