Disposable DNA electrochemical sensor for hybridization detection

A disposable electrochemical sensor for the detection of short DNA sequence s is described. Synthetic single-stranded oligonucleotides have been immobi lized onto graphite screen printed electrodes with two procedures, the firs t involving the binding of avidin-biotinylated oligonucleotide and the seco nd adsorption at a controlled potential. The probes were hybridized with di fferent concentrations of complementary sequences. The formed hybrids on th e electrode surface were evaluated by differential pulse voltammetry and ch ronopotentiometric stripping analysis using daunomycin hydrochloride as ind icator of hybridization reaction. The probe immobilization step, the hybrid ization event and the indicator detection, have been optimized. The DNA sen sor obtained by adsorption at a controlled potential was able to detect 1 m u g/ml of target sequence in the buffer solution using chronopotentiometric stripping analysis. (C) 1999 Elsevier Science S.A. All rights reserved.