Stripping potentiometric transduction of DNA hybridization processes

DNA hybridization on carbon paste electrodes was followed by stripping potentiometric measurement of electroactive metal complexes associated with surface hybrids. The chronopotentiometric transduction mode offers high sensitivity and effective background compensation, and improves the sequence detection compared to analogous (cyclic- and square-wave) voltammetric measurements. Immobilization of the single-stranded nucleic-acid probe is accomplished by adsorptive accumulation onto an anodically activated carbon paste transducer. Variables of the probe immobilization, hybridization and intercalation steps, and chronopotentiometric transduction have been examined and optimized. The resulting assay protocol offers convenient quantitation of nanogram quantities of the target strand in connection with short (5–20 min) hybridization times.