Microfabricated disposable DNA sensors based on enzymatic amplification electrochemical detection

A new electrochemical biosensing method was developed based on the immobili zation of DNA probes on photolithographic gold film electrodes by self-asse mbled monolayer technique. The complementary sequence was hybridized to the modified electrode and the hybridization reaction was carried out at 37 de greesC for 1 h. Avidin-akaline phosphatase was coupled to the hybrid throug h avidin-biotin complex and hydrolyzed to produce an electroactive alpha -n aphthol, which could be detected by different pulse voltammetry (DPV). Nume rous factors including the concentration of the substrate and incubation ti me are optimized to maximize the sensitivity and speed in the assay time. T he sensors were employed to detect PCR products relative to the hepatitis B plasmid. The method has a linear calibration range of 1.5 nmol/L-50 nmol/L and the detection limit is 30 fmol.