Microfabricated Disposable DNA Sensors Based on Enzymatic Amplification Electrochemical Detection

A new electrochemical biosensing method was developed based on the immobilization of DNA probes on photolithographic gold film electrodes by self-assembled monolayer technique. The complementary sequence was hybridized to the modified electrode and the hybridization reaction was carried out at 37 degreesC for 1 h. Avidin-akaline phosphatase was coupled to the hybrid through avidin-biotin complex and hydrolyzed to produce an electroactive alpha -naphthol, which could be detected by different pulse voltammetry (DPV). Numerous factors including the concentration of the substrate and incubation time are optimized to maximize the sensitivity and speed in the assay time. The 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.