| DNA electrochemical biosensors have received much attention due to the high sensitivity, specific, rapid response, easy handling, compatibility with miniaturization technology, and low cost. One key to a successful electrochemical biosensor is the sensitivity of the electrode materials. This article prepare acidized MWCNTs using ultrasound assisted microwave extraction method for the first time. Thus DNA electrochemical sensor based acidized MWCNTs was prepared. This sensor was used to determine the concentration of complementary sequences while the detecting process, the effect of intercalation time,intercalation concentration,hybridization solution to the detection result was discussed.After the characterization of acidized MWCNTs using SEM,TEM,HRTEM,SPM,EDS and FTIR methods,it shows that we can abtain functional MWCNTs with high quality and purity through ultrasound assisted microwave extraction for 40 minutes at 40oC using 3:1 mixed acids.This extraction method was simple with fine reproducibility. On the catalytic efficiency study of MWCNTs, the electrochemical behavior and content determination of ACOP using MWCNTs modified electrode were studied by cyclic voltammetry. This modified electrode shows excellent electrocatalysis characteristics for ACOP with high sensibility ,quick response and fine selectivity.The optimized response of indicator can be got while hybridization solution is PBS( pH7.0),DNR concentration is 10μM, and hybridization condition is 40 minutes when 45oC.While detecting the complementary DNA standard concentration, the lower limit is 8.0×10-10mol/L.In the range of 4.0×10-9～1.0×10-7 mol/L,there was a simple equation between the respond signal of indicator and the concentration of complementary DNA.It shows MWNTs can significantly elevate the amount of DNA immobilization and the rate of electron transfer between electrode and intercalating agent.As a result,the fundamental characteristic such as stability,specificity was better than that of the bare GCE.
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