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DNA electrochemical biosensor is an international hotspot in recent years, the study of a new class of biological sensors, it has a simple instrument , rapid analysis , high sensitivity and is considered a class of people to send in the maximum desired DNA analysis method . CK-19 is a low molecular weight of keratin, are part of the epithelial cells of the skeleton . CK-19 as a specific marker of epithelial tissue , primarily expressed in the epithelial tissue and tumors of epithelial origin , and have a higher expression in breast , but not expressed in normal peripheral blood , bone marrow, tissue, lymph nodes , so can be used as markers for breast cancer for early detection of breast cancer . In this paper, a method of self-assembly , the first time the CK-19 gene fragment as a specific probe fixed to the surface of the gold electrode by AC impedance method and groping probe fixed combination of electrochemical activity indicator MB . Experimental results show that the gene fragment in the electrode surface , the maximum solids loading of 3.0 umol / L, and the optimal fixed temperature , the fixed time respectively 4 ° C and 20H . In addition, the article also constructed as hybridization indicator Hoechst 33258 DNA electrochemical biosensors . Experimental results show that , Hoechst 33258 is a specific indicator, can be effectively stars CK-19 gene in the complementary and non-complementary sequence . CK-19 probe electrode in pH 7.0 phosphate buffered saline (PBS) , 55 ° C hybridization 30min , the detection results . Complementary DNA in 5.0 × 10-7 ~ 5.0 × 10-6 M concentration range , with a detection signal into a linear relationship , the detection limit of 0.018M, provides a good foundation for real samples .
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