Electrochemical Studies Of Gene CK-19

DNA electrochemical biosensor is a novel biosensor which is a hot research over the world in recent years. As it has advantages of simple equipment, fast analysis, high sensitivity, DNA electrochemical is deem as the most expectative analysis.CK-19 is a low molecular weight keratin which consists of the epithelial cells skeleton. It mainly express in the epithelium and epithelial tumors as the specific maker of the epithelial tissue. As CK-19 also highly express in breast cancer instead of normal peripheral blood, bone marrow and lymph nodes, so it can be used as tumor markers for breast cancer detection.In this article, CK-19 gene firstly used as specific probes immobilized on the gold electrode surface by self-assembly method. For exploring the immobilization condition of the probe, the electrochemical impedance spectroscopy and electrochemical active indicator MB are applied. The experimental results showed that the lagest amount of the gene fragment immobilized electrode is 3.0 umol/L and the best immobilization temperature and time are 4℃,20h.In addition, a novel hybridization indicator, Hoechst 33258 used to construct electrochemical DNA biosensor. The results show that , Hoechst 33258 is a strong specific indicator that can distinguish the complementary and non-complementary sequence of gene CK-19. It improved good detection that CK-19 probe modified electrodes hybrid for 30min at 55℃in PH 7.0 phosphate buffer solution (PBS). On the range of 5.0×10-7~ 5.0×10-6 M, there was good linear relationship between the respond signal and the concentration of complementary DNA, the lowest limit is 0.018M. It provided a good basis of detection research in practical samples.