基于核酸外切酶Ⅰ催化的核酸降解反应构建乳腺癌细胞电化学传感器

An Electrochemical Biosensor for Detection of Breast Cancer Cells Based on Exonuclease Ⅰ-catalyzed DNA Degradation Reaction

基于核酸外切酶I选择性消化单链核酸的特点,使用MCF-7细胞表面过量表达的肿瘤标志蛋白MUC1的适体,构建了一种灵敏检测乳腺癌细胞的新型电化学传感器。核酸适体链与乳腺癌细胞MCF-7表面过量表达的肿瘤标志蛋白MUC1的结合会阻碍其与互补核酸探针链的杂交,所以电极表面固定的未杂交的核酸探针单链就会被外切酶I选择性消化从而失去末端的亚甲基蓝信号分子。因此,通过检测电化学信号的变化,此传感器在103~106 cell/mL细胞浓度范围内线性检测乳腺癌细胞MCF-7,检出限为330 cell/mL,具有高度特异性,可以有效区分对照细胞胰岛β细胞。

In terms of the characteristic of exonuclease I that can selectively catalyze the degradation of single-stranded DNA, we report a new sensitive electrochemical biosensor for the detection of breast cancer cells by using the aptamers of MUC1 that is overexpressed on the surface of MCF-7 cells. Because the binding of aptamer and MUC1 that is over-expressed on the surface of breast cancer cell MCF-7 can prevent its hybridization with the complementary probe DNA, the unhybridized single-stranded probe DNA that is immobilized on the electrode surface will be selectively digested by Exonuclease I and result in the removal of the signal molecule methylene blue. Therefore, by tracing the changes in electrochemical responses, the biosensor can be used to sensitively detect MCF-7 cells in a linear range from 103 to 106 cell/mL with a detection limit of 330 cell/mL, and easily distinguish the control islet β cells with high specificity.