State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
School of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning 530008, China.
Biosensors (Basel). 2021 Oct 8;11(10):378. doi: 10.3390/bios11100378.
Arch-cruciform DNA are self-assembled on AuNPs/VS scaffold as a highly sensitive and selective electrochemical biosensor for michigan cancer foundation-7 (MCF-7) breast cancer cells. In the construction, arch DNA is formed using two single-strand DNA sequences embedded with the aptamer for MCF-7 cells. In the absence of MCF-7 cells, a cruciform DNA labeled with three terminal biotin is bound to the top of arch DNA, which further combines with streptavidin-labeled horseradish peroxidase (HRP) to catalyze the hydroquinone-HO reaction on the electrode surface. The presence of MCF-7 cells can release the cruciform DNA and reduce the amount of immobilized HRP, thus effectively inhibiting enzyme-mediated electrocatalysis. The electrochemical response of the sensor is negatively correlated with the concentration of MCF-7 cells, with a linear range of 10~1 × 10 cells/mL, and a limit of detection as low as 5 cells/mL (S/N = 3). Through two-dimensional materials and enzyme-based dual signal amplification, this biosensor may pave new ways for the highly sensitive detection of tumor cells in real samples.
十字形 DNA 自组装在 AuNPs/VS 支架上，作为一种用于密歇根癌症基金会-7（MCF-7）乳腺癌细胞的高灵敏度和选择性电化学生物传感器。在构建过程中，十字形 DNA 是使用嵌入 MCF-7 细胞适体的两条单链 DNA 序列形成的。在没有 MCF-7 细胞的情况下，带有三个末端生物素标记的十字形 DNA 与 arch DNA 的顶部结合，进一步与链霉亲和素标记的辣根过氧化物酶（HRP）结合，在电极表面上催化对苯二酚-HO 反应。MCF-7 细胞的存在可以释放出十字形 DNA，并减少固定化 HRP 的量，从而有效抑制酶介导的电催化。传感器的电化学响应与 MCF-7 细胞的浓度呈负相关，线性范围为 10~1 × 10 个细胞/mL，检测限低至 5 个细胞/mL（S/N = 3）。通过二维材料和基于酶的双重信号放大，该生物传感器可能为实际样品中肿瘤细胞的高灵敏度检测开辟新途径。
