Target-triggered “signal-off” electrochemical aptasensor assisted by Au nanoparticle–modified sensing platform for high-sensitivity determination of circulating tumor cells
Target-triggered “signal-off” electrochemical aptasensor assisted by Au nanoparticle–modified sensing platform for high-sensitivity determination of circulating tumor cells
复制标题
DOI：
10.1007/s00216-020-02940-x
复制
发表时间：
2020-09
影响因子：
4.3
通讯作者：
Yang Wang;Wenqing Zhang;Xiaoqi Tang;Yunxia Wang;Weiling Fu;Kai Chang;Ming Chen
中科院分区：
文献类型：
--
作者：
Yang Wang;Wenqing Zhang;Xiaoqi Tang;Yunxia Wang;Weiling Fu;Kai Chang;Ming Chen
在这项研究中，我们构建了一个高灵敏度的“信号关闭”电化学感应平台，用于基于靶触发的亚甲基蓝（MB）信号读出来定量循环肿瘤细胞（ctc）。引入Au纳米颗粒（AuNPs）可以扩大金电极（GE）的比表面积，从而固定更多的均匀mb适配体。mb修饰和茎环样适配体被指定为K562细胞的识别元件。巯基化的互补链与MB适配体杂交形成双链DNA （dsDNA）构象，在aunp修饰的GE表面进一步自组装，导致MB信号出现明显的电流峰。在K562细胞存在的情况下，mb -适体倾向于识别并与细胞结合，导致mb -适体从GE表面脱落。因此，MB信号的降低值与K562细胞的数量有关。在1 × 102 ~ 1 × 106cells mL - 1的动态线性范围内，检测限为23 cells mL - 1。此外，该适体传感器表现出良好的选择性、稳定性和可重复性，在临床环境中具有潜在的应用前景。同时，利用场发射扫描电镜、能量色散x射线能谱、原子力显微镜、循环伏安法和电化学阻抗谱等表征技术分析了所构建的适体传感器的形貌演变和各制备步骤。我们提出的适体传感器可以替代肿瘤细胞特异性适体，作为CTC检测的通用平台，在基础研究和临床应用中具有广阔的前景。图形抽象
In this study, we fabricated a high-sensitivity “signal-off” electrochemical aptasensing platform for quantifying circulating tumor cells (CTCs) based on target-triggered signal readout of methylene blue (MB). Au nanoparticles (AuNPs) were introduced to enlarge the specific surface area of the gold electrode (GE), which would immobilize homogeneous and more MB-aptamers. MB-modified and stem-loop-like aptamers were assigned as a recognition element with K562 cells. Thiolated complementary strands hybridized with MB-aptamers to form double-stranded DNA (dsDNA) conformation which were further self-assembled on the surface of AuNP-modified GE, leading to a marked current peak of MB signal. In the presence of K562 cells, the MB-aptamers preferred to recognize and bind with the cells, causing the disassembly of MB-aptamers from the GE surface. Therefore, the reduced value of MB signal was related to the number of K562 cells. With the proposed aptasensor, a dynamic linear range from 1 × 102to 1 × 106cells mL−1was obtained with a detection limit of 23 cells mL−1. Moreover, the aptasensor showed good selectivity, stability, and reproducibility as well as potential use in the clinical setting. Meanwhile, characterization techniques such as field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were performed to analyze the evolution of the morphology and each fabricated step of the constructed aptasensor. Our proposed aptasensor could be designed as a universal platform for CTC determination by replacing tumor cell–specific aptamers, which is a promising strategy for basic research and clinical applications.Graphical abstract