MOE Key Laboratory of Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Institute of Nanomedicine and Nanobiosensing, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
MOE Key Laboratory of Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Institute of Nanomedicine and Nanobiosensing, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
Biosens Bioelectron. 2018 Oct 15;117:474-479. doi: 10.1016/j.bios.2018.06.056. Epub 2018 Jun 28.
A sensitive and homogeneous electrochemical aptasensor was fabricated for the detection of mucin 1 (MUC1) by combining a well-designed DNA bulge-loop (L-DNA) structure with high-efficient exonuclease I (Exo I)-assisted target recycling amplification strategy. The L-DNA probe was constructed via the hybridization of the MUC1 aptamer and methylene blue (MB) labeled complementary DNA (cDNA) (cDNA-MB) and hence could not diffuse freely to the negatively charged ITO electrode surface due to the strong electrostatic repulsion, so small electrochemical signal was detected. The addition of MUC1 caused the dissociation of L-DNA structure due to the specificity between aptamer and MUC1. Then Exo I was implemented to digest the released cDNA-MB into mononucleotides and then produced short MB-labeled mononucleotides fragments (MB-MFs). As the MB-MFs contained few negative charges, it diffused easily to the negatively charged ITO electrode surface and resulted in the enhanced electrochemical signal. Meanwhile, the MUC1-aptamer complex was also specifically digested by Exo I, resulting in the liberation of MUC1 and hence realized the target recycling and then caused the amplification of the electrochemical signal. The enhanced electrochemical signal has a good linear relationship with logarithm of MUC1 concentration in the range of 1.0 pg mL-50 ng mL with a limit of detection of 0.40 pg mL (S/N = 3). Additionally, the fabricated aptasensor has been successfully applied to detect MUC1 in serum samples with satisfactory results and thereby it exhibits great potential in the practical application of clinical diagnosis.
一种敏感且均相的电化学适体传感器通过结合精心设计的 DNA 突环（L-DNA）结构和高效的外切酶 I（Exo I）辅助目标循环放大策略，用于检测黏蛋白 1（MUC1）。L-DNA 探针通过 MUC1 适体和亚甲基蓝（MB）标记的互补 DNA（cDNA）（cDNA-MB）的杂交构建，由于强静电排斥，不能自由扩散到带负电荷的 ITO 电极表面，因此检测到的电化学信号较小。加入 MUC1 后，由于适体和 MUC1 之间的特异性，导致 L-DNA 结构解离。然后实施 Exo I 将释放的 cDNA-MB 消化成单核苷酸，然后产生短的 MB 标记的单核苷酸片段（MB-MFs）。由于 MB-MFs 带较少的负电荷，因此容易扩散到带负电荷的 ITO 电极表面，导致电化学信号增强。同时，MUC1-适体复合物也被 Exo I 特异性地消化，导致 MUC1 的释放，从而实现了目标的循环，并导致电化学信号的放大。增强的电化学信号与 MUC1 浓度的对数在 1.0 pg/mL-50 ng/mL 的范围内呈良好的线性关系，检出限为 0.40 pg/mL（S/N = 3）。此外，该适体传感器已成功应用于血清样品中 MUC1 的检测，结果令人满意，因此在临床诊断的实际应用中具有很大的潜力。
