Lu Hanwen, Hailin Tang, Yi Xinyao, Wang Jianxiu
Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan P. R. China 410083.
SunYat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong P. R. China 510060.
Langmuir. 2020 Sep 15;36(36):10708-10714. doi: 10.1021/acs.langmuir.0c01415. Epub 2020 Sep 1.
MicroRNA (miRNA) serves as an ideal biomarker for diagnosis, prognosis, and therapy of various human cancers. The rationally designed three-dimensional (3D) DNA nanomachine was constructed on the matrixes of magnetic beads, and the high density of gold nanoparticles (AuNPs) on each magnetic bead and further enlargement of the AuNPs lead to the anchoring of numerous DNA walkers and signal probes on the AuNPs. With the combination of toehold-mediated strand displacement reaction (SDR), amplified electrochemical detection of miRNA is performed. The existence of miRNA triggers the toehold-mediated SDR and the released DNA walker probe is hybridized with the ferrocene (Fc)-tagged signal probe. The cleavage of the duplex by the nicking endonuclease detaches the signal probe from the magnetic nanocomposites. The oxidation current of Fc moieties was found to be inversely proportional to the concentrations of miRNA-182 between 1.0 fM and 2 pM. The assay is highly selective for discrimination of miRNAs with similar sequences. The feasibility of the method for sensitive detection of the expression levels of miRNA-182 from serum samples of glioma patients at different stages was demonstrated. The sensing protocol holds great promise for early diagnosis and prognosis of the cancer cases with abnormal miRNA expression.
微小RNA（miRNA）是各种人类癌症诊断、预后和治疗的理想生物标志物。在磁珠基质上构建了合理设计的三维（3D）DNA纳米机器，每个磁珠上高密度的金纳米颗粒（AuNP）以及AuNP的进一步扩大导致大量DNA步行器和信号探针锚定在AuNP上。结合链置换反应（SDR），实现了对miRNA的电化学放大检测。miRNA的存在触发了链置换反应，释放的DNA步行器探针与二茂铁（Fc）标记的信号探针杂交。切口内切酶对双链体的切割使信号探针从磁性纳米复合材料上分离。发现Fc部分的氧化电流与1.0 fM至2 pM之间的miRNA-182浓度成反比。该检测方法对具有相似序列的miRNA具有高度选择性。证明了该方法用于灵敏检测不同阶段胶质瘤患者血清样本中miRNA-182表达水平的可行性。该传感方案对miRNA表达异常的癌症病例的早期诊断和预后具有很大的前景。
