Shandong Provincial Key Laboratory of Detection Technology for Tumor Markers, College of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, P. R. China.
J Mater Chem B. 2024 Nov 13;12(44):11381-11388. doi: 10.1039/d4tb01703j.
Sensitive imaging of microRNAs (miRNAs) in tumor cells holds great significance in the domains of pathology, drug development, and personalized diagnosis and treatment. DNA nanostructures possess excellent biostability and programmability and are suitable as carriers for intracellular imaging probes. With its highly controllable motion mechanism and remarkable target recognition specificity, the DNA walker is an ideal tool for living cell imaging. Here, we report a DNA nanowire based-DNAzyme Walker (D-Walker), which loads the DNAzyme based-molecular beacon (D-MB) onto DNA nanowires (NWs) functionalized with aptamers. The experimental results demonstrated that the intracellular target miRNA can specifically activate the pre-locked DNAzyme through a strand displacement reaction, thereby triggering the cleavage of its substrate molecular beacon (MB) and subsequent fluorescence emission. NWs decorated with aptamers can effectively prevent the degradation of the D-Walker by nuclease, and can enter target cells without any transfection reagents, which enhances the stability and reliability of cell imaging. Furthermore, the D-Walker exhibited a remarkable sensitivity with a limit of detection (LOD) of 61 pM and was capable of distinguishing miRNA-21 from other closely related family members. This study provides a novel strategy for intracellular miRNA imaging, offering a promising tool for cancer diagnosis and treatment.
在病理学、药物开发以及个性化诊断和治疗领域，对肿瘤细胞中的 microRNAs（miRNAs）进行敏感成像具有重要意义。DNA 纳米结构具有极好的生物稳定性和可编程性，适合作为细胞内成像探针的载体。DNA walker 具有高度可控的运动机制和显著的目标识别特异性，是活细胞成像的理想工具。在这里，我们报告了一种基于 DNA 纳米线的 DNA 酶 Walker（D-Walker），它将基于 DNA 酶的分子信标（D-MB）加载到与适体功能化的 DNA 纳米线上。实验结果表明，细胞内靶标 miRNA 可以通过链置换反应特异性地激活预锁定的 DNA 酶，从而触发其底物分子信标的切割和随后的荧光发射。用适体修饰的 NWs 可以有效地防止核酶对 D-Walker 的降解，并且可以在没有任何转染试剂的情况下进入靶细胞，从而增强了细胞成像的稳定性和可靠性。此外，D-Walker 表现出显著的灵敏度，检测限（LOD）为 61 pM，并且能够区分 miRNA-21 与其他密切相关的家族成员。本研究为细胞内 miRNA 成像提供了一种新策略，为癌症诊断和治疗提供了一种有前途的工具。
