DNA molecular probes have emerged as powerful tools for fluorescence imaging of microRNAs (miRNAs) in living cells and thus elucidating functions and dynamics of miRNAs. In particular, the highly integrated DNA probes that can be able to address the robustness, sensitivity and consistency issues in a single assay system were highly desired but remained largely unsolved challenge. Herein, we reported for the first time that the development of the novel DNA nanomachines that split-DNAzyme motif was highly integrated in a single DNA triangular prism (DTP) reactor and can undergo target-activated DNAzyme catalytic cascade circuits, allowing amplified sensing and imaging of tumor-related microRNA-21 (miR-21) in living cells. The DNA nanomachines have shown dynamic responses for target miR-21 with excellent sensitivity and selectivity and demonstrated the potential for living cell imaging of miR-21. With the advantages of facile modular design and assembly, high biostability, low cytotoxicity and excellent cellular internalization, the highly integrated DNA nanomachines enabled accurate and effective monitoring of miR-21 expression levels in living cells. Therefore, our developed strategy may afford a reliable and robust nanoplatform for tumor diagnosis and for related biological research.

DNA分子探针已成为强大的工具，可以对活细胞中的microRNA（miRNA）进行荧光成像，从而阐明miRNA的功能和动力学。尤其是，人们高度希望能够在单个测定系统中解决鲁棒性，灵敏度和一致性问题的高度整合的DNA探针，但仍面临很大的挑战。在本文中，我们首次报道了分裂DNAzyme基序高度集成在单个DNA三角棱镜（DTP）反应器中并且可以经历靶标激活的DNAzyme催化级联回路的新型DNA纳米机器的开发，从而可以进行放大的传感和成像活细胞中与肿瘤相关的microRNA-21（miR-21）的表达。DNA纳米机器以优异的灵敏度和选择性显示出对靶miR-21的动态响应，并展示了miR-21活细胞成像的潜力。凭借易于模块化设计和组装，高生物稳定性，低细胞毒性和出色的细胞内在化的优势，高度集成的DNA纳米机器能够准确有效地监测活细胞中miR-21的表达水平。因此，我们开发的策略可能为肿瘤诊断和相关生物学研究提供可靠而强大的纳米平台。高度集成的DNA纳米机器能够准确有效地监控活细胞中miR-21的表达水平。因此，我们开发的策略可能为肿瘤诊断和相关生物学研究提供可靠而强大的纳米平台。高度集成的DNA纳米机器能够准确有效地监控活细胞中miR-21的表达水平。因此，我们开发的策略可能为肿瘤诊断和相关生物学研究提供可靠而强大的纳米平台。