A highly loaded and integrated core–brush three-dimensional (3D) DNA nanostructure is constructed by programmatically assembling a locked DNA walking arm (DA) and hairpin substrate (HS) into a repetitive array along a well-designed DNA track generated by rolling circle amplification (RCA) and is applied as a 3D DNA nanomachine for rapid and sensitive intracellular microRNA (miRNA) imaging and sensing. Impressively, the homogeneous distribution of the DA and HS at a ratio of 1 : 3 on the DNA track provides a specific walking range for the DA to avoid invalid and random self-walking and notably improve the executive ability of the core–brush 3D DNA nanomachine, which easily solves the major technical challenges of traditional Au-based 3D DNA nanomachines: low loading capacity and low executive efficiency. As a proof of concept, the interaction of miRNA with the 3D DNA nanomachine could initiate the autonomous and progressive operation of the DA to cleave the HS for ultrasensitive ECL detection of target miRNA-21 with a detection limit as low as 3.57 aM and rapid imaging in living cells within 15 min. Therefore, the proposed core–brush 3D DNA nanomachine could not only provide convincing evidence for sensitive detection and rapid visual imaging of biomarkers with tiny change, but also assist researchers in investigating the formation mechanism of tumors, improving their recovery rates and reducing correlative complications. This strategy might enrich the method to design a new generation of 3D DNA nanomachine and promote the development of clinical diagnosis, targeted therapy and prognosis monitoring.

中文翻译：

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核心刷 3D DNA 纳米结构：用于细胞内 microRNA 超灵敏传感和快速动力学成像的下一代 DNA 纳米机器

通过将锁定的 DNA 行走臂 (DA) 和发夹底物 (HS) 沿着滚动圈生成的精心设计的 DNA 轨道以编程方式组装成重复阵列，构建了高负载和集成的核心刷式三维 (3D) DNA 纳米结构放大 (RCA) 并被用作 3D DNA 纳米机器，用于快速和灵敏的细胞内 microRNA (miRNA) 成像和传感。令人印象深刻的是，DA 和 HS 在 DNA 轨道上以 1:3 的比例均匀分布，为 DA 提供了特定的行走范围，以避免无效和随机的自我行走，显着提高核心刷 3D DNA 的执行能力纳米机器，轻松解决了传统金基3D DNA纳米机器的主要技术挑战：低负载能力和低执行效率。作为概念证明，miRNA 与 3D DNA 纳米机器的相互作用可以启动 DA 的自主和渐进操作，以切割 HS，用于超灵敏 ECL 检测目标 miRNA-21，检测限低至 3.57 aM，并在 15 分钟内快速成像活细胞因此，所提出的核心刷3D DNA纳米机器不仅可以为微小变化的生物标志物的灵敏检测和快速视觉成像提供令人信服的证据，而且可以帮助研究人员研究肿瘤的形成机制，提高其恢复率并减少相关并发症。该策略可能会丰富新一代3D DNA纳米机器的设计方法，促进临床诊断、靶向治疗和预后监测的发展。