Sensitive imaging of microRNA in living cells is of great value for disease diagnostics and prognostics. While signal amplification-based strategies have been developed for imaging low-abundance disease-relevant microRNA molecules, precise temporal control over sensor activity in living cells still remains a challenge, and limits their applications for sensing microRNA concentration dynamics. Herein, we report a class of photocaged nanoparticle sensors for highly sensitive imaging of microRNA in living cells with temporal control. The sensor features a DNA-templated gold nanoparticle-quantum dot satellite nanostructure which is temporarily inactivated by a photocaged DNA mask. Upon UV light irradiation, the sensor restores its activity for catalytic sensing of microRNA in living cells via entropy-driven two-step toehold-mediated strand displacement reactions. We show that the sensor exhibits quick response to UV light, robust intracellular stability, and high specificity and sensitivity for the microRNA target. On the basis of this strategy, precise control over sensor activity is achieved using an external light trigger, where on-demand sensing could be potentially performed with spatiotemporal control.

中文翻译：

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光笼式纳米颗粒传感器，用于通过时间控制在活癌细胞中进行敏感的microRNA成像

活细胞中microRNA的灵敏成像对疾病的诊断和预后具有重要的价值。虽然已经开发出基于信号放大的策略来成像低丰度疾病相关的microRNA分子，但是对活细胞中的传感器活动进行精确的时间控制仍然是一个挑战，并限制了它们在检测microRNA浓度动态方面的应用。在本文中，我们报告了一类光笼式纳米颗粒传感器，用于在具有时间控制的活细胞中对microRNA进行高度灵敏的成像。该传感器具有DNA模板化的金纳米粒子-量子点卫星纳米结构，该结构可通过光笼DNA掩模暂时失活。在紫外线照射下，该传感器通过熵驱动的两步脚趾介导的链置换反应，恢复了其对活细胞中微小RNA的催化传感的活性。我们表明该传感器表现出对紫外线的快速响应，强大的细胞内稳定性以及对microRNA靶标的高特异性和敏感性。基于此策略，可以使用外部光触发器实现对传感器活动的精确控制，其中可以通过时空控制潜在地执行按需传感。