The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou, 215123, P. R. China.
ACS Sens. 2018 Feb 23;3(2):494-503. doi: 10.1021/acssensors.7b00922. Epub 2018 Feb 7.
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.
活细胞中 microRNA 的敏感成像对于疾病的诊断和预后具有重要价值。虽然已经开发出基于信号放大的策略来对低丰度与疾病相关的 microRNA 分子进行成像，但在活细胞中对传感器活性进行精确的时间控制仍然是一个挑战，这限制了它们在检测 microRNA 浓度动态方面的应用。在此，我们报告了一类光笼纳米颗粒传感器，用于具有时间控制的活细胞中 microRNA 的高灵敏度成像。该传感器具有 DNA 模板化的金纳米颗粒-量子点卫星纳米结构，其通过光笼 DNA 掩模暂时失活。在紫外光照射下，传感器通过熵驱动的两步引发的链置换反应恢复其在活细胞中催化检测 microRNA 的活性。我们表明，该传感器对紫外光具有快速响应，在细胞内具有很强的稳定性，并且对 microRNA 靶标具有很高的特异性和灵敏度。在此基础上，我们利用外部光触发实现了对传感器活性的精确控制，从而可以实现按需进行时空控制的传感。
