Zhang Yue, Zhang Yue, Zhang Xiaobo, Li Yuyi, He Yuling, Liu Ying, Ju Huangxian
State Key Laboratory of Analytical Chemistry for Life Science , School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China.
Chemistry and Biomedicine Innovation Center , Nanjing University , Nanjing 210023 , China . Email:
Chem Sci. 2020 May 26;11(24):6289-6296. doi: 10.1039/d0sc00394h. eCollection 2020 Jun 28.
DNA nanomachines are capable of converting tiny triggers into autonomous accelerated cascade hybridization reactions and they have been used as a signal amplification strategy for intracellular imaging. However, the "always active" property of most DNA nanomachines with an "absolute intensity-dependent" signal acquisition mode results in "false positive signal amplification" by extracellular analytes and impairs detection accuracy. Here we design a photo zipper locked miRNA responsive DNA nanomachine (PZ-DNA nanomachine) based on upconversion nanoparticles (UCNPs) with a photo-cleavable DNA strand to block the miRNA recognition region, which provided sufficient protection to the DNA nanomachine against nonspecific extracellular activation and allowed satisfactory signal amplification for sensitive miRNA imaging after intracellular photoactivation. Multiple emissions from the UCNPs were also utilized as an internal standard to self-calibrate the intracellular miRNA responsive fluorescence signal. The presented PZ-DNA nanomachine demonstrated the sensitive imaging of intracellular miRNA from different cell lines, which resulted in good accordance with qRT-PCR measurements, providing a universal platform for precise imaging in living cells with high spatial-temporal specificity.
DNA纳米机器能够将微小的触发信号转化为自主加速的级联杂交反应，并且它们已被用作细胞内成像的信号放大策略。然而，大多数具有“绝对强度依赖性”信号采集模式的DNA纳米机器的“始终活跃”特性会导致细胞外分析物产生“假阳性信号放大”，并损害检测准确性。在此，我们基于上转换纳米颗粒（UCNP）设计了一种光拉链锁定的miRNA响应DNA纳米机器（PZ-DNA纳米机器），其带有一条可光裂解的DNA链以阻断miRNA识别区域，这为DNA纳米机器提供了足够的保护，使其免受细胞外非特异性激活，并在细胞内光激活后实现了令人满意的信号放大，用于灵敏的miRNA成像。UCNP的多种发射还被用作内标，以自校准细胞内miRNA响应荧光信号。所展示的PZ-DNA纳米机器证明了对来自不同细胞系的细胞内miRNA的灵敏成像，这与qRT-PCR测量结果高度一致，为在活细胞中进行具有高时空特异性的精确成像提供了一个通用平台。
