Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China.
Anal Chem. 2014 Feb 18;86(4):2124-30. doi: 10.1021/ac4037262. Epub 2014 Feb 4.
There remains a great challenge in the sensitive detection of microRNA because of the short length and low abundance of microRNAs in cells. Here, we have demonstrated an ultrasensitive detection platform for microRNA by combining the tetrahedral DNA nanostructure probes and hybridization chain reaction (HCR) amplification. The detection limits for DNA and microRNA are 100 aM and 10 aM (corresponding to 600 microRNAs in a 100 μL sample), respectively. Compared to the widely used supersandwich amplification, the detection limits are improved by 3 orders of magnitude. The uncontrolled surface immobilization and consumption of target molecules that limit the amplification efficiency of supersandwich are eliminated in our platform. Taking advantage of DNA nanotechnology, we employed three-dimensional tetrahedral DNA nanostructure as the scaffold to immobilize DNA recognition probes to increase the reactivity and accessibility, while DNA nanowire tentacles are used for efficient signal amplification by capturing multiple catalytic enzymes in a highly ordered way. The synergetic effect of DNA tetrahedron and nanowire tentacles have proven to greatly improve sensitivity for both DNA and microRNA detection.
由于细胞中 microRNA 的长度短、丰度低，因此对其进行敏感检测仍然是一个巨大的挑战。在这里，我们通过结合四面体形 DNA 纳米结构探针和杂交链式反应（HCR）扩增，展示了一种用于 microRNA 的超灵敏检测平台。该平台对 DNA 和 microRNA 的检测限分别为 100 aM 和 10 aM（对应于 100 μL 样品中的 600 个 microRNAs）。与广泛使用的超三明治扩增相比，检测限提高了 3 个数量级。在我们的平台中，消除了限制超三明治扩增效率的目标分子的不可控表面固定化和消耗。利用 DNA 纳米技术，我们采用三维四面体 DNA 纳米结构作为支架来固定 DNA 识别探针，以提高反应性和可及性，而 DNA 纳米线触手则用于通过以高度有序的方式捕获多个催化酶来进行有效的信号放大。DNA 四面体和纳米线触手的协同效应已被证明可大大提高 DNA 和 microRNA 检测的灵敏度。
