State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, China.
Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Laboratory of Fiber Materials and Modern Textiles, the Growing Base for State Key Laboratory, Qingdao University , Qingdao 266071, China.
ACS Appl Mater Interfaces. 2016 Oct 12;8(40):26532-26540. doi: 10.1021/acsami.6b08597. Epub 2016 Sep 30.
Due to the predictable conformation and programmable Watson-Crick base-pairing interactions, DNA has proven to be an attractive material to construct various nanostructures. Herein, we demonstrate a simple model of DNA polymerase-directed hairpin assembly (PDHA) to construct DNA nanoassemblies for versatile applications in biomedicine and biosensing. The system consists of only two hairpins, an initiator and a DNA polymerase. Upon addition of aptamer-linked initiator, the inert stems of the two hairpins are activated alternately under the direction of DNA polymerase, which thus grows into aptamer-tethered DNA nanoassemblies (AptNAs). Moreover, through incorporating fluorophores and drug-loading sites into the AptNAs, we have constructed multifunctional DNA nanoassemblies for targeted cancer therapy with high drug payloads and good biocompatibility. Interestingly, using the as-prepared AptNAs as building blocks, DNA nanohydrogels are self-assembled after centrifugation driven by liquid crystallization and dense packaging of DNA duplexes. Taking advantage of easy preparation and high loading capacity, the PDHAs are readily extended to the fabrication of a label-free biosensing platform, achieving amplified electrochemical detection of microRNA-21 (miR-21) with a detection limit as low as 0.75 fM and a dynamic range of 8 orders of magnitude. This biosensor also demonstrates excellent specificity to discriminate the target miR-21 from the control microRNAs and even the one-base mismatched one and further performs well in analyzing miR-21 in MCF-7 tumor cells.
由于 DNA 具有可预测的构象和可编程的 Watson-Crick 碱基配对相互作用，因此已被证明是构建各种纳米结构的有吸引力的材料。在此，我们展示了一种简单的 DNA 聚合酶指导发夹组装（PDHA）模型，用于构建用于生物医学和生物传感的多功能 DNA 纳米组装体。该系统仅由两个发夹组成，一个启动子和一个 DNA 聚合酶。在添加与适体连接的启动子时，在 DNA 聚合酶的指导下，两个发夹的惰性茎交替被激活，从而生长成适体连接的 DNA 纳米组装体（AptNAs）。此外，通过将荧光团和药物加载位点纳入 AptNAs，我们构建了多功能 DNA 纳米组装体，用于具有高药物载量和良好生物相容性的靶向癌症治疗。有趣的是，使用所制备的 AptNAs 作为构建块，在由液晶驱动的离心力作用下，DNA 双链的紧密包装，自组装成 DNA 纳米水凝胶。利用易于制备和高载药能力，PDHAs 很容易扩展到制造无标记生物传感平台，实现了微 RNA-21（miR-21）的电化学放大检测，检测限低至 0.75 fM，动态范围为 8 个数量级。该生物传感器还表现出优异的特异性，能够区分靶 miR-21 与对照 microRNAs，甚至是一个碱基错配的 microRNAs，并且在 MCF-7 肿瘤细胞中分析 miR-21 时表现良好。
