Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou 350002, China.
Cancer Metastasis Alert and Prevention Center, and Pharmaceutical Photocatalysis of State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, China; Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou 350002, China.
Biosens Bioelectron. 2016 Dec 15;86:1024-1030. doi: 10.1016/j.bios.2016.07.029. Epub 2016 Jul 9.
In the present study, we proposed a novel dual-cyclical nucleic acid strand-displacement polymerization (dual-CNDP) based signal amplification system for highly sensitive determination of tumor suppressor genes. The system primarily consisted of a signaling hairpin probe (SHP), a label-free hairpin probe (LHP) and an initiating primer (IP). The presence of target DNA was able to induce one CNDP through continuous process of ligation, polymerization and nicking, leading to extensively accumulation of two nicked triggers (NT1 and NT2). Intriguingly, the NT1 could directly hybridize SHP, while the NT2 could act as the target analog to induce another CNDP. The resulting dual-CNDP contributed the striking signal amplification, and only a very weak blank noise existed since the ligation template of target was not involved. In this case, the target could be detected in a wide linear range (5 orders of magnitude), and a low detection limit (78 fM) was obtained, which is superior to most of the existing fluorescent methods. Moreover, the dual-CNDP sensing system provided a high selectivity towards target DNA against mismatched target and was successfully applied to analysis of target gene extracted from cancer cells or in human serum-contained samples, indicating its great potential for practical applications.
在本研究中，我们提出了一种新颖的基于双循环核酸链置换聚合（dual-CNDP）的信号放大系统，用于高灵敏度测定肿瘤抑制基因。该系统主要由信号发夹探针（SHP）、无标记发夹探针（LHP）和起始引物（IP）组成。靶 DNA 的存在能够通过连续的连接、聚合和缺口反应诱导一次 CNDP，导致两个缺口触发物（NT1 和 NT2）的广泛积累。有趣的是，NT1 可以直接与 SHP 杂交，而 NT2 可以作为靶标类似物诱导另一次 CNDP。由此产生的双 CNDP 贡献了显著的信号放大，由于不涉及靶标连接模板，因此仅存在非常微弱的空白噪声。在这种情况下，目标可以在很宽的线性范围内（5 个数量级）进行检测，并且可以获得低检测限（78 fM），优于大多数现有的荧光方法。此外，dual-CNDP 传感系统对靶 DNA 具有高选择性，能够区分错配的靶标，并成功应用于从癌细胞中提取的靶基因或含有人血清的样品中的分析，表明其在实际应用中有很大的潜力。
