Single-quantum-dot-based DNA nanosensor
Single-quantum-dot-based DNA nanosensor
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DOI：
10.1038/nmat1508
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发表时间：
2005-11-01
期刊：
影响因子：
41.2
通讯作者：
Wang, TH
中科院分区：
文献类型：
--
作者：
Zhang, CY;Yeh, HC;Wang, TH
快速和高灵敏度的DNA检测在诊断遗传性疾病中至关重要。常规方法通常依赖于靶DNA的繁琐的半定量扩增来提高检测灵敏度。此外，大多数DNA检测系统（例如微阵列），无论其是否需要靶扩增，都需要将未杂交的DNA链与固定在固体基质上的杂交链分离，因此溶液-表面结合动力学使其复杂化（1，2）。在这里，我们报告了一种基于荧光共振能量转移（FRET）的超灵敏纳米传感器，能够检测低浓度的DNA在分离的格式。该系统使用与DNA探针连接的量子点（QD）（3-5）来捕获DNA靶标。靶链与染料标记的报告链结合，从而形成FRET供体-受体系综。QD还用作通过在纳米级域中连接几个目标来放大目标信号的集中器。未结合的纳米传感器产生接近零的背景荧光，但即使与少量的靶DNA（类似于50个拷贝或更少）结合，它们也会产生非常明显的FRET信号。已证明基于纳米传感器的荧光标记物连接试验可成功检测临床样本中某些卵巢肿瘤的典型点突变（6）。
Rapid and highly sensitive detection of DNA is critical in diagnosing genetic diseases. Conventional approaches often rely on cumbersome, semi-quantitative amplification of target DNA to improve detection sensitivity. In addition, most DNA detection systems ( microarrays, for example), regardless of their need for target amplification, require separation of unhybridized DNA strands from hybridized stands immobilized on a solid substrate, and are thereby complicated by solution-surface binding kinetics(1,2). Here, we report an ultrasensitive nanosensor based on fluorescence resonance energy transfer ( FRET) capable of detecting low concentrations of DNA in a separation-free format. This system uses quantum dots ( QDs)(3-5) linked to DNA probes to capture DNA targets. The target strand binds to a dye-labelled reporter strand thus forming a FRET donor - acceptor ensemble. The QD also functions as a concentrator that amplifies the target signal by con. ning several targets in a nanoscale domain. Unbound nanosensors produce near-zero background fluorescence, but on binding to even a small amount of target DNA (similar to 50 copies or less)they generate a very distinct FRET signal. A nanosensor-based oligonucleotideligation assay has been demonstrated to successfully detect a point mutation(6) typical of some ovarian tumours in clinical samples.