Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States.
Anal Chem. 2011 Aug 1;83(15):5957-64. doi: 10.1021/ac201321m. Epub 2011 Jul 13.
A bifunctional oligonucleotide integrates in situ synthesis of a fluorogenic silver cluster with recognition of a target DNA sequence. With the template C(3)AC(3)AC(3)GC(3)A, a complex forms with 10 silver atoms that possesses electronic transitions in the near-infrared and that is detected at nanomolar concentrations using diode laser excitation. Pendant to this cluster encoding region, the recognition component binds a target DNA strand through hybridization, and decoupling of these two regions of the composite sensor renders a modular sensor for specific oligonucleotides. A target is detected using a quencher strand that bridges the cluster template and recognition components and disturbs cluster binding, as indicated by static quenching. Competitive displacement of the quencher by the target strand restores the favored cluster environment, and our key finding is that this exchange enhances emission through a proportional increase in the number of emissive clusters. DNA detection is also accomplished in serum-containing buffers by taking advantage of the high brightness of this fluorophore and the inherently low endogenous background in the near-infrared spectral region. Cluster stability in this biological environment is enhanced by supplementing the solutions with Ag(+).
一种双功能寡核苷酸将荧光银簇的原位合成与靶 DNA 序列的识别结合在一起。在模板 C(3)AC(3)AC(3)GC(3)A 的作用下，形成了一个包含 10 个银原子的复合物，该复合物具有近红外电子跃迁，并且可以在纳摩尔浓度下使用二极管激光激发进行检测。在这个簇编码区域旁边，识别组件通过杂交与靶 DNA 链结合，而复合传感器的这两个区域的解耦则提供了一种用于特定寡核苷酸的模块化传感器。通过桥接簇模板和识别组件的猝灭剂链来检测靶标，并通过静态猝灭来干扰簇的结合，从而指示出目标的存在。通过竞争取代猝灭剂，恢复了有利的簇环境，我们的关键发现是，这种交换通过发射簇数量的比例增加增强了发射。通过利用这种荧光团的高亮度和近红外光谱区域固有的低内源性背景，在含血清的缓冲液中也可以完成 DNA 检测。通过在溶液中补充 Ag(+)，可以增强簇在这种生物环境中的稳定性。
