Ludwig-Maximilians-Universitat Munchen, Amalienstrasse 54, 80799 Munich, Germany.
ACS Nano. 2009 Dec 22;3(12):4127-31. doi: 10.1021/nn901324y.
Electrostatic complexes of a water-soluble fluorescent conjugated polymer, poly[9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)propyl)-2,7-fluorene-alt-1,4-phenylene]dibromide (PDFD), and water-soluble CdTe quantum dots (QDs) are designed to provide a cascaded FRET for DNA hybridization detection. PDFD has two functions in the detection scheme: as a light-harvesting antenna, it enhances the emission of QDs by the first level FRET and inverts the sign of the surface charge of QDs, thus providing a positively charged surface to allow negatively charged dye-labeled DNA to interact with the resulting complex. This interaction causes the second level FRET to infrared-emitting dye labeled on the probe DNA, providing a reliable signal-on sensing platform discriminating between complementary and non-complementary DNA. A detailed spectroscopic study offers a clear description of photophysical processes in the designed polymer/QD/DNA complex, providing ample potential for further sensitivity and selectivity improvements.
设计了一种水溶性荧光共轭聚合物聚[9,9-双(3'-(N,N-二甲基)-N-乙基铵丙基)-2,7-芴并[9,1,3,def]噻二唑-1,4-亚苯基]二溴化物(PDFD)和水溶性 CdTe 量子点(QD)的静电复合物，为 DNA 杂交检测提供级联 FRET。在检测方案中，PDFD 具有两个功能：作为光收集天线，它通过第一级 FRET 增强 QD 的发射，并反转 QD 的表面电荷的符号，从而提供带正电荷的表面，允许带负电荷的染料标记 DNA 与所得复合物相互作用。这种相互作用导致第二级 FRET 到探针 DNA 上标记的红外发射染料，提供了一种可靠的信号开启感应平台，可区分互补和非互补 DNA。详细的光谱研究清楚地描述了设计的聚合物/QD/DNA 复合物中的光物理过程，为进一步提高灵敏度和选择性提供了充分的潜力。
