School of Chemistry and Environment, South China Normal University, Guangzhou 510631, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 May;75(5):1617-23. doi: 10.1016/j.saa.2010.02.030. Epub 2010 Feb 24.
The CdSe quantum dots (QDs) modified by mercapto-beta-cyclodextrin (CD) were synthesized and characterized by transmission electron microscopy, powder X-ray diffraction, excitation and emission spectra, and fluorescence lifetime. When lambda(ex)=370nm, the fluorescence peak of CdSe/CD QDs is at 525nm. Phenanthroline (Phen) is able to quench their fluorescence, which can be recovered by the addition of DNA. The quenching and restoration of fluorescence intensity were found to be linearly proportional to the amount of Phen and DNA, respectively. The variation of the fluorescence intensity of the CdSe/CD QDs-Phen system was studied, and it was demonstrated to result from a static mechanism due to the formation of a Phen inclusion complex with the CdSe QDs modified by mercapto-beta-cyclodextrin. The fluorescence recovery was due to the binding of DNA with Phen in the inclusion complex, leading to the freeing of the CdSe/CD QDs. The binding constants and sizes of the binding sites of the Phen-DNA interaction were calculated to be 1.33x10(7)mol(-1)L and 10.79bp.
巯基-β-环糊精（CD）修饰的 CdSe 量子点（QDs）通过透射电子显微镜、粉末 X 射线衍射、激发和发射光谱以及荧光寿命进行了合成和表征。当 lambda(ex)=370nm 时，CdSe/CD QDs 的荧光峰位于 525nm。菲咯啉（Phen）能够猝灭它们的荧光，而添加 DNA 可以使其恢复。发现荧光强度的猝灭和恢复与 Phen 和 DNA 的量分别呈线性关系。研究了 CdSe/CD QDs-Phen 体系荧光强度的变化，结果表明，由于形成了与巯基-β-环糊精修饰的 CdSe QDs 的 Phen 包合物，因此荧光强度的变化是由于静态机制引起的。荧光恢复是由于 DNA 与包含复合物中的 Phen 结合，导致 CdSe/CD QDs 的释放。计算了 Phen-DNA 相互作用的结合常数和结合位点大小，分别为 1.33x10(7)mol(-1)L 和 10.79bp。
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