Fukuda Takeshi, Kurabayashi Tomokazu, Funaki Nayuta, Udaka Hikari, Suzuki Miho
Department of Functional Materials Science, Saitama University.
Anal Sci. 2016;32(5):529-34. doi: 10.2116/analsci.32.529.
Conjugates of semiconductor quantum dots (QDs) and organic dyes have been receiving attention as fluorescence biological sensing materials. In designing such sensors, a most important parameter is the number of organic-dye molecules that conjugate to a QD. If a precise separation method was developed, it might be possible to control conjugation without knowing the exact number of conjugated dye molecules per QD. In this study, the difference in linear velocities in a gel filtration column between CdSe/ZnS QDs and 5-(and 6)-carboxynaphthofluorescein succinimidyl ester is used. The velocities differ because the hydrophilicity of CdSe/ZnS QDs is much higher than that of the organic dye; hence, CdSe/ZnS-organic-dye conjugation can be controlled by changing the fraction number. Furthermore, the concentrations of CdSe/ZnS QDs and organic dye in fractionated solutions can be determined by measuring fluorescence spectra, and we demonstrate a fluorescence-type pH sensor based on the conjugate, which has a pH-sensitivity range from 7.5 - 9.5.
半导体量子点（QD）与有机染料的共轭物作为荧光生物传感材料受到了关注。在设计此类传感器时，一个最重要的参数是与量子点共轭的有机染料分子数量。如果开发出一种精确的分离方法，那么即使不知道每个量子点上共轭染料分子的确切数量，也有可能控制共轭过程。在本研究中，利用了CdSe/ZnS量子点与5-（和6）-羧基萘荧光素琥珀酰亚胺酯在凝胶过滤柱中的线速度差异。速度不同是因为CdSe/ZnS量子点的亲水性远高于有机染料；因此，可以通过改变级分数来控制CdSe/ZnS-有机染料的共轭。此外，通过测量荧光光谱可以确定分级溶液中CdSe/ZnS量子点和有机染料的浓度，并且我们展示了一种基于该共轭物的荧光型pH传感器，其pH敏感范围为7.5至9.5。
