Peng Juanjuan, Liu Shaopu, Wang Lei, Liu Zhengwen, He Youqiu
Key Laboratory on Luminescence and Real-time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Beibei, Chongqing 400715, PR China.
J Colloid Interface Sci. 2009 Oct 15;338(2):578-83. doi: 10.1016/j.jcis.2009.06.055. Epub 2009 Jun 27.
Two different stabilizing agents thioglycolic acid (TGA) and L-cysteine (L-Cys) capped CdSe QDs with the diameter of 2 nm were synthesized, large amounts of stabilizing agents connected to CdSe QDs surface through Cd-S bond. The interaction between chitosan and QDs had been investigated, respectively. The interaction lead to the remarkable enhancement of RRS, RNLS and the enchantments were in proportional to the concentration of chitosan in a certain range. Under the optimal conditions, compared with TGA-CdSe QDs, the interaction between L-Cys-CdSe QDs with chitosan owned more broad linear range 0.042-3.0 microg mL(-1) and lower detect limits 1.2 ng mL(-1). The influences of factors on the interaction between chitosan with QDs and some foreign substances were all examined, which showed that the methods had a good sensitivity and selectivity. Based on this, it is hoped to build a method for the determination of chitosan using CdSe QDs as probes. Through Fourier transform infrared spectroscopy (FTIR) transmission electron microscopy (TEM), it was speculated that CdSe QDs interacted with chitosan to form a network structure aggregates through electrostatic attraction and hydrophobic forces. The reasons for the enhancement of RRS intensity were assumed as follows: resonance enhanced Rayleigh scattering effect, increase of the molecular volume, and hydrophobic effect.
合成了两种不同的稳定剂巯基乙酸（TGA）和L-半胱氨酸（L-Cys）包覆的直径为2 nm的CdSe量子点，大量稳定剂通过Cd-S键连接到CdSe量子点表面。分别研究了壳聚糖与量子点之间的相互作用。这种相互作用导致共振瑞利散射（RRS）、共振非线性散射（RNLS）显著增强，且在一定范围内增强程度与壳聚糖浓度成正比。在最佳条件下，与TGA-CdSe量子点相比，L-Cys-CdSe量子点与壳聚糖之间的相互作用具有更宽的线性范围0.042 - 3.0 μg mL⁻¹和更低的检测限1.2 ng mL⁻¹。考察了各种因素对壳聚糖与量子点相互作用以及一些外来物质的影响，结果表明该方法具有良好的灵敏度和选择性。基于此，有望建立一种以CdSe量子点为探针测定壳聚糖的方法。通过傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）推测，CdSe量子点与壳聚糖通过静电吸引和疏水作用相互作用形成网络结构聚集体。RRS强度增强的原因假定如下：共振增强瑞利散射效应、分子体积增大和疏水效应。
