表面修饰的CdS纳米荧光探针的研究

采用溶胶-凝胶法合成硫脲表面修饰的硫化镉纳米粒子CdS/SC(NH₂)₂]，研究硫脲的用量对其粒径的影响，用X射线粉末衍射、透射电子显微镜，红外光谱以及荧光光谱等手段进行了表征。并研究了小牛胸腺DNA的加入对该纳米粒子荧光光谱的影响。实验结果表明，硫脲的用量对该纳米粒子的粒径大小及发光特性有明显影响，随反应物中硫脲与镉离子的物质的量的比值增加，CdS/SC(NH₂)₂纳米粒子粒径变小，其发射波长蓝移，表现出明显的量子尺寸特性;小牛胸腺DNA的加入使CdS/SC(NH₂)₂纳米粒子的发射光谱强度减弱，实验推测该纳米粒子与小牛胸腺DNA存在静电相互作用, 该研究结果可望用于DNA的分析测定。

Study on Surface-Capped CdS Nanoparticles as Fluorescence Probes

In the present paper,CdS nanoparticles of different size surface-capped with thiourea expressed as CdS/SC(NH_2)_2] were prepared by sol-gel method,and characterized by XRD,TEM,IR and PL.The results show that the molar ratio of thiourea to cadmium ion has influence on the size and luminescence properties of the nanoparticles.With increasing the mdar ratio of thiourea to cadmium ion in the reactant,the size of the nanoparticles decreases,and the maximum emission wavelength of the nanoparticles shows an obvious blue shift due to quantum confinement effect.The effect of calf thymus deoxyribonucleic acid(ct-DNA) on the fluorescence spectrum of the CdS/SC(NH_2)_2 nanoparticles was also studied.The result shows that the intensity of fluorescence spectrum of the nanoparticles is quenched by ct-DNA,which is probably caused by the electrostatic interaction(between) CdS/SC(NH_2)_2 nanoparticles and ct-DNA.The CdS/SC(NH_2)_2 nanoparticles are hopeful of being used as fluorescence probes in DNA determination.