SiO2包覆铕(Ⅲ)配合物的荧光纳米粒子合成与性质

Preparation and Properties of SiO_2 Coating Europium (Ⅲ) Complex Fluorescent Nanoparticles

以前驱物pAB-DTPAA-APTEOS、正硅酸乙酯(TEOS)和三氯化铕(EuCl3)等为原料,采用油包水(W/O)的反相微乳液法,在正硅酸乙酯(TEOS)和3-氨丙基三乙氧基硅烷(APTEOS)的共同水解下,制备出新型的SiO2包覆铕配合物荧光纳米粒子Eu-pAB-DTPAA-AP-SiO2。运用TEM、IR、UV-Vis、荧光光谱等技术对荧光纳米粒子进行了表征。TEM结果表明:包覆体呈球形,分散均匀,平均粒径为40nm。纳米粒子与配体、前驱物的紫外吸收谱相比较,峰位发生了一定的红移,表明通过反相微乳液法得到的固体粉末与EuCl3反应后,已经生成配合物Eu-pAB-DTPAA-AP-SiO2。红外光谱研究表明,在801cm-1出现νSi—C的伸缩振动峰,471cm-1处出现νEu—O的伸缩振动峰。由此证实Eu-pAB-DTPAA-AP-SiO2配合物的存在。荧光光谱分析表明,纳米粒子Eu-pAB-DTPAA-AP-SiO2表现出较好的荧光性能,位于592,615,689nm的发射峰分别归属于Eu3+离子的5D0→7F1、5D0→7F2和5D0→7F4跃迁,其中最强峰615nm属于Eu3+的特征跃迁发射。作为一种新型的荧光试剂,该纳米粒子具有粒径小,亲水性强,荧光强度大,且表面的氨基能方便地与生物分子偶联,故可作为优良的时间分辨荧光标记物用于各种高灵敏生物检测技术中。

The incorporation of rare earth complex into inorganic hybrid host materials has been extensively explored in recent studies, especially focused on SiO2-based materials, and the obtained materials were found to show high improvements for their thermal, mechanical properties and chemical stability. Furthermore, the materials are nanometer-sized luminescent, and become a research attractions as luminescence probes in various types of biological detection. In this paper, the fluorescent nanoparticles were prepared with pAB-DTPAA-APTEOS precursor, TEOS and EuCl3 as raw materials by means of water-in-oil （W/O） microemulsion through controlling copolymerization of tetraethyl orthosilicate （TEOS） and 3-aminopropyl-triethyloxysilane （APTEOS）. Fluorescent nanopar- ticles were characterized with TEM, UV-vis, IR and fluorescence techniques. It can be seen from the TEM image of the phosphor that the fluorescent nanoparticles are spherical and better particle dispersity, with average particle size of 40 nm. The IR spectra of Eu-pAB-DTPAA-AP-SiO2 has two regions, which correspond to Si-C stretching （801 cm^-1） Eu-pAB-DTPAA-AP-SiO2. In th and Eu-O stretching （471 cm^-1）, this e UV-vis spectra, compared to the absorpti confirms the existence of complex on spectrum of pAB-DTPAA, a red shift of the first peak （from 232 nm to 260 nm） was found in the spectrum of the precursor （pAB-DTPAA-APTEOS）, no change was observed for the major at 336 nm, which indicates the information of pAB-DTPAA-APTEOS. Furthermore, after EuCl3 was added to the solution of pAB-DTPAA-APTEOS, the red shift phenomena of the absorption peaks were observed. These changes indicate that complex Eu-pAB-DTPAA-AP-SiO2 was formed in the pAB-DTPAA-APTEOS-EuCl3 solution. The excitation and emission spectra of the nanoparticles indicate that the excitation peak wavelength is at 260 nm and the emission peak wavelength is at 615 nm. When the nanoparticles were excited by 260 nm, only the emission lines of ^5 D0→7 Fj （ J = 1 - 4） of Eu^3 ＋ were observed, with the hypersensitive ^5D0→^7F2 transition as the most prominently single radiation peak without splitting. As a new analytical reagent, the fluorescent nanoparticles combine the advantages of luminophore-doped silica nanoparticle probe and lanthanide latex fluorescence probe including smaller size （ about 40 nm）, high hydrophilicity and biocompatibility. Furthermore, the amino groups directly introduced to the nanoparticles surface by using APTEOS in the preparation made the surface modification and bioconjugation of the nanoparticles easier. The particles are potential of good biocompatibility and can be excepted as efficient biological labels.