Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, PR China.
Dalton Trans. 2011 Dec 28;40(48):12909-16. doi: 10.1039/c1dt11364j. Epub 2011 Oct 24.
Attapulgite, an extremely stable fibrillar mineral present in nature, is a promising new carrier of luminescent lanthanide complexes for further applications. A europium complex Eu(DBM)(3)(H(2)O)(2) (HDBM = dibenzoylmethane) was covalently coupled onto modified attapulgites (or silica nanoparticles) via a ligand exchange reaction, generating attapulgite-based ternary europium complexes. The composites were characterized by CHN elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for Eu(3+) content, powder X-ray diffraction (XRD), thermogravimetry (TG) and UV-vis absorption spectra. The results indicate that the Eu(3+) complex was grafted covalently to the outer surfaces of attapulgites (or silica nanoparticles) and modifications by coupling agents containing different alkoxide groups (aminopropyltriethoxysilane (APTES) or aminopropylmethyldiethoxysilane (APMDES)) led to different grafting ratios. The structures of these composites were further evidenced by the determination of photophysical behaviours and coordinated water molecules of the complexes linked to matrices. Attapulgite-based lanthanide composites linked by APTES can be excited by visible light, with a wide excitation wavelength range from UV to visible light (a maximum at 398 nm), long luminescence lifetime (503 μs), high quantum yield (48%) and improved exposure durability. When incubated with HeLa cells at 37 °C, the fluorescence of matrix-APTES-cpa-Eu(DBM)(3) is observed on the cell membrane. Moreover, the low cytotoxicity of our present system results in potential applications for cell imaging in biological systems.
凹凸棒石是一种在自然界中极为稳定的纤维状矿物，是一种很有前途的新型镧系元素配合物载体，可进一步应用。通过配体交换反应，将铕（Eu）配合物 Eu(DBM)(3)(H(2)O)(2)（HDBM=二苯甲酰甲烷）共价偶联到改性凹凸棒石（或二氧化硅纳米粒子）上，生成基于凹凸棒石的三元铕配合物。通过 CHN 元素分析、电感耦合等离子体原子发射光谱（ICP-AES）测定 Eu(3+)含量、粉末 X 射线衍射（XRD）、热重（TG）和紫外可见吸收光谱对复合材料进行了表征。结果表明，Eu(3+)配合物通过偶联剂上的不同烷氧基（氨丙基三乙氧基硅烷（APTES）或氨丙基甲基二乙氧基硅烷（APMDES））接枝到凹凸棒石（或二氧化硅纳米粒子）的外表面上，接枝率不同。通过测定与基质相连的配合物的光物理行为和配位水分子，进一步证明了这些复合材料的结构。通过 APTES 连接的基于凹凸棒石的镧系元素复合材料可以被可见光激发，激发波长范围从紫外光到可见光很宽（最大波长为 398nm），荧光寿命长（503μs），量子产率高（48%），耐曝光性好。当在 37°C 下与 HeLa 细胞孵育时，在细胞膜上观察到基质-APTES-cpa-Eu(DBM)(3)的荧光。此外，我们目前的系统的低细胞毒性导致其在生物系统中的细胞成像中有潜在的应用。
