A novel mesoporous nanosphere functionalized with 3-(aminopropyl)triethoxysilane (APTES) and 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline (5-Br-Tip) was synthesized (denoted as Tip-MSS). With the coordinating function of the 5-Br-Tip to lanthanide (Ln) ions, for the first time, LnL3(5-Br-Tip) complexes were linked to the mesoporous nanospheres. The derived materials, named Ln-Tip-MSS (Ln = Eu, Tb, Sm, Nd, Yb), were characterized by Fourier-transform infrared (FT-IR) spectroscopy, TEM, XRD (wide-angle and small-angle), N2 adsorption/desorption analysis, and fluorescence spectroscopy. Upon excitation in the ligand absorption, the Ln-Tip-MSS nanomaterials show characteristic visible (Eu, Tb, Sm) and NIR (Sm, Nd, Yb) luminescence (multicolor emission covered from 450 nm to 1400 nm spectral region). Of importance is that, with low cytotoxicity and good biocompatibility given by the methyl thiazolyl tetrazolium (MTT) assay, the Eu-Tip-MSS was successfully applied to cell imaging in vitro based on the Eu3+ luminescence (under 405 nm excitation).
Yuanyuan Zheng,Xiaoming Zhang,Yi Yao,Xiaohong Chen,Qihua Yang
Ultra-small Au nanoparticles (<2 nm) supported on hollow silica nanospheres were successfully fabricated with the aid of chemical modification (–SH groups) or through simple immersion method, leading to supported catalysts Au/SH-HNS and Au/HNS. The resulting solid catalysts showed good thermal stability and the small particle sizes could be remained even at high temperature of 350 °C. Such catalysts were catalytically active in the oxidation of styrene using O2 as oxidant under 1 atm pressure. The catalytic results showed that the activity strongly depends on the Au loading amount, and the loading of 4–5 wt% led to the highest activity. Significant rate enhancement was observed with gold nanoparticles supported on pure silica in comparison with thiol modified silica nanospheres, suggesting the negative effects of thiol groups. The solid catalyst could be reused at least 8 reaction cycles without significant decrease in activity and selectivity. This study not only supplies an active, recoverable catalyst for the green transformation of styrene, but also demonstrates that the hollow silica nanosphere material has a superior ability in stabilizing metal nanoparticles against growth.
Zhijia Zhang,Xiaole Zhao,Yingchun Su,Defeng Xing,Xiaojun Han
We demonstrate that antibacterial agent N , N′ -[(4, 5-dihydroxy-1, 2-phenylene)bis(methylene)]bisacrylamide (OHABA) can be assembled on the surface of vinyl organosilicon nanospheres (VOSNs) by atom transfer radical polymerization (ATRP). Chemically cross-linked vinyl organosilicon cores were facilely fabricated by sol-gel method as support, which densely grafted poly-OHABA (POHABA) as shells. Antibacterial assessment test results revealed that POHABA-based core@shell structure displayed high antibacterial performance, long-term stability, and kept broad-spectrum antibacterial effect of against Gram-negative and Gram-positive bacteria.
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