Titania nanotube (NT) arrays have been widely used as cell-supporting matrices. However, cells are always seeded on the porous surface of the NT array and have very limited interactions with each individual NT in the array. In this study, titania hollow microtubes (HMTs) were synthesized via a gelatin-template sol-gel route and then utilized as free-standing cell-supporting matrices for the first time. The resultant titania HMTs were studied by field emission scanning electron microscopy, energy-dispersed spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. Each HMT was composed of rutile-type titania nanoparticles with diameters of 50–100 nm and a diameter of 50–100 µm. The results from a leaching liquor assay demonstrated good biocompatibility of titania HMTs. Each HMT has been demonstrated to independently support the adhesion and proliferation of osteoblast MC3T3-E1 cells. For comparison, titania NT arrays, not independent titania NT, only supported the adhesion of cells on their porous surface. Thus, the resultant titania HMTs are applicable to free-standing and biocompatible cell-supporting matrices.
Jian Fang,Xi Chen,Rong-Pu Xiao,Jing-Jing Xue,Ji-Ming Song
Metal-organic framework (MOF) can be used as sacrificial templates for preparing metal oxides with unique hollow structures. The heterojunction formed between two metal oxides is conducive to improvement of gas sensor performance. Herein, MOF compounds containing In with hexagonal prism morphology were synthesized first, and then annealed to obtain uniform hexagonal In 2 O 3 hollow microtubes. Subsequently, the surface of In 2 O 3 hollow microtubes was decorated by the Pr-doped SnO 2 nanoparticles (NPs) in solution under stirring, and the Pr-SnO 2 /In 2 O 3 composite was obtained. Various characterization techniques confirmed the successful preparation of the Pr-SnO 2 NPs/In 2 O 3 composite. The specific surface area of the composite reached 72.07 m 2 /g. The sensing performance of the SnO 2 , Pr-SnO 2 , In 2 O 3 , SnO 2 /In 2 O 3 , and Pr-SnO 2 /In 2 O 3 sensors to ethanol gas were systematically investigated. Among these sensors, at the optimal working temperature, the Pr-SnO 2 /In 2 O 3 sensor displayed the best sensing performance with a response value of 75 towards 50 ppm ethanol, and further exhibited good linearity coefficient, selectivity, reproducibility, and long-term stability.
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