[show abstract][hide abstract] ABSTRACT: We demonstrate a simple and efficient biosynthesis method to prepare easily harvested biocompatible cadmium telluride (CdTe)
quantum dots (QDs) with tunable fluorescence emission using yeast cells. Ultraviolet-visible (UV-vis) spectroscopy, photoluminescence
(PL) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) confirm that the CdTe QDs are formed
via an extracellular growth and subsequent endocytosis pathway and have size-tunable optical properties with fluorescence
emission from 490 to 560 nm and a cubic zinc blende structure with good crystallinity. In particular, the CdTe QDs with uniform
size (2-3.6 nm) are protein-capped, which makes them highly soluble in water, and in situ bio-imaging in yeast cells indicates that the biosynthesized QDs have good biocompatibility. This work provides an economic
and environmentally friendly approach to synthesize highly fluorescent biocompatible CdTe QDs for bio-imaging and bio-labeling
KeywordsCadmium telluride (CdTe) quantum dots-biosynthesis-biocompatible-
in situ bio-imaging
Nano Research 04/2012; 3(7):481-489. · 7.39 Impact Factor
[show abstract][hide abstract] ABSTRACT: We demonstrate an efficient synthesis of novel layered double hydroxide mesoporous silica core–shell nanostructures (LDH@mSiO2) that have a hexagonal MgAl-LDH nanoplate core and an ordered mesoporous silica shell with perpendicularly oriented channels via a surfactant-templating method. Transmission electron microscopy, X-ray diffraction and N2 sorption analyses confirmed that the obtained nanostructures have uniform accessible mesopores (2.2 nm), high surface area (430 m2 g−1), and large pore volume (0.22 cm3 g−1). Investigations of drug release and bio-imaging showed that this material has a slow release effect of ibuprofen and good biocompatibility. This work provides an economical approach to fabricate LDH@mSiO2 core–shell nanostructures, which may have great potential in broad drug delivery and hyperthermia therapy applications.
[show abstract][hide abstract] ABSTRACT: We demonstrate an efficient synthesis of novel layered double hydroxide mesoporous silica core-shell nanostructures (LDH@mSiO(2)) that have a hexagonal MgAl-LDH nanoplate core and an ordered mesoporous silica shell with perpendicularly oriented channels via a surfactant-templating method. Transmission electron microscopy, X-ray diffraction and N(2) sorption analyses confirmed that the obtained nanostructures have uniform accessible mesopores (∼2.2 nm), high surface area (∼430 m(2) g(-1)), and large pore volume (∼0.22 cm(3) g(-1)). Investigations of drug release and bio-imaging showed that this material has a slow release effect of ibuprofen and good biocompatibility. This work provides an economical approach to fabricate LDH@mSiO(2) core-shell nanostructures, which may have great potential in broad drug delivery and hyperthermia therapy applications.
[show abstract][hide abstract] ABSTRACT: Ordered mesoporous carbon-supported calcium oxide materials have been rationally synthesized for the first time. Large specific surface area, high content of nanosized calcium oxides can be easily obtained and tuned. The structure, porosity and the particle size evolution as a function of calcium content and carbonization temperature are extensively characterized and well correlated with their CO(2) sorption properties. The composite materials are of significance for CO(2) physisorption at ambient temperatures with high capacity and selectivity over N(2). Meanwhile, the nanocrystalline calcium oxides are highly active for CO(2) chemisorption, with tuneable and high CO(2) capacity at 200-500 °C. An almost complete initial conversion and fast reaction kinetics at a low temperature (450 °C) and low CO(2) pressure can be achieved within minutes. Cyclic stability is also substantially improved due to the confinement effect of the CaO nanoparticles within the mesopores. These materials would be suitable for CO(2) separation over a wide range of temperatures.
Physical Chemistry Chemical Physics 02/2011; 13(7):2495-503. · 3.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ordered mesoporous polymer-organosilica composites have been synthesized through a triconstituent co-assembly strategy. These composites have ordered 2-D hexagonal mesostructures (space group p6m) with uniform pore size (6.2-7.3 nm), suitable surface areas (619-794 m 2 g -1) and pore volumes (0.61-0.88 cm 3 g -1). With increasing BTSE (1,2-bis(triethoxysilyl)ethane) content, the surface area and pore volume reduce. The composites have homogeneous interpenetrating frameworks, in which both polymer and organosilica synergistically support the ordered mesostructure. The hybrid materials exhibit good adsorption capacities of benzene (up to 2.0 mmol g -1), suggesting their use as a potential adsorbent for removal of volatile organic compounds.
[show abstract][hide abstract] ABSTRACT: Large-pore phenyl-bridged periodic mesoporous organosilicas (PMOs) were facilely synthesized by evaporation-induced self-assembly of 1,4-bis(triethoxysily)benzene and triblock copolymer Pluronic F127 as a template under acid conditions combined with a mixed-solvothermal treatment. The ordered PMOs exhibit large uniform mesopores of approximately 9.9 nm in diameter after calcination at 350 degrees C in a nitrogen atmosphere. The mesoporous phenyl-bridged organosilica products have an ordered hexagonal mesostructure with space group p6mm. N(2) adsorption/desorption isotherms reveal imperfect mesopore channels with high surface areas (up to 1150 m(2)/g) and thick pore walls (up to 7.7 nm). The mesopores can be expanded with the decrease of acidity, as well as the increase of Pluronic F127 content. A mixed-solvothermal treatment in N,N-dimethylformamide (DMF) and water at 100 degrees C was first used to improve the periodicity of the mesopore walls, as well as increase the wall thickness. The composites exhibit efficient adsorption capacities (2.06 mmol g(-1)) for benzene, suggesting a potential adsorbent for removal of volatile organic compounds. The EISA approach combined with the mixed-solvothermal treatment provides important insights into the development of large-pore PMOs by using long-chain organosilanes, and further demonstrates the ability to fabricate materials with thick walls.
Journal of Colloid and Interface Science 03/2010; 346(2):429-35. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: Large-pore periodic mesoporous organosilica (PMO) hollow spheres with controllable pore size and high pore volume (2.5 cm3 g−1) were successfully synthesized at low-temperature (∼15 °C) by using the triblock copolymer Pluronic F127 as a template and 1,3,5-trimethylbenzene (TMB) as a swelling agent in the presence of inorganic salt (KCl). Transmission electron microscopy (TEM) measurements show that the PMO hollow spheres are uniform and well dispersed, and the composites have a large wall thickness. The influence of TMB, KCl, CTAB contents and media acidity on the mesostructure was systematically studied. The pore size (9.8–15.1 nm) of the hollow spheres can be gradually expanded by increasing TMB content together with a relatively high acidity. By controlling the content of CTAB, successive structural transformation from hollow sphere to wormlike mesostructure and eventually to ordered body-centered cubic (space group of Im-3m) mesostructure is observed. Our results reveal that the hydrophobicity of bis(triethoxysilyl)ethane (BTSE) and low-temperature approach contribute to the slow hydrolysis rate of silica precursors, which leads to weak interaction between individual TMB/F127 micelles and silicate oligomers. Furthermore, the salting-out effect of KCl may influence the swelling capacity of individual micelles as well as decrease the critical micelle concentration and critical micelle temperature, resulting in the formation of PMO hollow spheres from the assembly of individual TMB/F127 micelles with silicate oligomers. The composites exhibit efficient adsorption capacity (703 mg g−1) for toluene, suggesting they are a potentially useful adsorbent for removal of volatile organic compounds. The PMO hollow spheres allow biomolecules with large molecular weight to diffuse in, and show superior encapsulation capacity of bovine serum albumin (BSA) molecules (∼585 mg g−1) over other porous materials.
Microporous and Mesoporous Materials 01/2010; 132(3):543-551. · 3.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Well-ordered two-dimensional (2D) hexagonal periodic mesoporous organosilicas (PMOs) with a high content of disulfide groups have been prepared by a simple metal-ions-assisted amphiphilic surfactant templating process under a strong acidic condition. Long-chain organic bridge silane, bis(triethoxysilylpropyl)disulfide (BTSPDS) was used as a precursor which can be co-condensed with tetraethoxysilane (TEOS) to assemble with the triblock copolymer Pluronic P123 template and to construct the mesostructured organic–inorganic frameworks. The content of disulfide functional groups is up to 20% (BTSPDS molar content in the initial silane mixture) incorporated into the framework. The obtained ordered mesoporous DS-PMO materials have relatively high BET surface area (∼580 m2/g), large uniform pore size (up to 6.3 nm) and thick pore walls (thickness up to 7.1 nm), because of the long-chain disulfide bridges. The metal ions such as Zn2+ formed the four-coordination complex with two sulfides of BTSPDS and ethylene oxide moieties of P123 template, which could enhance the interaction between the “soft” long disulfide groups and P123 template, thus improving the mesostructural regularity correspondingly. The disulfide-bridged PMO materials exhibit excellent hydrothermal stability in boiling water for 5 days, probably due to the thick pore walls. SEM images show that after the hydrothermal treatment, the morphology of the ordered disulfide-bridged PMO materials is retained, as that of the wheat-like SBA-15. Excellent adsorption efficiency (∼716 mg/g) for Hg2+ ions is observed, suggesting a potential application in removal of heavy metal ions in wastewater.
[show abstract][hide abstract] ABSTRACT: Hydroxy-sodalite nanocrystals with organic functional groups (i.e., Si–(CH3)(CH2)3NH2, denoted Sod-N, or Si–CH3, denoted Sod-C) were synthesized by the direct transformation of organic-functionalized silicalite nanocrystals. The chemical structure of organic-functionalized sodalite nanocrystals was confirmed by 29Si MAS NMR spectroscopy. Gas sorption results showed that the sodalite nanocrystals contained uniform pore channels that were accessible to hydrogen, but inaccessible to nitrogen, as expected. The BET surface areas are calculated to be 22.8, 19.6 and 19.1m2/g for plain sodalite nanocrystals (Sod), Sod-N, and Sod-C, respectively; similarly, Sod-N and Sod-C exhibited slightly lower hydrogen adsorption than Sod. The dispersion of Sod-N and Sod-C in organic solvents was favored by the presence of organic functional groups. Therefore, the organic-functionalized sodalite nanocrystals prepared in this work may be very useful for fabricating zeolite nanostructures and sodalite-polymer nanocomposite membranes.
Microporous and Mesoporous Materials - MICROPOROUS MESOPOROUS MAT. 01/2007; 106(1):262-267.