Wenru Zhao

Facile Synthesis of Monodisperse Superparamagnetic Fe3O4 Core@hybrid@Au Shell Nanocomposite for Bimodal Imaging and Photothermal Therapy

A simple seed-mediated growth route is developed to fabricate monodisperse, uniform superparamagnetic Fe(3)O(4) core/gold shell structured nanocomposites with tunable sizes and optical properties, in which gold seed formation and attachment onto the core surface via S-Au covalent bonding proceeds almost simultaneously in the one-pot synthesis. The as-prepared nanocomposite is demonstrated to have a great potential for magnetic resonance imaging (MRI)-guided, focused photothermal tumor therapy under near-IR laser radiation.

Fe3O4 core/layered double hydroxide shell nanocomposite: versatile magnetic matrix for anionic functional materials.

Recently, microor nanospheres with magnetic cores and functional shell structures have received much attention because of their potential applications in catalysis, drug storage/release, selective separation, chromatography, and chemical or biosensors. Until now, different shell frameworks have been developed to pursue these aims. Some groups fabricated mesoporous silica shell to load metal oxides and fluorescence imaging materials and used them in catalysis and drug storage/release systems. Diat et al. discovered that monodisperse and compactly packed onion phases could be obtained in concentrated solutions of surfactants under controlled mechanical shear. Their applications as carriers for drug delivery or nanoreactors for the synthesis of metal nanoparticles have been explored. Wang et al. used dimercaptosuccinimide acid modified Fe2O3 nanoparticles and combined them with CdSe/ZnS quantum dots (QDs) to prepare water soluble magnetic luminescent composites in an organic/water two-phase mixture. Bawendi and co-workers simultaneously encapsulated both CdSe QDs and g-Fe2O3 in silica microspheres to prepare a magnetic luminescent composite. All these exploitations of the shell structure greatly expand the realm of applications of magnetic core/ shell materials. However, in all of these applications, the method for loading functional materials into the shell structure is largely different from each other, even for the same shell structures. Is there a facile and versatile approach to synthesize magnetic core/functional shell structures? Layered double hydroxides (LDHs), consisting of stacked brucite-type octahedral layers with anions and water molecules occupying the interlayer space, are currently attracting intense research interest. Recently, we succeeded in total delamination of LDH crystals in nitrate form upon treatment with formamide, and used this product as a building block to fabricate the LDH hollow shell structure. The LDH structure collapsed upon heat treatment at about 500 8C to yield mixed oxides of constituent elements, which underwent restoration of the LDH structure in the presence of water and anions. This so-called memory effect property of LDHs has been employed as an effective synthetic route for inserting various functional inorganic and organic anions into LDHs galleries. 17] Herein, we report the synthesis and characterization of a Fe3O4 core/oxide shell nanocomposite decomposed from a layered double hydroxide, which combines both versatile anion loading capability and high separation efficiency, making it an ideal support for recoverable anionic functional materials. As shown in Figure 1, the center of the structure is a

Fabrication of uniform hollow mesoporous silica spheres and ellipsoids of tunable size through a facile hard-templating route

A facile hard-templating route has been successfully developed to fabricate uniform hollow mesoporous silica spheres and ellipsoids by using hematite as hard template. The outer diameter of the spherical mesoporous silica particles can be well adjusted in a sub-micrometric range (typically around 100–200nm) by selecting suitable hematite particles as core templates. The thickness of the mesoporous shell can be tuned independently at around 10nm by tailoring the amount of tetraethoxysilane and n-octadecyltrimethoxysilane mixture. Ellipsoidal hollow mesoporous silica particles are prepared as well for the first time when spindle shaped hematite particles are employed as core templates. In addition, these hollow mesoporous particles manifest high drug storage capacity (726 mg ibuprofen per gram) mainly and physically in the core part, hence justifying their promising applications as nanocarriers in drug delivery.

Effective adsorption and enhanced removal of organophosphorus pesticides from aqueous solution by Zr-based MOFs of UiO-67.

Though many efforts have been devoted to the adsorptive removal of hazardous materials of organophosphorus pesticides (OPs), it is still highly desirable to develop novel adsorbents with high adsorption capacities. In the current work, the removal of two representative OPs, glyphosate (GP) and glufosinate (GF), was investigated by the exceptionally stable Zr-based MOFs of UiO-67. The abundant Zr-OH groups, resulting from the missing-linker induced terminal hydroxyl groups and the inherent bridging ones in Zr-O clusters of UiO-67 particles, served as natural anchorages for efficient GP and GF capture in relation with their high affinity toward phosphoric groups in OPs. The correlation between the most significant parameters such as contact time, OPs concentration, adsorbent dose, pH, as well as ionic strength with the adsorption capacities was optimized, and the effects of these parameters on the removal efficiency of GP and GF from the polluted aqueous solution were investigated. The adsorption of GP on UiO-67 was faster than that of GF, and a pseudo-second-order rate equation effectively described the uptake kinetics. The Langmuir model exhibited a better fit to adsorption isotherm than the Freundlich model. Thanks to the strong affinity and adequate pore size, the adsorption capacities in UiO-67 approached as high as 3.18 mmol (537 mg) g(-1) for GP and 1.98 mmol (360 mg) g(-1) for GF, which were much higher than those of many other reported adsorbents. The excellent adsorption characteristics of the current adsorbents toward OPs were preserved in a wide pH window and high concentration of the background electrolytes. These prefigured the promising potentials of UiO-67 as novel adsorbent for the efficient removal of OPs from aqueous solution.

A glucose-responsive controlled release of insulin system based on enzyme multilayers-coated mesoporous silica particles

A novel glucose-responsive controlled release of insulin system is constructed through coating enzyme multilayers on mesoporous silica particles (MSPs). The MSPs serve as the drug reservoir, and the enzyme multilayers cross-linked with glutaraldehyde act as a valve to control the release of insulin in response to the external glucose level.

Facile Synthesis of Magnetite/Perfluorocarbon Co‐Loaded Organic/Inorganic Hybrid Vesicles for Dual‐Modality Ultrasound/Magnetic Resonance Imaging and Imaging‐Guided High‐Intensity Focused Ultrasound Ablation

Multifunctional organic/inorganic hybrid nanovesicles, fabricated by a facile self-assembly/sol-gel approach, display a unique morphology (figure) and satisfactory stability under physiological conditions. By co-encapsulation of superparamagnetic magnetite nanoparticles and a liquid perfluorocarbon, the nanovesicles can be used not only as a dual-modality ultrasound/magnetic resonance contrast agent for accurate cancer diagnosis and monitoring, but also as a therapeutic enhancement agent for effective high-intensity focused ultrasound (HIFU) ablation.

Promotion effects of SiO2 or/and Al2O3 doped CeO2/TiO2 catalysts for selective catalytic reduction of NO by NH3

A series of the CeO2-based catalysts loaded on TiO2, TiO2-SiO2, TiO2-Al2O3, and TiO2-SiO2-Al2O3 supports were prepared by incipient impregnation method for the selective catalytic reduction (SCR) of NO by NH3 in the presence of oxygen. The SCR activities of the catalysts with different supports increases in the order of Ce/TiO2 < Ce/TiO2-20SiO2 ≈ Ce/TiO2-3.5Al2O3 < Ce/TiO2-20SiO2-3.5Al2O3. The Ce/TiO2-20SiO2-3.5Al2O3 catalyst showed 100% NO conversion in the temperature range of 250-425°C and 100% N2 selectivity in the whole temperature range. The catalytic activity of Ce/TiO2-20SiO2-3.5Al2O3 exhibited good stability and strong resistance to SO2 and H2O poisoning. The co-introduction of SiO2 and Al2O3 into TiO2 could increase the amount of chemisorbed oxygen and Lewis acid sites on the surface of catalyst, which should be responsible for the excellent SCR activity.

Sub-150 nm mesoporous silica nanoparticles with tunable pore sizes and well-ordered mesostructure for protein encapsulation

Despite their great potentials as biomacromolecues delivery vehicles, there are few, if any, reports on mesoporous silica nanoparticles (MSNs) simultaneously integrated with the merits of large pore size, small particle diameters and well-ordered mesostructure. Here, we designed a facile strategy for the synthesis of monodispersed MSNs using cationic surfactants (CSs) as templating agents, neutral amine of N,N-dimethylhexadecylamine (DMHA) as a pore size mediator and tri-block copolymer of F127 (EO106PO70EO106) as a particle growth inhibitor/dispersant. The obtained colloidal nanoparticles exhibited a highly ordered mesostructure and tunable pore diameter up to 4.6 nm (BJH) and monodispersed particle sizes less than 150 nm. A model protein of cytochrome c (CytC) was exemplified to be accommodated in the resultant MSNs and its loading amount was correlated with their pore size. The efficient cancer cellular uptake of the large-pore MSNs prefigured their potentials as intracellular delivery vehicles for membrane-impermeable proteins.

Controlled synthesis of multilayered gold nanoshells for enhanced photothermal therapy and SERS detection.

It can be streamlined: A facile and controllable approach for the fabrication of core/shell-structured multilayer gold nanoshells with uniform nanosize, monodispersity, and tunable plasmonic properties has been successfully developed by utilizing an organosilica layer as the dielectric spacer layer.

A Simple Route to Prepare Monodisperse Au NP-Decorated, Dye-doped, Superparamagnetic Nanocomposites for Optical, MR, and CT Trimodal Imaging

Monodisperse and uniform AuNP-decorated, dye-doped, superparamagnetic nanocomposites (Fe3 O4 @dye-hybrid@Au) are fabricated by using a simple method in which the Au NP formation and their attachment onto the core surface via S-Au covalent bonds proceeds almost simultaneously in a one-pot synthesis. The as-synthesized nanocomposites can simultaneously enhance the contrast effects for MR, CT, and cellular-sensitive optical imaging.