Yunhua Wang

University of Queensland , Brisbane, Queensland, Australia

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Publications (25)90.35 Total impact

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    ABSTRACT: Periodic mesoporous organosilica microspheres (PMOMs) are designed with integrated structural features, including a cubic mesostructure, hydrophobic wall composition, a uniform pore size of ≈3 nm, and a spherical morphology in micrometers, all advantageous for size-selective and highly efficient enrichment of peptides from mixtures. Consequently, PMOMs can be used to capture peptides in a range of complex biological systems.
    Small 12/2011; · 7.82 Impact Factor
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    ABSTRACT: Small mesoporous silica nanoparticles (MSNs; ca. 37 nm in diameter) have a high loading capacity for a hydrophobic photosensitizer, SiPcCl(2) (82.6% in weight), and excellent endocytosis properties. As a result, the amount of SiPcCl(2) being delivered to cancer cells is increased by approximately two orders of magnitude compared to pure SiPcCl(2) at the same dosage, and the photodynamic therapy (PDT) efficiency is enhanced by over fourfold. Our method can be widely used to increase the dosage of hydrophobic anti-cancer drugs in cancer cells and therefore increase the cytotoxicity of the drugs.
    Chemistry - An Asian Journal 09/2011; 6(9):2332-8. · 4.57 Impact Factor
  • ChemPhysChem 02/2011; 12(2):278-81. · 3.35 Impact Factor
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    ABSTRACT: Periodic mesoporous organosilica (PMO) materials with large pores have been successfully synthesized using a combinational strategy by decreasing both the synthesis temperature and acidity. Herein, we use a tri-block copolymer EO106PO70EO106 [Pluronic F127, where EO is poly(ethylene oxide) and PO is poly(propylene oxide)] as the template, bis(trimethoxysilyl)ethane (BTME) as a silica source and 1,3,5-trimethylbenzene (TMB) as a pore expander. The PMO material synthesized in this approach has a face-centered cubic (fcc) structure. When the synthesis temperature is 0 °C and the acidity is 0.1 M HCl, the pore diameter of the PMO material reaches 33.6 nm, which is the largest among cubic PMO materials to our knowledge.
    Materials Letters. 01/2011; 65(1):21-23.
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    ABSTRACT: By using a nonionic block copolymer surfactant as the mesostructure directing agent, polystyrene (PS) colloidal particles or polyester (Terylene®) fibers as the macropore templates, mesoporous bioactive glass (MBG) materials with tunable macropores in a wide range (0.6–200μm) have been synthesized and their in vitro bioactivities have been studied. Macro-mesoporous bioactive glass (MMBG) materials obtained by using PS spherical templates have a uniform macropore size of ∼600nm, while MBG materials synthesized in the presence of terylene fibers have tubular channels (denoted TMBG) with diameters in the range of 8–200μm adjusted by the diameters of terylene fibers. Both MMBG and TMBG materials have uniform mesopores of ∼5nm in diameter. Similar to MBG materials, MMBG and TMBG materials have superior in vitro bioactivity compared to conventional bioactive glass. It is also shown that the size of macropore exerts influence on the hydroxycarbonate apatite (HCA) growth behavior within macropores. After soaking MMBG in simulated body fluid, HCA spheres gradually grow to sizes comparable to that of macro-pores after 24h. While in the case of TMBG, hollow HCA tubes form in the tubular channels of TMBG. It is expected MBG materials with tunable macropores and exceptional in vitro bioactivity may find potential applications in delivery of biological factors, tissue ingrowth, tissue regeneration and neovascularization.
    Microporous and Mesoporous Materials - MICROPOROUS MESOPOROUS MAT. 01/2011; 143(1):157-165.
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    ABSTRACT: The structure of an unconventional mesoporous material, formed by the packing of silica coated spherical micelles as hard spheres, has been uniquely determined through a series of advanced characterization techniques. The synchrotron-based small-angle X-ray scattering (SAXS) analysis confirms that the bulk material assembled via the hard sphere packing (HSP) route exhibits a strong 200 reflection and a relatively weaker 111 reflection, which is the first example in all reported mesostructured materials with the same symmetry. At the morphological macroscale, high-resolution scanning electron microscopy (SEM) images directly show that the hexagonal platelike micrometer-sized particles consist of nanospheres (20 nm in diameters) in a close packing mode. The intrinsic pore structure of calcined HSP material has been reconstructed using both electron crystallography (EC) and electron tomography (ET) techniques, which can be simply viewed as a face-centered cubic (fcc) packing of monodispersed hollow silica nanospheres. The EC technique provides a three-dimensional visualization of the pore organization and demonstrates the existence and crystallographic positions of the cagelike mesopores, octahedral and tetrahedral cavities. The ET method directly and accurately determines the sizes of the mesopores and octahedral cavity and offers nanometer-scale structural information at any given local area, which cannot be obtained by conventional transmission electron microscopy (TEM). To our knowledge, this is the first time that the EC and ET techniques are simultaneously employed and provide complementary information for the mesostructure determination. More importantly, the structural details collected from the synchrotron SAXS, high resolution SEM, EC and ET techniques are consistent and support the HSP mechanism, different from the well-understood liquid crystal templating or cooperative self-assembly pathways. The complex pore structure and the existence of octahedral and tetrahedral cavities are responsible for the unusual indexation of the SAXS, which is further validated by the structural simulation. Our work provides both a comparative and comprehensive case study to show the strength and limitation of individual techniques and demonstrates the need for the careful characterization of novel structures by a selection of complementary, state-of-the-art methods which provide selective structural information at different length scales. 2010 American Chemical Society.
    01/2011;
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    ABSTRACT: Hierarchical Cu4V2.15O9.38 micro-/nanostructures have been prepared by a facile "forced hydrolysis" method, from an aqueous peroxovanadate and cupric nitrate solution in the presence of urea. The hierarchical architectures with diameters of 10-20 µm are assembled from flexible nanosheets and rigid nanoplates with widths of 2-4 µm and lengths of 5-10 µm in a radiative way. The preliminary electrochemical properties of Cu4V2.15O9.38 have been investigated for the first time and correlated with its structure. This material delivers a large discharge capacity of 471 mA h g(-1) above 1.5 V, thus making it an interesting electrode material for primary lithium ion batteries used in implantable cardioverter defibrillators.
    Nanoscale 12/2010; 3(3):999-1003. · 6.73 Impact Factor
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    ABSTRACT: A series of MoxW1−xO3·0.33H2O (x = 0, 0.25, 0.50, 0.75) micro/nanostructures and α-MoO3 nanobelts have been prepared by a facile hydrothermal treatment method starting from aqueous peroxo-polytungstic acid and peroxo-molybdic acid solutions. The WO3·0.33H2O lattice can be substituted with up to 75% Mo without structural alterations of the orthorhombic host structure. With the increase of the Mo content (x) from 0 to 0.75, the band gap of the as-prepared MoxW1−xO3·0.33H2O micro/nanostructures is narrowed from 3.25 to 2.77 eV. The increased M5+ (M = Mo and W) fraction and thus enhanced intervalency-transition are responsible for the narrowing of the band gap.
    The Journal of Physical Chemistry C. 11/2010; 114(49).
  • 10/2010;
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    ABSTRACT: The analysis of peptides by the mass spectrometry (MS) technique is important in modern life science. The enrichment of peptides can increase the detection efficiency and is sometimes indispensable for collecting the information on proteins with low-abundance. Herein, we first report that functionalized periodic mesoporous organosilica (PMO) materials have a superior peptide enrichment property. It is demonstrated that the PMO materials with an organo-bridged (-CH(2)-) hybrid wall composition display a highly enhanced peptide enrichment ability compared to the pure silica material (SBA-15) with similar mesostructured parameters and morphology. More importantly, by surface modification of PMO with amino groups (denoted NH(2)-PMO), PMO and NH(2)-PMO with opposite charged surfaces (-25.2 and +39.0 mV, respectively) show selective affinities for positively and negatively charged peptides, respectively. By directly adding PMO, NH(2)-PMO as well as pure silica materials to the peptides solution with a low concentration (1-2 fmol/microL), 36 and 28 peptides can be detected from the BSA digestion in the presence of PMO and NH(2)-PMO, respectively, while only 6 and 4 are monitored in the case of SBA-15 enrichment and from solution without enrichment, respectively. Moreover, 69.4% (25 of 36) of enriched peptides by PMO have pI > or = 6 and 80% (21 of 28) of enriched peptides by NH(2)-PMO possess pI < or = 6. Combining the results from the NH(2)-PMO and PMO enrichment together, 51 peptides can be identified with a MOWSE score of 333. It is also noted that similar conclusions can also be obtained from the peptides solution originated from other proteins. This might be an important contribution to the understanding of the interaction between peptides and porous hosts, and the proposed method is promising for the development of both material science and biotechnology.
    Langmuir 05/2010; 26(10):7444-50. · 4.38 Impact Factor
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    ABSTRACT: A direct method to determine the pitch and chirality of complicated hierarchical helical mesostructures is presented by using the state-of-the-art electron tomography technique.
    Chemical Communications 03/2010; 46(10):1688-90. · 6.38 Impact Factor
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    ABSTRACT: Urchin-like CdWO4 microspheres with hollow interiors have been successfully synthesized by a facile template free hydrothermal treatment method. The urchin-like CdWO4 hollow spheres are composed of radiatively assembled single-crystalline CdWO4 nanorods with lengths of several hundred nm and widths of 25–80 nm. The samples exhibit a blue-green emission in the range of 450–500 nm with the emission peak centered around 470 nm when excited at 293 nm. The effects of the preparation conditions such as the hydrothermal synthesis temperature, hydrothermal synthesis time, and the dosage of urea on the crystalline phase as well as morphology of final products have been systematically investigated. The successful synthesis of CdWO4 with a uniform urchin-like morphology relies on not only the choice of peroxo-polytungstic acid precursor, but also a controlled pH adjustment with the help of urea, both of which contribute to a homogenous nucleation and crystal growth process. It is also found that increasing the synthesis temperature, time and dosage of urea will enhance the photoluminescence (PL) emission of resultant materials. Our contribution provides a simple approach to synthesize CdWO4 materials with hierarchical architectures and potential applications as detectors in X-ray devices.
    CrystEngComm 01/2010; · 3.88 Impact Factor
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    ABSTRACT: Various siliceous nanostructures have been successfully synthesized through the co-organization of organic molecules and inorganic silica source under mild pH conditions (pH approximately 5). A biodegradable block copolymer P123 [EO20PO70EO20, EO is poly (ethylene oxide), PO is poly (propylene oxide)] is employed as a marcomolecular template and Na2SiO39H2O as a silica source. By changing the concentrations of the reactants and/or reaction temperature, siliceous multilamellar vesicles, unilamellar nano-foams and multilamellar vesicles with sponge-like walls have been obtained. Our work provides a convenient and bioinspired route to obtain siliceous nanostructured materials with adjustable and multi-level pore structures as well as rich morphologies, which is important to understand the biomineralization mechanism. Such artificial silica nanoporous materials may find potential applications in catalysis, separations, electronics, and photonics, etc.
    Journal of Nanoscience and Nanotechnology 01/2010; 10(1):612-5. · 1.15 Impact Factor
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    ABSTRACT: The cooperative self-assembly of organic-inorganic siliceous composite structures has been studied from the aspect of inorganic precursors. We reveal that the vesicular or mesostructured materials can be obtained selectively by just changing the silica sources in one templating system. For poly(ethylene oxide)-type block copolymers with either poly (propylene oxide) or poly(butylene oxide) as the hydrophobic moieties, when the other synthesis parameters are exactly the same, the use of tetramethyl orthosilicate (TMOS) as a silica source gives rise to highly ordered mesostructures, while the use of tetraethyl orthosilicate (TEOS) leads to vesicles or foams. The attenuated total reflection Fourier transform infrared (ATR-FTIR) technique is used to monitor the silicate species derived from the hydrolysis and condensation of TMOS and TEOS as a function of the reaction time. On the basis of the ATR-FTIR results, we propose a "differentiating effect" at relatively high pH (4.7) to interpret the influence of different silica sources on the selforganized composite structures. For comparison, a "leveling effect" at relatively low pH (strong acidic conditions) is revealed to explain that both TMOS and TEOS lead to the same mesostructures. Our contribution provides a feasible and designable method to synthesize from conventional ordered mesostructures to novel vesicular structures, which are significant for their future practical applications. 2010 Materials Research Society.
    Journal of Materials Research 01/2010; · 1.82 Impact Factor
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    ABSTRACT: Helical conformation exists universally at different length scales. We present a new model to explain the energetics of a helical structure with ordered mesopores and successfully predict their equilibrium state. The formation of the helical structure, which is composed of twisted and hexagonally arrayed one-dimensional pore channels, should be understood at the macromorphology level through the competition between surface free energy reduction and torsion strain energy increase. Our model is established by first reverting a helical rod with experimentally defined parameters to a conjectured straight rod without intrinsic pore channel twisting, and then quantitatively calculating the variation of two competitive energies as a function of twist angle in the torsion process starting from the reverted straight rod. Through our model, a free energy curve is achieved, so that the equilibrium state and the helical structural parameters can be predicted, which are in good agreement with experimental results for helical rods synthesized by different surfactant templates. Moreover, our model can be successfully applied to explain the pitch-radius relationships in previous observations. Our achievement provides unique and fundamental understandings for the spontaneous mesoscopic helix formation, which are different from the microscopic helical structures such as DNA chains.
    The Journal of Physical Chemistry B 12/2009; 113(50):16178-83. · 3.61 Impact Factor
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    ABSTRACT: An intriguing evolution from a simple internal helix to a hierarchical helical (HH) mesostructure with both internal and external helices or a complicated screwlike and concentric circular (CC) mesostructure is successfully observed. The complicated helical structures are determined by TEM studies and 3D electron tomography. We demonstrate a topological helix-coil transition between the internal and external helices to reveal the origin of the HH mesostructure and the relationship between the straight helical and HH rods. Moreover, the boundary condition of the helix-coil transition is clarified to explain in detail the formation of complex helical structures, such as the screwlike mesostructure. It is proposed that the final structural characteristics are determined exactly by the balance between the decrease in the surface free energy and the maintenance of the hexagonal packing in one individual rod, which explains the formation of unusual CC, HH, and screwlike morphologies in one pot. Our success has opened new opportunities in the characterization of complex porous architectures, thus paving a way to remarkable advances in the fields of synthesis, understanding, and application of novel porous materials.
    Chemistry 12/2009; 16(5):1629-37. · 5.93 Impact Factor
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    ABSTRACT: The synthesis of ultrasmall, well-dispersed, hollow siliceous spheres (HSSs) by using a block copolymer as the template and tetraethoxysilane as a silica source under acidic conditions is reported. After removing the surfactant core of as-synthesized, spherical, silica-coated block-copolymer micelles, HSSs with a uniform particle size of 24.7 nm, a cavity diameter of 11.7 nm, and a wall thickness of 6.5 nm are obtained. It is shown that by surface functionalization of HSSs with methyl groups during synthesis, HSSs can be further dispersed in solvents such as water or ethanol to form a stable sol. Moreover, the hollow cavities are accessible for further loading of functional components. In addition, it is demonstrated that HSSs possess superior endocytosis properties for HeLa cells compared to those of conventional mesoporous silica nanoparticles. A feasible and designable strategy for synthesizing novel well-dispersed hollow structures with ultrasmall diameters instead of conventional ordered mesostructures is provided. It is expected that HSSs may find broad applications in bionanotechnology, such as drug carriers, cell imaging, and targeted therapy.
    Small 11/2009; 6(2):276-82. · 7.82 Impact Factor
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    ABSTRACT: This study systematically investigates periodic mesoporous organosilicas (PMOs) with controlled helical and concentric circular (CC) pore architectures prepared through a basic-catalyzed sol-gel process by using an achiral cationic surfactant trimethyloctadecylammonium bromide (C(18)TAB) as a structure-directing agent, perfluorooctanoic acid (PFOA) as an additive, and 1,2-bis(triethoxysilyl)ethane (BTEE) as a hybrid silica precursor. By increasing the weight ratio of PFOA/C(18)TAB, a pore architecture transition of PMO materials from hexagonal-arrayed, straight longitudinal channels to helical and CC mesostructures is achieved; such a transition has not been observed before in PMO materials. Our discovery is helpful in understanding the supramolecular cooperative assembly of hybrid materials and their structural and morphological evolution, which are important in the future applications of PMO materials.
    Chemistry 09/2009; 15(42):11319-25. · 5.93 Impact Factor
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    ABSTRACT: A novel nanopore based digestion strategy has been developed by directly adding a macroporous material as catalyst to the conventional in-solution reaction system. Without increasing the enzyme or protein concentrations, this simple digestion approach exhibits high proteolysis efficiency and selectivity due to the in situ fast adsorption of both enzymes and proteins from bulk solution into the macropores of the catalysts, where the target substrates and enzymes are greatly concentrated and confined in the nanospace to realize a quick digestion. Based on the electrostatic interaction matching between the biomolecules and catalysts, selective extraction and digestion of proteins with different isoelectric points can be achieved by adjusting the surface charge of the catalysts. This nanoporous reaction system has been successfully applied to the analysis of a complex biological sample, where 293 proteins are identified, while only 100 proteins are obtained by the standard overnight in-solution digestion. The present nanospace confined digestion strategy will lead to promising advances not only in proteomics but also in other applications where enzymatic reactions are involved.
    Analytical Chemistry 08/2009; 81(14):5749-56. · 5.70 Impact Factor
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    ABSTRACT: Enriching peptides: Novel TiO(2)-modified macroporous materials (Ti-MOSF, see figure) have been synthesized with high surface area, large pore volume, and functional surfaces that are rich in coordinatively unsaturated Ti(IV) species, which can be applied in the specific extraction of phosphopeptides and which show a preferential capture of multi-phosphorylated peptides with low detection limits and high selectivity.
    Chemistry 03/2009; 15(11):2504-8. · 5.93 Impact Factor