Yajun Wang

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Name: 王亚军; YaJun Wang
Organization: Fudan University , China
Department: Department of Chemistry
Title: Researcher/Professor(PhD)
Co-reporter:Yinghua Liu;Chao Deng;Deliang Yi;Xingdong Wang;Yi Tang
Nanoscale (2009-Present) 2017 vol. 9(Issue 41) pp:15901-15910
Publication Date(Web):2017/10/26
DOI:10.1039/C7NR06662G
Three-dimensional surface-enhanced Raman scattering (SERS) substrates are prepared via the in situ deposition of silver nanoparticles (AgNPs) on silica nanowire (SiO2 NW) assemblies, either in a free-standing membrane structure or as an optically transparent film supported on Scotch tape. The negatively charged surface of the SiO2 NW favors Ag+ ion enrichment around itself, with the ions forming densely deposited AgNPs on the NW after reducing agents are added to the solution. A SERS substrate with high sensitivity is achieved owing to abundant “hot spots” generated by the inter-AgNP gaps in the 3D geometry of the NW networks. The AgNP-deposited SiO2 NW membrane has a SERS enhancement factor of 2.9 × 108 and a detection limit of 10−9 M towards 4-mercaptopyridine probing and 10−8 M towards dithiocarbamate pesticide (i.e., thiram) probing. Moreover, the AgNP-deposited, Scotch tape-supported SiO2 NW film achieves non-invasive, direct detection of real-world surfaces due to its high sensitivity, high flexibility and optically transparent properties.
Co-reporter:Dr. Deliang Yi;Chenglong Xu;Ruidie Tang;Assoc. Xuehua Zhang; Frank Caruso; Yajun Wang
Angewandte Chemie International Edition 2016 Volume 55( Issue 29) pp:8375-8380
Publication Date(Web):
DOI:10.1002/anie.201603644

Abstract

We report the synthesis of highly flexible and mechanically robust hybrid silica nanowires (NWs) which can be used as novel building blocks to construct superhydrophobic functional materials with three-dimensional macroporous networks. The hybrid silica NWs, with an average diameter of 80 nm and tunable length of up to 12 μm, are prepared by anisotropic deposition of the hydrolyzed tetraethylorthosilicate in water/n-pentanol emulsions. A mechanistic investigation reveals that the trimethoxy(octadecyl)silane introduced to the water-oil interface in the synthesis plays key roles in stabilizing the water droplets to sub-100 nm and also growing a layer of octadecyl groups on the NW surface. This work opens a solution-based route for the one-pot preparation of monodisperse, hydrophobic silica NWs and represents an important step toward the bottom-up construction of 3D superhydrophobic materials and macroporous membranes.

Co-reporter:Dr. Deliang Yi;Chenglong Xu;Ruidie Tang;Assoc. Xuehua Zhang; Frank Caruso; Yajun Wang
Angewandte Chemie 2016 Volume 128( Issue 29) pp:8515-8520
Publication Date(Web):
DOI:10.1002/ange.201603644

Abstract

We report the synthesis of highly flexible and mechanically robust hybrid silica nanowires (NWs) which can be used as novel building blocks to construct superhydrophobic functional materials with three-dimensional macroporous networks. The hybrid silica NWs, with an average diameter of 80 nm and tunable length of up to 12 μm, are prepared by anisotropic deposition of the hydrolyzed tetraethylorthosilicate in water/n-pentanol emulsions. A mechanistic investigation reveals that the trimethoxy(octadecyl)silane introduced to the water-oil interface in the synthesis plays key roles in stabilizing the water droplets to sub-100 nm and also growing a layer of octadecyl groups on the NW surface. This work opens a solution-based route for the one-pot preparation of monodisperse, hydrophobic silica NWs and represents an important step toward the bottom-up construction of 3D superhydrophobic materials and macroporous membranes.

Co-reporter:Shanshan Bian, Jin Zheng, Xiaoling Tang, Deliang Yi, Yajun Wang, and Wuli Yang
Chemistry of Materials 2015 Volume 27(Issue 4) pp:1262
Publication Date(Web):January 23, 2015
DOI:10.1021/cm5042315
Monodisperse poly(vinylcaprolactam) (PVCL)-based capsules are prepared by precipitation polymerization of vinylcaprolactam (VCL) onto dimethyldiethoxysilane (DMDES) emulsion droplets and removal of the DMDES templates by ethanol. Polymer chains in the shells can be cross-linked during the polymerization by disulfide-containing cross-linker N,N′-bis(acryloyl) cystamine, which endows the capsules with an excellent redox-labile property. Versatility of this technique to prepare capsules with diverse components is demonstrated by the copolymerization of methacrylic acid (MAA) and VCL in the shell to prepare poly(vinylcaprolactam-co-methacrylic acid) (P(VCL-co-MAA)) capsules. The disulfide-bonded capsules can degrade efficiently into low molecular weight species (ca. 1200 Da) when the capsules are incubated with 10 mM glutathione (GSH) as the reducing agent. Delivery of the anticancer drug (doxorubicin, DOX) was also investigated in the P(VCL-co-MAA) capsules. The cumulative in vitro release of DOX-loaded capsules allows a relatively low DOX release at pH 7.4. However, a burst release (ca. 90% in 6 h) of DOX was observed in the presence of 10 mM GSH. Cell viability assays show that the P(VCL-co-MAA) capsules have negligible cytotoxicity to HeLa cancer cells. In comparison, DOX-loaded P(VCL-co-MAA) capsules cause significant cell death following internalization. The reported capsules represent a novel and versatile class of stimuli-responsive carriers for controlled drug delivery.
Luviskol Plus
Adriamycin
POLYMETHACRYLATE