Co-reporter:Liping Wang;Ming Wang;Yunli Wang;Yiran Shao
CrystEngComm (1999-Present) 2017 vol. 19(Issue 48) pp:7298-7306
Publication Date(Web):2017/12/12
DOI:10.1039/C7CE01871A
Fluorine plays an important role in dental protection and formation of enamel materials, however the intrinsic effect of fluorine on the formation mechanism of fluoridated hydroxyapatite still needs to be known. In this work, pure fluoridated hydroxyapatite (FHA) with a hierarchical architecture was produced by a simple one-pot method using CaF2, Ca(OH)2 and Ca(H2PO4)2·H2O. It was found that the hierarchical fluoridated hydroxyapatite showed a unique orientation structure and different phase transformation mechanism compared with hydroxyapatite (HA). In the phase transition process from DCPD (CaHPO4·2H2O, brushite) to DCPA (CaHPO4, monetite), and then to FHA, hierarchical FHA was formed with the c-axis-oriented nanowires perpendicular to the planes of DCPA plates. More importantly, the crystal orientation relationship between FHA and DCPA was found for the first time to be FHA [010]//DCPA [001] and FHA (001)//DCPA (010), which is quite different from the crystal orientation relationship of HA [10]//DCPA [110] and HA (12)//DCPA (112). It was found that the phase transition process from (100)DCPA to (100)FHA was occurred with a good crystal lattice match. F− on (100)FHA had a small ionic radius and high electronegativity, decreased the crystal lattices of (100)FHA and might enhance their negativity and reactivity. This result may help better understand the effect of fluorine on the crystal growth process of natural enamel and the preparation of pure FHA with a hierarchical architecture is informative for the synthesis of enamel-like biomaterials.
Co-reporter:Jingke Fu
Journal of Materials Chemistry B 2017 vol. 5(Issue 5) pp:996-1004
Publication Date(Web):2017/02/01
DOI:10.1039/C6TB02820A
Conventional chemotherapy uses potent toxic drugs to destroy cancer cells and always causes severe systemic toxicity in patients. In this respect, a smart and pH-switched prodrug/procatalyst co-delivery nanosystem is developed which is non-toxic toward normal cells and is inert during its delivery in the vasculature, while responsively functions in acidic lysosomes inside cancer cells. Synthetically, non-toxic artemisinin (ART) was used as the prodrug and loaded into the inner space of hollow mesoporous silica (HMS) nanoparticles (NPs). Subsequently, Fe3O4 NPs were efficiently capped onto pore outlets of HMS via acid labile acetal linkers (ART@HMS-Fe3O4). ART@HMS-Fe3O4 was stable under neutral conditions (pH 7.4) with almost no leakage of ART. Upon exposure to the acidic lysosomal compartment (pH 3.8–5.0) in cells, the acetal linkers were hydrolyzed which led to sustained release of both ART and Fe3O4 NPs. Under the activation of the lysosomal environment, the liberated Fe3O4 NPs were metabolized to free iron ions and catalyzed the generation of high amounts of free radicals from the released ART in cells. In vitro cytotoxicity assay revealed excellent anticancer efficacy of this ART/Fe3O4 co-delivery nanosystem. The Fe3O4 NPs acted both as gatekeepers and procatalysts which inhibited ART from leakage during their delivery, while released ART and activated chain reactions to form free radicals in acidic lysosomes inside cancer cells. We visualize that this lysosomal environment-responsive ART@HMS-Fe3O4 nanosystem could serve as an efficient and desirable chemotherapeutic nanosystem for cancer therapy.
Co-reporter:Yangyang Xing;Chengkang Chang
Journal of Materials Science: Materials in Electronics 2017 Volume 28( Issue 13) pp:9464-9470
Publication Date(Web):20 March 2017
DOI:10.1007/s10854-017-6689-9
Eu2+-doped β-Sialon phosphors with a composition of EuxSi5Al1−xOz+xN8−z−x (x = 0.05, 0.06, 0.07) were synthesized in a new synthetic route using novel raw materials, such as nano-silicon dioxide (SiO2), nano-carbon (C), and aluminum (Al). This is different from the prevailing method using Si3N4, AlN, and Al2O3 to obtain β-Sialon phosphors. Compared with the conventional method, lower cost raw materials, simpler pretreatment and a relatively shorter reaction time are achieved. The phosphors show a high purity. All the phosphors exhibit green emission under ultra violet (UV) radiation. A broad band of excitation spectra implies the promising application in UV ray based green light-emitting diode (LED). Chromaticity coordinates of the β-Sialon: Eu2+ phosphors demonstrate that it is accessible to obtain different green emissions from single phase of Eu2+-doped β-Sialon through adjusting Eu2O3 concentration. Furthermore, the EuxSi5Al1−xO1 + xN7 − x (x = 0.05) shows a better thermal stability than the commercial green-emitting silicate phosphor. These results indicate a promising prospect for this efficient and economic route in preparing β-Sialon: Eu2+ phosphors, and the phosphors are a highly promising candidate for LED applications.
Co-reporter:Liqiang Lu, Yingchun Zhu, Chao Shi, Yutao T. Pei
Carbon 2016 Volume 109() pp:373-383
Publication Date(Web):November 2016
DOI:10.1016/j.carbon.2016.08.023
Graphene quantum dots (GQDs) exhibit unique physical and chemical properties due to their quantum confinements, edge effects and defect contents. Synthesis of GQDs with controlled defect content is an important issue for various applications. In this paper, an environmental friendly, fast and industrial promising method for synthesizing GQDs in large scale is reported via an ultrasonic-assisted liquid-phase exfoliation technique. The production yield of GQDs in N-methyl-2-pyrrolidone (NMP) can reach 3.8 mg/ml. GQDs with different sizes, structures and defect contents were obtained by using different graphitic carbon precursors for exfoliation. Hereby we synthesized high-defects GQDs (HD-GQDs) and low-defects GQDs (LD-GQDs) from acetylene black and nano-graphite, respectively. By luminescent and absorbance investigations, different light absorption and photoluminescence (PL) properties were identified relevant to the defect characters. The different edge structures, defect contents and sizes of GQDs are responsible for the variation of luminescent properties induced by changing the excitation wavelength and the pH values of the GQDs dispersions. Attributed to the high water dispersancy, excellent biocompatibility and controllable fluorescent performances, the as-synthesized HD-GQDs show high potential as fluorescence nanoprobes for bioimaging.
Co-reporter:Chao Shi, Jianyong Gao, Ming Wang, Yiran Shao, Liping Wang, Dalin Wang and Yingchun Zhu
Biomaterials Science 2016 vol. 4(Issue 4) pp:699-710
Publication Date(Web):17 Feb 2016
DOI:10.1039/C6BM00009F
The biocompatibility and antibacterial properties of hydroxyapatite (HAp) bioceramics are crucial in medical applications. However, it is still a challenge to control HAp with antibacterial ability while maintaining other biological properties in the development of bioactive bone implants. Herein, we report functional silver ion substituted HAp bioceramics with excellent osteoconductivity and efficient antibacterial activity and propose a stern-interface induced antibacterial mechanism of such bioactive ceramics. In this antibacterial process, the concentration of Ag+ at the stern-interface of Ag/HAp bioceramics is nearly 5 times higher than that in the bulk solution due to the trace dopant Ag+ enrichment in the stern layer of the electric double layer at the negatively charged surface of Ag/HAp bioceramics. Trace Ag-doping in HAp induces a positive shift of zeta potential and increase of hydrophilicity, which may help inhibit bacterial proliferation. The positive osteoblast adhesion, proliferation and differentiation of ultra-trace doped Ag/HAp are also demonstrated through actin cytoskeleton staining, MTT and alkaline phosphatase (ALP) activity assays. This work may enlighten us on the artificial design of novel smart anti-infective bone grafts using ultra-trace functional elements and also suggest its potential applications in orthopedic surgery and bone osseointegration.
Co-reporter:Ming Wang, Liping Wang, Chao Shi, Tian Sun, Yi Zeng and Yingchun Zhu
Physical Chemistry Chemical Physics 2016 vol. 18(Issue 31) pp:21789-21796
Publication Date(Web):11 Jul 2016
DOI:10.1039/C6CP03230C
Aluminum (Al) is a trace element found in hard tissues, and the induction of bone diseases by Al accumulation has generated interest in the role and mechanism of Al in bone metabolism. Because hydroxyapatite (HA) constitutes the main inorganic content of human hard tissues, the biological effect of Al in human hard tissues is closely related to the intrinsic state of Al-doped HA (Al-HA). However, few investigations to date have focused on the crystallography of Al-HA. Herein, we determined the crystallographic characteristics and energy states of Al-HA by conducting theoretical and experimental studies. Al-HA [Ca10−1.5xAlx(PO4)6(OH)2] with a defect structure was synthesized. XRD patterns and morphology images revealed that doping of Al decreased the crystallinity and the HA nanocrystal size. The optimized crystal structure indicated that Al was preferentially substituted for Ca(2) and Ca vacancies appeared at the Ca(2)1 site. Al doping locally distorted the regularity and integrity of the HA crystal structure, leading to the occurrence of Ca2+ vacancies and the displacement and rotation of OH− and [PO4]3− chains. The total energy of Al-HA increased and the stability decreased. Consequently, Al-HA might be readily degraded by osteoclasts and bone resorption could be accelerated. The destruction and over-resorption of bones caused by excessive Al could result in abnormal bone metabolism. The present findings not only provide the first crystallographic information on the disruptive effects of Al doping in HA but also complement the present understanding of the mechanisms underlying Al-induced bone diseases.
Co-reporter:Jingke Fu, Yiran Shao, Liyao Wang and Yingchun Zhu
Nanoscale 2015 vol. 7(Issue 16) pp:7275-7283
Publication Date(Web):16 Mar 2015
DOI:10.1039/C5NR00706B
Excess reactive oxygen species (ROS) have been proved to damage cancer cells efficiently. ROS overproduction is thus greatly desirable for cancer therapy. To date, ROS production is generally uncontrollable and outside cells, which always bring severe side-effects in the vasculature. Since most ROS share a very short half-life and primarily react close to their site of formation, it would be more efficient if excess ROS are controllably produced inside cancer cells. Herein, we report an efficient lysosome-controlled ROS overproduction via a pH-responsive catalytic nanosystem (FeOx-MSNs), which catalyze the decomposition of H2O2 to produce considerable ROS selectively inside the acidic lysosomes (pH 5.0) of cancer cells. After a further incorporation of ROS-sensitive TMB into the nanosystem (FeOx-MSNs-TMB), both a distinct cell labeling and an efficient death of breast carcinoma cells are obtained. This lysosome-controlled efficient ROS overproduction suggests promising applications in cancer treatments.
Co-reporter:Jinjin Gao, Chunxia Li, Jingfang Zhou, Liqiang Lu, Chengjian Zhao and Yingchun Zhu
RSC Advances 2015 vol. 5(Issue 26) pp:20357-20364
Publication Date(Web):20 Feb 2015
DOI:10.1039/C5RA01329A
Alumina coatings have wide-ranging applications by virtue of their inherent wear and corrosion resistance and attractive dielectric and diffusion barrier properties. In many cases, they do not meet the antibacterial demand to eliminate microbiologically-induced corrosion and diseases. The aim of this work is to prepare plasma sprayed alumina–nanosilver (Al2O3/Ag) coatings and investigate their antibacterial properties with various compositions. Moreover, Al2O3/Ag coatings are optimized to use minimum amounts of silver nanoparticles (AgNPs) and exhibit excellent antibacterial properties. Al2O3 coatings with five different amounts of AgNPs were deposited on titanium alloys substrates by plasma spray. The Al2O3/Ag coatings, which were denoted as A1, A2, A3, A4 and A5, were prepared by using α-Al2O3 powders containing 1 ppm, 10 ppm, 100 ppm, 1000 ppm and 10000 ppm AgNPs, respectively. The composition and morphology of Al2O3/Ag coatings were investigated by X-ray diffraction and scanning electron microscopy. The antibacterial activity of Al2O3/Ag coatings was tested using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model strains of Gram negative and Gram positive bacteria, respectively. The bacterial adhesion was also examined by employing both of the bacteria to observe bacterial adhesion status and evaluate antibacterial property of as-prepared coatings. The results showed the Al2O3/Ag coatings with more than 10 ppm AgNPs exhibited strong antibacterial property against E. coli and S. aureus. Bacterial adhesion assays showed that A2–A5 had anti-adhesive property of E. coli and S. aureus, which was in accordance with the antibacterial results. Moreover, the main factors influencing the antibacterial properties of Al2O3/Ag coatings were discussed with silver nanoparticles and hydrophobicity of the coatings.
Co-reporter:Jinjin Gao, Chengjian Zhao, Jingfang Zhou, Chunxia Li, Yiran Shao, Chao Shi, Yingchun Zhu
Applied Surface Science 2015 Volume 355() pp:593-601
Publication Date(Web):15 November 2015
DOI:10.1016/j.apsusc.2015.07.147
Highlights
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TiO2/Ag feedstock powders containing 1–10,000 ppm silver nanoparticles were double sintered and deposited by plasma spray.
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TiO2/Ag coatings were composed of pure rutile phase and homogeneously-distributed metallic silver.
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TiO2/Ag coatings with more than 10 ppm silver nanoparticles exhibited strong antibacterial activity against E. coli and S. aureus.
Co-reporter:Jingke Fu, Yang Wang, Yingchun Zhu
Materials Letters 2015 Volume 153() pp:89-91
Publication Date(Web):15 August 2015
DOI:10.1016/j.matlet.2015.04.043
●High reflectivity of hollow mesoporous silica nanospheres (HMSNs).●HMSNs reflect more than 90% of the UV–vis light in the wide range of 240–800 nm.●The unique structure and comparable size with the UV light cause the high reflectivity.●HMSNs can be used as effective UV shielding supporters for light-labile peroxides.We herein report the optical diffuse reflection properties of hollow mesoporous silica nanospheres (HMSNs). The HMSNs reflect more than 90% of the UV and visible light in the wide range of 240–800 nm and more than 70% of the UV light shorter than 240 nm, which are significantly higher than that of the bulk silica. The high reflectance of the HMSNs mainly arises from multiple scattering, which is caused by the disordered arrangement of nanospheres with thickness up to several hundred nanometers. Besides, the unique microstructure of HMSNs and the comparable size of HMSNs with UV light may also contribute to their high reflection according to the Mie scattering principles. Unlike semiconductor materials which shield UV light by absorbing UV light and generating reactive species, the HMSNs display extremely low absorption in the UV light region. The high UV light reflection properties as well as the specific hollow mesoporous structures of the HMSNs indicate their superior applications in UV light shielding devices.
Co-reporter:Chao Shi, Jianyong Gao, Ming Wang, Jingke Fu, Dalin Wang, Yingchun Zhu
Materials Science and Engineering: C 2015 Volume 55() pp:497-505
Publication Date(Web):1 October 2015
DOI:10.1016/j.msec.2015.05.078
•Ultra-trace Ag-doped HAp nanocrystals (from 0.04 ppm to 197 ppm) were synthesized.•Ultra-trace Ag-doped HAp nanocrystals possess higher protein adsorption than un-doped HAp.•Eu3 + was chosen as fluorescence labeling to verify cell-uptake property of HAp nanocrystals.•Ag/HAp (0.27 ppm, 2.2 ppm) possesses effective antibacterial ability with non-cytotoxicity.Hydroxyapatite (HAp) nanocrystals as the main inorganic component in hard tissue have been extensively studied for bone regeneration and dental implant treatment. However, failure of surgical reconstruction often occurs owing to the lack of effective antibacterial ability of HAp. It is still a challenge to develop artificial HAp with both efficient antibacterial ability and proper biological properties. Herein, a series of ultra-trace Ag-doped HAp nanocrystals have been elaborately prepared with the optimal doping concentration from 0.27 ppm to 2.2 ppm, which present non-cytotoxicity while possess effective bacteria reduction ability. Ultra-trace Ag-doped HAp nanocrystals possess higher protein adsorption than pure HAp nanocrystals due to the trace doping-induced less negative surface potential. The ultra-trace Ag-doped HAp nanocrystals showed effectively antibacterial ability, non-cytotoxicity and enhanced adsorbability that made them ideal materials for various biocompatible and antibacterial applications.The effective antibacterial activity and non-cytotoxicity of ultra-trace Ag doped hydroxyapatite nanocrystals make them ideal materials for various biocompatible and antibacterial applications.
Co-reporter:Jingke Fu, Yiran Shao, Chao Shi, Wenbo Bu and Yingchun Zhu
Journal of Materials Chemistry A 2014 vol. 2(Issue 40) pp:6984-6994
Publication Date(Web):11 Sep 2014
DOI:10.1039/C4TB01288G
Excessive free radicals are noxious for living organisms and lead to cell death. Destruction of malignant cells by reactive free radicals has been widely used in cancer treatment. A key consideration is how to allow targeted free radical attack on cancer cells and avoid unwanted side-effects. Herein, we develop an efficient intracellular free radical generation strategy against cancer cells by delivering active ingredients into cancer cells, where free radicals are selectively generated by a lysosomal bioactivation process. Artesunate (ART), which is non-toxic to normal cells, was chosen as the free radical source and transported into cells with a hollow mesoporous silica-based delivery system (ART@HMS). To selectively activate the ART@HMS inside cancer cells, a high-bioactive Fe/O cluster-mesoporous silica nanosystem (Fe/O-MSN) was elaborately prepared. Under the bioactivation of the lysosome, the low-dose ART@HMS together with biocompatible Fe/O-MSN induced significant intracellular generation of toxic free radicals and efficient death of cancer cells. This selective intracellular free radical generation strategy is encouraging for its development into an effective low-cost cancer therapy.
Co-reporter:Jingke Fu, Yingchun Zhu and Yang Zhao
Journal of Materials Chemistry A 2014 vol. 2(Issue 22) pp:3538-3548
Publication Date(Web):04 Apr 2014
DOI:10.1039/C4TB00387J
Free radicals are toxic entities known to cause cellular damage and to mediate cell death. We herein develop a controlled free radical generation strategy for cancer therapy via pH-responsive release of benzoyl peroxide (BPO) in tumor cells and producing free radicals to mediate cell death. BPO as the free radical resource was encapsulated into a chitosan (Cs)-coated mesoporous silica nanocomposite (BPO@HMSNs-Cs). The mesoporous silica carrier improved the BPO solubility by preventing its crystallization and promoted its stability by inclusion. Chitosan imparted the nanocomposite pH-responsive BPO release capacity with enhanced BPO release in simulated acidic tumor media (pH 6.5) and minor release in simulated normal tissue media (pH 7.4). The enhanced free radical generation in tumor media further led to significantly higher cytotoxicity in the tumor at acidic pH 6.5 than at physiological pH 7.4. The free radical-mediated cytotoxicity of BPO@HMSNs-Cs was verified by the observation of free radical-induced green fluorescence in cells. This pH-responsive free radical generation nanocomposite may provide new opportunities for controlled drug delivery and cancer therapy.
Co-reporter:Ming Wang, Jianyong Gao, Chao Shi, Yingchun Zhu, Yi Zeng, and Dalin Wang
Crystal Growth & Design 2014 Volume 14(Issue 12) pp:6459-6466
Publication Date(Web):October 24, 2014
DOI:10.1021/cg5013044
The oriented hierarchical architecture of hydroxyapatite (HA) shows excellent performance in multiple functions in human hard tissues such as bone and teeth. It is a challenge to mimic the architecture of biomineralization products. This study introduces a simple method for the hierarchical architecture of pure stoichiometric HA by a one-pot hydrothermal process without adding any organic molecules. The reaction process is researched by XRD, FT-IR, SEM, and TEM, and the HA crystal growth mechanism is discussed. The short rod-like HA nanocrystals are orderly assembled into micrometer-sized platy particles with the DCPD (CaHPO4·2H2O, brushite) shape retained. The ordered HA hierarchical architectures are achieved through topotactic transformation due to the crystal structural similarity from DCPD through DCPA (CaHPO4, monetite) to HA. It is found for the first time that the growth of HA crystals on DCPA is accompanied by orientation relationship of HA [1̅10] // DCPA [110] and HA (112) // DCPA (1̅12). The resemblance between the crystal structures promotes the direct phase transition. The results provide new insights into the formation mechanism of ordered HA hierarchical architectures and give hints for designing hierarchically assembled nanoarchitecture in synthetic work.
Co-reporter:Shisen Song, Bo You, Yingchun Zhu, Yandan Lin, Yin Wu, and Xiaochun Ge
Crystal Growth & Design 2014 Volume 14(Issue 1) pp:38-45
Publication Date(Web):December 6, 2013
DOI:10.1021/cg401047a
A novel high level oriented assembly of zinc hydroxide carbonate nanocrystals in chitosan was fabricated via a hydrothermal process. Hydrated chitosan acts as a template supporting and structure-directing reagents for the formation and assembly of zinc hydroxide carbonate nanocrystals. Zinc hydroxide carbonate nanocrystals were heterogeneously nucleated at the interface of hydrated chitosan crystallization regions through hydrogen bonding, lattice geometrical matching, and stereochemical matching interactions with ordered chitosan chains. The products obtained at different reaction stages were characterized with SEM, TEM, XRD, XPS, and TGA. The antifungal activity assays of CZHC, zinc hydroxide carbonate, chitosan, chitosan simply blended with zinc hydroxide carbonate (1:1), and nano zinc oxide were investigated. The study exhibited that the CZHC nanocrystals showed an antifungal activity against Cotton Verticillium, Rhizopus, and Mucorales and showed a better antifungal activity than other test samples against Rhizopus.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Lin Gan, Fang-fang Xu
Journal of Luminescence 2014 Volume 148() pp:334-337
Publication Date(Web):April 2014
DOI:10.1016/j.jlumin.2013.12.050
•Varied valence Eu ions in LaAlO3 phosphor was identified and quantified by PL.•EELS were employed to identify the charge state of Eu ions and to quantify the content of Eu2+/Eu3+.•Results confirmed the application of PL and EELS in determining the charge state of rare earth ions.For many instances in phosphor materials, mixed valence Eu co-existing phenomenon has been widely reported. It is then of great importance and necessity to identify the charge state and to quantify the content of varied valence Eu ions, because the luminescent properties of phosphors are closely dependent on the valence state of Eu ions and its content. Photoluminescence (PL) spectrum on the emission profile and electron energy loss spectrum (EELS) about the M-edges carry useful information on the valence state of Eu ions. In this work, PL and EELS were employed to identify the charge state of Eu ions in LaAlO3 phosphor, basing on the different emission profile of PL and M5/M4 ratio of EELS signals for varied valence Eu ions. And the relative content ratio of Eu2+/Eu3+ for these incorporated Eu ions in LaAlO3 host was quantified by the PL and EELS.
Co-reporter:Yang Zhao
Journal of Materials Science 2014 Volume 49( Issue 10) pp:3665-3673
Publication Date(Web):2014 May
DOI:10.1007/s10853-014-8073-y
Low-energy ultrasound (LEUS) shows distinct potential as a safe therapeutic strategy for cancer treatment. Herein, mesoporous silica nanoparticles with closed-end cavities as sensitive nanoagents are prepared for effective cancer cell killing, when synergistically combined with mild LEUS (1 MHz, ≤1.0 W cm−2). The closed-end cavities can entrap gas bubbles, and provide a large number of cavitation nucleation sites, which could lead to drastically amplify ultrasonic cavitation effect by responding to the mild LEUS (1 MHz, ≤1.0 W cm−2). Significant killing effect against cancer cells is observed, when cells are treated by synergetic combination of mild LEUS and the nanoagents with closed-end cavities, showing distinct dose dependency on the nanoagents and irradiation intensity. Nevertheless, the killing effect is disappeared when the closed-end cavities are destructed. Moreover, no obvious cytotoxicity is observed when either the nanoagents or the LEUS is applied alone. The research may open up application opportunities of mild low-energy ultrasound for cancer therapy.
Co-reporter:Dr. Yang Zhao;Dr. Yingchun Zhu;Dr. Jingke Fu;Dr. Lianzhou Wang
Chemistry – An Asian Journal 2014 Volume 9( Issue 3) pp:790-796
Publication Date(Web):
DOI:10.1002/asia.201301333
Abstract
β-Cyclodextrin (β-CD)-capped mesoporous silica nanoparticles with hydrophobic internal nanovoids were prepared and used for effective cancer cell killing in synergistic combination with low-energy ultrasound (≤1.0 W cm−2, 1 MHz). The water-dispersible nanoparticles with hydrophobic internal nanovoids can be taken up by cancer cells and subsequently evoke a remarkable cavitation effect under irradiation with mild low-energy ultrasound (≤1.0 W cm−2, 1 MHz). A significant cancer cell killing effect was observed in cancer cells and in a mouse xenograft tumor model treated with the nanoagents together with the low-energy ultrasound, showing a distinct dependence on the concentration of nanoagents and ultrasound intensity. By contrast, an antitumor effect was not observed when either low-energy ultrasound or nanoagents were applied alone. These findings are significant as the technique promises a safe, low-cost, and effective treatment for cancer therapy.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu
Materials Research Bulletin 2014 51() pp: 197-201
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.12.015
Co-reporter:Zhi-yong Mao;Ying-chun Zhu;Yang Wang;Lin Gan
Journal of Materials Science 2014 Volume 49( Issue 13) pp:4439-4444
Publication Date(Web):2014 July
DOI:10.1007/s10853-014-8140-4
Tricolor emission Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) phosphors were synthesized by the conventional solid-state reaction method, and their photoluminescence properties were investigated. Ce3+-, Eu2+-, or Sm3+-doped Ca2SiO4 phosphors showed typical blue, green, or red luminescence in the CIE1931 chromaticity diagram, respectively. In addition, the luminescence efficiency of the tricolor emission Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) phosphors was evaluated. A series of white light-emitting diode (LED) prototypes were fabricated by combining near-UV LED chip and the as-prepared tricolor emission phosphors with various ratios in weight. White LED prototypes with tunable correlated color temperature and color-rendering index values were realized by controlling the amount of phosphors. The presented results indicated the potential application of Ca2SiO4:Ln (Ln = Ce3+, Eu2+, Sm3+) phosphors in near-UV white LED.
Co-reporter:Chao Shi, Yingchun Zhu, Huofei Qian, Liqiang Lu
Materials Research Bulletin 2014 51() pp: 161-166
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.12.010
Co-reporter:Fang Li, Yingchun Zhu, Zhiyong Mao, Yunli Wang, Qichao Ruan, Jianlin Shi and Congqin Ning
Journal of Materials Chemistry A 2013 vol. 1(Issue 11) pp:1579-1583
Publication Date(Web):18 Jan 2013
DOI:10.1039/C3TB00362K
Macromolecules responsive to both electric field and pH are modified on the outlets of mesoporous silica nanospheres to form a novel dual-mode drug delivery system. Dual drug delivery modes are indicated by the release patterns obtained by simulating the body’s gastric and intestinal fluid ex vivo. In a pH 1.4 release medium (simulated gastric fluid, SGF) without an alternating electric field, only 8.5% of the total payload is found to leach in 8 h, whereas 50.3% and 60.2% of the total payload are released in the same time period by elevating the pH of the release medium or applying an alternating electric field. The two stimuli signals can work independently or corporately to regulate the release kinetics to form a dual-mode drug delivery mechanism, which makes it more flexible for use in certain complicated situations.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Lin Gan, Yi Zeng, Fang-fang Xu, Yang Wang, Hua Tian, Jian Li, Da-jian Wang
Journal of Luminescence 2013 Volume 134() pp:148-153
Publication Date(Web):February 2013
DOI:10.1016/j.jlumin.2012.08.057
Tricolor emission in a same Ca3Si2O7 host with independent Ln (LnCe3+, Eu2+, Tb3+) dopants is demonstrated to construct a near-UV white light emitting diode (LED). The luminescence properties and thermal quenching properties, as well as the applications in near-UV white LED are investigated. These phosphors show typical blue, red, and green, three-basal-color, luminescence in the CIE chromaticity diagram for Ce3+, Eu2+ and Tb3+ dopants, respectively. Thermal quenching properties show that the luminescence thermal stability strongly depends on the different dopant types; better thermal quenching property of Ce3+ and Tb3+ is recorded in comparison with that of Eu2+. The white LED prototype fabricated with near-UV chip and as-prepared tricolor phosphors exhibits acceptable CIE chromaticity coordinates (0.32, 0.30) with a CCT of 6000 K and a CRI of 87, indicating the potential application of Ca3Si2O7:Ln phosphors in near-UV white LED.Highlights► Tricolor Ca3Si2O7: Ln phosphors were demonstrated to construct near-UV white LED. ► Eu2+ doped Ca3Si2O7 red-emitting phosphor was confirmed by this work once again. ► Thermal quenching properties for Ca3Si2O7:Ln phosphors were reported for the first time. ► Performances of fabricated white LED indicated the potential application of phosphors.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Yi Zeng, Lin Gan, Yang Wang
Journal of Luminescence 2013 Volume 143() pp:587-591
Publication Date(Web):November 2013
DOI:10.1016/j.jlumin.2013.06.015
•Concentration quenching and its influence on Ca3Si2O7: Tb3+ phosphors were demonstrated.•Two concentration quenching mechanisms, cross relaxation and energy migration were investigated.•Bluish-green, green and yellow–green emission was traced owing to the concentration quenching effects.Concentration quenching processes and the resulting influence on the photoluminescence properties of Ca3Si2O7:Tb3+ green-emitting phosphors are investigated in this work. Cross relaxation between activators and energy migration from activators to quenching center, are assigned to be the quenching mechanism for 5D3 emissions and 5D4 emissions of Tb3+ ions, respectively. Concentration quenching processes and the corresponding energy transfer are discussed in detail. The intensity ratio of the emissions from 5D4 to that from 5D3 is tuned by the concentration quenching processes. As a result, bluish-green, green and yellow–green emitting color is induced by concentration quenching effects for Tb3+ ions doped Ca3Si2O7 phosphors.
Co-reporter:Yongsheng Zhou and Yingchun Zhu
RSC Advances 2013 vol. 3(Issue 19) pp:6779-6782
Publication Date(Web):20 Mar 2013
DOI:10.1039/C3RA40896E
The relatively high melting temperature and the inability to process Ta structures via conventional processing routes have limited the acceptance of tantalum, in spite of its excellent biocompatibility. Here we report, for the first time, a method of processing Ta to create porous structures consisting of self-assembled nanowire bundles from three-dimensional (3D) microporous Ta scaffolds via facile high temperature heat treatment. Porous Ta samples have been characterized for their mechanical properties. The results show that the Young's modulus of porous Ta can be tailored between 0.06 and 1.69 GPa by changing the heat treatment temperature between 2200 °C and 2400 °C. These porous Ta structures resemble cancellous bone structures on the micro/macroscale. This remarkably simple process can be employed as an enabling technique for applications in nanotechnology and biotechnology.
Co-reporter:Yongsheng Zhou, Yingchun Zhu
Materials Letters 2013 Volume 99() pp:8-10
Publication Date(Web):15 May 2013
DOI:10.1016/j.matlet.2013.02.068
This study reports the preparation of a novel porous tantalum (Ta) scaffold and the compressive property of the metallic implants. Porous Ta was produced by a thermal heat treatment method and subsequent circulating water treatments. The porous Ta scaffolds were characterized by scanning electron microscopy, quasi-static uniaxial compressive tests, and protein adsorption. It was found that the scaffold had three-dimensional hierarchical porous structures with pore size ranging from nanometer to micrometer scale. Mechanical test results showed that the scaffold has sufficient compressive strength to meet the requirements of implantation. Protein adsorption results indicated that the Ta foams are expected to be used as biocompatible implant materials.Highlights► Porous Ta was produced by a thermal heat treatment method. ► The scaffold has three-dimensional hierarchical porous structures. ► The scaffold has sufficient compressive strength.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Lin Gan, Fang-fang Xu, Yang Wang and Da-jian Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 3) pp:824-826
Publication Date(Web):24 Nov 2011
DOI:10.1039/C1JM15084G
White-light emission is realized through assembling a blue-emitting amorphous phase on a yellow-emitting Ca-SiAlON: Eu2+ phosphor particle in the form of a coating. The variation of the yellowish–white–blue color is traced with the control of a blue-emitting coating formed via in situ penetration of silicon oxide into a Ca-SiAlON network.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Lin Gan, Yi Zeng, Fang-fang Xu, Yang Wang, Hua Tian and Da-jian Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 37) pp:19839-19848
Publication Date(Web):07 Aug 2012
DOI:10.1039/C2JM33581F
SiAlON-based crystal–glass composite phosphors with tunable yellow-green-blue emission are exploited. Substitution of Al–N by Si–O in a SiAlON lattice and the introduction of a Si–Al–O–N glass phase are induced by melting corrosion as SiAlON polycrystal powders were heat-treated with nano-SiO2 additive. The melting corrosion process involving liquid penetration, solid dissolution, liquid transportation is discussed and assigned to the origin of morphology transformation. The substitution extent and the glass content are identified to increase with the addition of nano-SiO2 additive. The resultant tunable photoluminescence of Eu2+ in the SiAlON lattice and Si–Al–O–N glass matrix and the microstructure evolution are detailed, respectively. The emission color of the SiAlON-based crystal–glass composite phosphors is traced continuously from yellow to green then to blue with the combination of changeable emissions of Eu2+ originated from the SiAlON phase and glass phase. This artful SiAlON-based crystal–glass composite phosphor shows flexible color-adjustable capability with the control of SiO2 melting corrosion, indicating the potential applications in lighting and display fields.
Co-reporter:Yunli Wang, Yingchun Zhu, Jingjing Chen and Yi Zeng
Nanoscale 2012 vol. 4(Issue 19) pp:6025-6031
Publication Date(Web):20 Jul 2012
DOI:10.1039/C2NR31256E
A three-dimensionally (3D) ordered freestanding porous platinum (Pt) nanowire array electrode (PPNWAE) with pores of several nanometers in size and a Pt nanowire array electrode (PNWAE) without pores were facilely fabricated by metal electrodeposition and direct integration with a Pt disk electrode. The unusual PPNWAE with high active area showed excellent sensitivity (0.36 mA cm−2 mM−1) and a wide detection range (4.5 μM–27.1 mM) to hydrogen peroxide (H2O2). A glucose oxidase (GOD)-based biosensor (PPNWAE/GOD) with a considerably wide detection range (4.5 μM–189.5 mM) to glucose was demonstrated. Furthermore, a lower detection limit, higher sensitivity and smaller value of Michaelis–Menten constant km were recorded for PPNWAE-based biosensors compared with PNWAE-based biosensors. Particularly, the response current to glucose of PPNWAE/GOD was ca. 100% higher than that of PNWAE/GOD and the response current to H2O2 of PPNWAE was ca. 50% higher than that of PNWAE, owing to the granular and rougher porous nanowire surface enabling greater bioactivity for GOD. The selectivity of PPNWAE/GOD glucose biosensor was also estimated.
Co-reporter:Zhiyong Mao, Yingchun Zhu, Yi Zeng, Fangfang Xu, Zhen Liu, Guohong Ma, Zuliang Du and Wentong Geng
CrystEngComm 2012 vol. 14(Issue 23) pp:7929-7933
Publication Date(Web):16 Jul 2012
DOI:10.1039/C2CE25758K
An Al-doped silicon nitride-based semiconductor is successfully synthesized by the chemical vapor deposition (CVD) technique. Optical, electrical and electronic properties are investigated in detail which reveal that Al-doped α-Si3N4 presents a typical semi-conductive character with a band-gap of 2.65 eV and an electrical conductivity of ∼6.11 × 10−2 S cm−1. Al-doping complex (substitutional accompanied with interstitial Al ions in the (102) plane) in α-Si3N4 lattice and its resulting abnormal crystal growth property are discussed. Experimental and theoretical calculation results indicate that this peculiar Al-doping complex in the (102) plane is responsible for the shrinkage of the band-gap for Al-doped α-Si3N4. The presented results demonstrate that this Al-doped α-Si3N4 may open up many applications opportunities in optics, electronics and photoelectronics fields.
Co-reporter:Yong-sheng Zhou, Ying-chun Zhu, Jing-jing Chen, Gao-hui Du, Bing-she Xu
Materials Letters 2012 Volume 86() pp:139-141
Publication Date(Web):1 November 2012
DOI:10.1016/j.matlet.2012.07.045
We present a chemical vapor deposition method to prepare cobalt sulfide nanostructure-filled carbon nanotubes (CNTs) by pyrolysis of dimethyl sulfide (C2H6S) over Co/MgO catalyst. C2H6S is used as the carbon and sulfur source. The synthesized products were characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, transmission electron microscopy, electron diffraction, and photoluminescence (PL) spectroscopy, and the results demonstrate that the encapsulated matter in CNTs is cubic Co9S8. Due to the presence of the specific defects in the CNT surface and the CNT Y-junction, and the dielectric screening of the cobalt sulfide nanostructures within the CNTs, the cobalt sulfide nanostructure-filled CNTs exhibit an intensive violet PL emission at 425 nm.Highlights► Carbon nanotubes have been prepared by pyrolysis of C2H6S over Co catalyst. ► The nanotubes are filled with nanoparticles, nanorods, and nanowires. ► The product exhibits extensive violet photoluminescence emission at 425 nm.
Co-reporter:Fang Chen, Yingchun Zhu
Microporous and Mesoporous Materials 2012 150() pp: 83-89
Publication Date(Web):
DOI:10.1016/j.micromeso.2011.07.023
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Qin-ni Fei, Da-jian Wang
Journal of Luminescence 2011 Volume 131(Issue 5) pp:1048-1051
Publication Date(Web):May 2011
DOI:10.1016/j.jlumin.2011.01.020
Photoluminescence and lifetime decay properties of varied valence Eu were employed to investigate the luminescence mechanism of green-light emission positioned at ∼515 nm for full color emission LaAlO3 phosphor co-doped with Eu2+ and Eu3+. The enhanced 5D2→7F3 transition emission of Eu3+ was assigned for this green emission. Energy transfer between Eu2+ and 5D2 level of Eu3+ was proposed, which results in the enhancement of 5D2→7F3 transition emission. In addition, energy transfer relations between host-Eu and charge transfer state (CTS)-Eu were also discussed associated with the PLE spectra and band schemes.Research Highlights► A white-light is achieved from valence-mixed Eu in full-color LaAlO3. ► A unique green-light emission at 515 nm is examined by spectrum and decay time. ► The energy transfer happens in between di- and tri- valent Eu and host as well. ► We propose the 5D2-7F3 transition for trivalent Eu leads to that green emission.
Co-reporter:Yingchun Zhu ; Huijuan Liu ; Fang Li ; Qichao Ruan ; Hua Wang ; Masahiro Fujiwara ; Lianzhou Wang ;G. Q. (Max) Lu
Journal of the American Chemical Society 2010 Volume 132(Issue 5) pp:1450-1451
Publication Date(Web):January 15, 2010
DOI:10.1021/ja907560y
Here we report the design of a new external electric field-controlled release system using functional dipolar molecules as nanoimpellers. The dipolar molecule 4-(3-cyanophenyl)butylene, which can reorient in response to external electric fields with different frequencies because of its strong inherent dipole moment, was synthesized and grafted onto the inner surfaces of mesopores. Under an alternating electric field, the swinging flexible molecular chains consequently push guest molecules out of the pore voids. This innovative approach to controlled release may provide important application opportunities in tumor treatment with a number of advantages in terms of local release with targetability, external remote control, and the nonelectrochemical nature of the process.
Co-reporter:Fang Li;Bo You;Donghui Zhao;Qichao Ruan;Yi Zeng;Chuanxian Ding
Advanced Functional Materials 2010 Volume 20( Issue 4) pp:669-676
Publication Date(Web):
DOI:10.1002/adfm.200901245
Abstract
A series of hydrogels with continuously regulatable release behavior can be achieved by incorporating hydrogen bonding and π–π stacking co-switches in polymers. A poly(nitrophenyl methacrylate-co-methacrylic acid) hydrogel (NPMAAHG) for control over drug release is fabricated by copolymerizing 4-nitrophenyl methacrylate and methacrylic acid using ethylene glycol dimethacrylate as a crosslinker. The carboxylic acid groups and nitrylphenyl groups form hydrogen bonds and π–π stacking interactions, respectively, which act as switches to control the release of guest molecules from the polymers. As revealed by the simulated gastrointestinal tract drug release experiments, the as-synthesized NPMAAHG hydrogels can be regulated to release only 4.7% of drugs after 3 h in a simulated stomach and nearly 92.6% within 43 h in the whole digestive tract. The relation between the release kinetics and structures and the mechanism of the smart release control are analyzed in terms of diffusion exponent, swelling interface number, drug diffusion coefficient, and velocity of the swelling interface in detail. The results reveal that the release of guest molecules from the hydrogels can be continuously regulated for systemic administration by controlling the ratio of the hydrophilic hydrogen bonds and the hydrophobic π–π stacking switches.
Co-reporter:Junwu Xiao, Yingchun Zhu, Qichao Ruan, Yanyan Liu, Yi Zeng, Fangfang Xu and Linlin Zhang
Crystal Growth & Design 2010 Volume 10(Issue 4) pp:1492-1499
Publication Date(Web):February 22, 2010
DOI:10.1021/cg9001016
Carbonated hydroxyapatite is a main inorganic component of hard tissues in vertebrates, which usually appears as orderly arranged superstructures in tissues and exhibits excellent biological and mechanical properties. Recently, mimicking the structure and composition of organisms in the field of biomaterials and tissue engineering has caused much attention. Herein, a family of orderly arranged textures composed of two-dimensional carbonated hydroxyapatite in nanoscale was prepared in the complex matrix of succinylated gelatin and cetyltrimethyl ammonium bromide, which is an analogue of bone in calcified turkey tendon. The building blocks of carbonated hydroxyapatite nanosheets elongate along the c-axis direction and self-organize into well-aligned bundles. This study may offer an example to design and synthesize laminated materials and may provide new evidence in support of the hypothesis that hierarchical structures in nature result from cooperative interactions between biological membrane and crystal growth.
Co-reporter:Jianhui Yuan, Yingchun Zhu, Heng Ji, Xuebing Zheng, Qichao Ruan, Yaran Niu, Ziwei Liu, Yi Zeng
Applied Surface Science 2010 Volume 256(Issue 16) pp:4938-4944
Publication Date(Web):1 June 2010
DOI:10.1016/j.apsusc.2010.03.006
Abstract
A promising WC–Co–Cu–BaF2/CaF2 self-lubricating wear resistant coating was deposited via atmospheric plasma spraying (APS) process by using homemade feedstock powders composed of WC–Co, Cu and BaF2/CaF2 eutectic. The as-prepared cermet coatings had better frictional behavior comparing with the WC–Co coating. Moreover, the often-occurred decarburization of WC in APS process was noticeably improved due to the binding of copper and BaF2/CaF2 phase, which not only offered effective solid lubrication, but also acted as bind phases to mend the microstructure and protected WC from decomposition. The optimized specimen contained 10 wt.% Cu and 10 wt.% BaF2/CaF2 in a WC–Co matrix, which had excellent frictional and wear performance. The wear mechanism of the self-lubricating wear resistant coating was discussed with the microstructures, compositions and mechanical properties of the composite materials in detail.
Co-reporter:Donghui Zhao, Yingchun Zhu, Fang Li, Qichao Ruan, Shengmao Zhang, Linlin Zhang, Fangfang Xu
Materials Research Bulletin 2010 45(1) pp: 80-87
Publication Date(Web):
DOI:10.1016/j.materresbull.2009.08.015
Co-reporter:Qichao Ruan, Yingchun Zhu, Fang Li, Junwu Xiao, Yi Zeng, Fangfang Xu
Journal of Colloid and Interface Science 2009 Volume 333(Issue 2) pp:725-733
Publication Date(Web):15 May 2009
DOI:10.1016/j.jcis.2009.02.003
The layer-by-layer (LbL) assembly as a simple and effective method has been extensively used to prepare polyelectrolyte films but the buildup mechanism is expected to be further clarified. In this work, the structure and formation mechanism of LbL-assembled heparin/chitosan multilayer composite films were characterized by electrochemical system, scanning electron microscope and atom force microscope. The results revealed that the film grew linearly in the first 10 bilayers based on measured linear increase of film resistance with number of layers, while the film grew exponentially in the later 10 bilayers based on measured nonlinear increase of film resistance. The charge-transfer resistance increased in an oscillatory way or a linear way at different growing stages, which was discussed with their formation mechanism and the interfacial structure on electrode. A buildup mode of the LbL film was suggested based on the structural and electrochemical characters.The film resistance (Rf)(Rf) and the charge-transfer resistance (Rct)(Rct) increase in diverse ways at different growing stages, revealing the buildup mechanism of layer-by-layer assembled films.
Co-reporter:Junwu Xiao;Yanyan Liu;Yi Zeng ;Fangfang Xu
Journal of Biomedical Materials Research Part B: Applied Biomaterials 2009 Volume 89B( Issue 2) pp:543-550
Publication Date(Web):
DOI:10.1002/jbm.b.31246
Abstract
A composite coating on Ti6Al4V implant was prepared from alginate and gelatin particles through a dip-coating method to control the release of the water soluble drug gentamicin and improve the surface properties of the implant. Gentamicin was dissolved in the coating or bonded to gelatin particles through Schiff base reaction. The drug release experiments in vitro showed that about 10% of gentamicin was released within 0.5 h, the release lasted for 10 days, and the release from the composite coating was dependent on the pH value. The composite coating could induce the formation of apatite on the coating surface, which was fully covered after 7 days immersing in SBF solution. In addition, Ti6Al4V plate with the composite coating had excellent antibacterial activity against Staphylococcus aureus. All of the results provided the possibility that this composite coating might be applied as a controlled release system to deliver the water soluble drug, and as a bioactive, biodegradable layer on the bio-inert implant surface to induce the formation of apatite and actively bond to the surrounding tissue in vivo. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Co-reporter:Xuefeng Du;Tao Yang;Yue Shen;Yi Zeng
Journal of Nanoparticle Research 2009 Volume 11( Issue 5) pp:1179-1183
Publication Date(Web):2009 July
DOI:10.1007/s11051-008-9519-4
GaN/C nanocables were synthesized via a thermochemical process. The GaN/C nanocables were composed of single crystalline GaN nanowire cores with a mean diameter of 80 nm and parallel carbon sheathes with a thickness of several nanometers. We find that GaN nanocables were partially evolved into waved GaN nanowires and discontinuously ordered nanodots within the carbon sheaths due to the decomposition of GaN at high temperature regions. Both the carbon sheathes and GaN nanowire cores show a high degree of crystalline perfection. This method may be applied to coat a wide range of nanostructures with carbon sheathes and prepare various hetrostructures, which may serve as potential building blocks in nanodevices.
Co-reporter:Junwu Xiao;Yanyan Liu
Journal of Materials Science: Materials in Medicine 2009 Volume 20( Issue 4) pp:889-896
Publication Date(Web):2009 April
DOI:10.1007/s10856-008-3631-y
An asymmetric coating composed of gelatin and hydroxyapatite on Ti6Al4V alloy implant was prepared to control the release of water-insoluble drug ibuprofen and improve the surface properties of the implant. The asymmetric coating developed into a thin dense outer layer and a thick porous inner layer using a dip-coating method and a succedent phase-inversion process. The drug loading ranged from 10 to 30% (w/w), and depended on the immersion time and drug concentration in the quenching solution. The in vitro release from this system was always at an approximately zero-order rate and at least lasted for 30 days. The in vitro studies in SBF revealed that the coating could induce the formation of apatite, and was fully covered after 14 days soaking in SBF solution. This asymmetric coating had better bioactivity of inducing the formation of apatite in vitro, compared with pure gelatin coating and bare Ti6Al4V implant.
Co-reporter:Yanyan Liu;Yi Zeng;Fangfang Xu
Nanoscale Research Letters 2009 Volume 4( Issue 3) pp:
Publication Date(Web):2009 March
DOI:10.1007/s11671-008-9227-0
A sensitive amperometric biosensor based on gold nanoelectrode array (NEA) was investigated. The gold nanoelectrode array was fabricated by template-assisted electrodeposition on general electrodes, which shows an ordered well-defined 3D structure of nanowires. The sensitivity of the gold NEA to hydrogen peroxide is 37 times higher than that of the conventional electrode. The linear range of the platinum NEA toward H2O2is from 1 × 10−6to 1 × 10−2 M, covering four orders of magnitudes with detection limit of 1 × 10−7 M and a single noise ratio (S/N) of four. The enzyme electrode exhibits an excellent response performance to glucose with linear range from 1 × 10−5to 1 × 10−2 M and a fast response time within 8 s. The Michaelis–Menten constantk m and the maximum current densityimaxof the enzyme electrode were 4.97 mM and 84.60 μA cm−2, respectively. This special nanoelectrode may find potential application in other biosensors based on amperometric signals.
Co-reporter:Junwu Xiao, Yingchun Zhu, Yanyan Liu, Huijuan Liu, Yi Zeng, Fangfang Xu and Lanzhou Wang
Crystal Growth & Design 2008 Volume 8(Issue 8) pp:2887
Publication Date(Web):June 19, 2008
DOI:10.1021/cg701233y
Polymorph selection of biominerals is an interesting phenomenon as observed in some natural shells, which contain distinct polymorphs of calcium carbonate in one organism. The reason why distinct polymorphs present in different portions of organisms has attracted increasing attention. In this work, we selectively synthesized calcite nanoparticles and vaterite hexagonal plates under conditions with different morphologies of chitosan chains. Calcite nanoparticles were homogeneously nucleated in the chitosan sol, and capsulated by semirigid polycation chitosan chains through electrostatic attraction. The metastable vaterite crystals in hexagonal symmetry were heterogeneously nucleated at the interface of chitosan gel, and stabilized through stereochemically matched hydrogen bonding interactions with flexible chitosan chains, which reduces the unstable (001) faces surface energy.
Co-reporter:Hui-Juan Liu, Ying-Chun Zhu
Materials Letters 2008 Volume 62(Issue 2) pp:255-257
Publication Date(Web):31 January 2008
DOI:10.1016/j.matlet.2007.05.011
1D nanostructures of ternary chalcogenide, ZnCdS–Cd nanocables and ZnCdS nanotubes, have been synthesized through a thermochemical process. The as-prepared nanocables consist of a single-crystal Cd core with a mean diameter of 90 nm and a single-crystal ZnCdS sheath with a thickness of 8 nm. The Cd core and the ZnCdS sheath are coaxially arranged. The as-prepared nanotube has the same structure as the sheath of ZnCdS–Cd nanocables with a hexagonal Zn0.78Cd0.22S phase. The formation of ZnCdS nanotubes results from the evaporation of the Cd core. The cathodoluminescence spectrum of ZnCdS–Cd nanocables displays an emission peak at 490 nm, and the emission peak is just between those of ZnS and CdS.
Co-reporter:Y. C. Zhu ;W. T. Geng
The Journal of Physical Chemistry C 2008 Volume 112(Issue 23) pp:8545-8547
Publication Date(Web):May 17, 2008
DOI:10.1021/jp712147a
Two-dimensional silver nanodisks were self-assembled in ⟨111⟩ crystallography orientations forming a three-dimensional architecture. The kinetics studies of interface growth reveal that the Cu2+ ion diffusion interface diminished the concentration convection and electric convection at the growing interface. With the fluctuation greatly reduced, the effect of lattice anisotropy of the growing interface starts to dominate, which induces highly faceted regular patterns with a stable growing interface. First-principles density functional theory calculations clarified that the silver patterns grow consistently with their thermodynamic character of the face-centered-cubic phase, and show the crystallographical orientation.
Co-reporter:Jingke Fu and Yingchun Zhu
Journal of Materials Chemistry A 2017 - vol. 5(Issue 5) pp:NaN1004-1004
Publication Date(Web):2017/01/17
DOI:10.1039/C6TB02820A
Conventional chemotherapy uses potent toxic drugs to destroy cancer cells and always causes severe systemic toxicity in patients. In this respect, a smart and pH-switched prodrug/procatalyst co-delivery nanosystem is developed which is non-toxic toward normal cells and is inert during its delivery in the vasculature, while responsively functions in acidic lysosomes inside cancer cells. Synthetically, non-toxic artemisinin (ART) was used as the prodrug and loaded into the inner space of hollow mesoporous silica (HMS) nanoparticles (NPs). Subsequently, Fe3O4 NPs were efficiently capped onto pore outlets of HMS via acid labile acetal linkers (ART@HMS-Fe3O4). ART@HMS-Fe3O4 was stable under neutral conditions (pH 7.4) with almost no leakage of ART. Upon exposure to the acidic lysosomal compartment (pH 3.8–5.0) in cells, the acetal linkers were hydrolyzed which led to sustained release of both ART and Fe3O4 NPs. Under the activation of the lysosomal environment, the liberated Fe3O4 NPs were metabolized to free iron ions and catalyzed the generation of high amounts of free radicals from the released ART in cells. In vitro cytotoxicity assay revealed excellent anticancer efficacy of this ART/Fe3O4 co-delivery nanosystem. The Fe3O4 NPs acted both as gatekeepers and procatalysts which inhibited ART from leakage during their delivery, while released ART and activated chain reactions to form free radicals in acidic lysosomes inside cancer cells. We visualize that this lysosomal environment-responsive ART@HMS-Fe3O4 nanosystem could serve as an efficient and desirable chemotherapeutic nanosystem for cancer therapy.
Co-reporter:Jingke Fu, Yiran Shao, Chao Shi, Wenbo Bu and Yingchun Zhu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 40) pp:NaN6994-6994
Publication Date(Web):2014/09/11
DOI:10.1039/C4TB01288G
Excessive free radicals are noxious for living organisms and lead to cell death. Destruction of malignant cells by reactive free radicals has been widely used in cancer treatment. A key consideration is how to allow targeted free radical attack on cancer cells and avoid unwanted side-effects. Herein, we develop an efficient intracellular free radical generation strategy against cancer cells by delivering active ingredients into cancer cells, where free radicals are selectively generated by a lysosomal bioactivation process. Artesunate (ART), which is non-toxic to normal cells, was chosen as the free radical source and transported into cells with a hollow mesoporous silica-based delivery system (ART@HMS). To selectively activate the ART@HMS inside cancer cells, a high-bioactive Fe/O cluster-mesoporous silica nanosystem (Fe/O-MSN) was elaborately prepared. Under the bioactivation of the lysosome, the low-dose ART@HMS together with biocompatible Fe/O-MSN induced significant intracellular generation of toxic free radicals and efficient death of cancer cells. This selective intracellular free radical generation strategy is encouraging for its development into an effective low-cost cancer therapy.
Co-reporter:Chao Shi, Jianyong Gao, Ming Wang, Yiran Shao, Liping Wang, Dalin Wang and Yingchun Zhu
Biomaterials Science (2013-Present) 2016 - vol. 4(Issue 4) pp:
Publication Date(Web):
DOI:10.1039/C6BM00009F
Co-reporter:Yiran Shao, Liyao Wang, Jingke Fu, Chao Shi, Jiaqiang Xu and Yingchun Zhu
Journal of Materials Chemistry A 2016 - vol. 4(Issue 35) pp:NaN5872-5872
Publication Date(Web):2016/08/10
DOI:10.1039/C6TB00734A
Tumor hypoxia is a negative prognostic factor in cancer radiotherapy, due in part to its role in causing resistance to radiotherapy. It has attracted extensive critical attention to radiation sensitizers by using active oxygen to improve radiotherapy outcome. Active oxygen delivery functional materials are promising candidates to transport active oxygen to tumor cells. Herein, we report an oxygen delivery functional material by using hollow mesoporous silica nanoparticles (HMSNs) as carriers, synthesizing sodium percarbonate (SPC) in the channels and cavity of HMSNs (SPC@HMSNs) and coating polyacrylic acid (PAA) on the functional materials (SPC@HMSNs–PAA). SPC@HMSNs–PAA could release more SPC in a simulated tumor acidic microenvironment (pH ∼ 6.5), which can provide oxygen to improve radiotherapy outcome even under low energy X-ray irradiation. The events induce obvious overproduction of reactive oxygen radicals to kill cancer cells with a significant effect. Meanwhile, no obvious cytotoxicity was observed when SPC@HMSNs–PAA applied alone. The radiosensitization of SPC@HMSNs–PAA on cancer cells, even exposure to low-energy X-ray irradiation, may suggest promising application in radiotherapy.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Lin Gan, Fang-fang Xu, Yang Wang and Da-jian Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 3) pp:NaN826-826
Publication Date(Web):2011/11/24
DOI:10.1039/C1JM15084G
White-light emission is realized through assembling a blue-emitting amorphous phase on a yellow-emitting Ca-SiAlON: Eu2+ phosphor particle in the form of a coating. The variation of the yellowish–white–blue color is traced with the control of a blue-emitting coating formed via in situ penetration of silicon oxide into a Ca-SiAlON network.
Co-reporter:Zhi-yong Mao, Ying-chun Zhu, Lin Gan, Yi Zeng, Fang-fang Xu, Yang Wang, Hua Tian and Da-jian Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 37) pp:NaN19848-19848
Publication Date(Web):2012/08/07
DOI:10.1039/C2JM33581F
SiAlON-based crystal–glass composite phosphors with tunable yellow-green-blue emission are exploited. Substitution of Al–N by Si–O in a SiAlON lattice and the introduction of a Si–Al–O–N glass phase are induced by melting corrosion as SiAlON polycrystal powders were heat-treated with nano-SiO2 additive. The melting corrosion process involving liquid penetration, solid dissolution, liquid transportation is discussed and assigned to the origin of morphology transformation. The substitution extent and the glass content are identified to increase with the addition of nano-SiO2 additive. The resultant tunable photoluminescence of Eu2+ in the SiAlON lattice and Si–Al–O–N glass matrix and the microstructure evolution are detailed, respectively. The emission color of the SiAlON-based crystal–glass composite phosphors is traced continuously from yellow to green then to blue with the combination of changeable emissions of Eu2+ originated from the SiAlON phase and glass phase. This artful SiAlON-based crystal–glass composite phosphor shows flexible color-adjustable capability with the control of SiO2 melting corrosion, indicating the potential applications in lighting and display fields.
Co-reporter:Jingke Fu, Yingchun Zhu and Yang Zhao
Journal of Materials Chemistry A 2014 - vol. 2(Issue 22) pp:NaN3548-3548
Publication Date(Web):2014/04/04
DOI:10.1039/C4TB00387J
Free radicals are toxic entities known to cause cellular damage and to mediate cell death. We herein develop a controlled free radical generation strategy for cancer therapy via pH-responsive release of benzoyl peroxide (BPO) in tumor cells and producing free radicals to mediate cell death. BPO as the free radical resource was encapsulated into a chitosan (Cs)-coated mesoporous silica nanocomposite (BPO@HMSNs-Cs). The mesoporous silica carrier improved the BPO solubility by preventing its crystallization and promoted its stability by inclusion. Chitosan imparted the nanocomposite pH-responsive BPO release capacity with enhanced BPO release in simulated acidic tumor media (pH 6.5) and minor release in simulated normal tissue media (pH 7.4). The enhanced free radical generation in tumor media further led to significantly higher cytotoxicity in the tumor at acidic pH 6.5 than at physiological pH 7.4. The free radical-mediated cytotoxicity of BPO@HMSNs-Cs was verified by the observation of free radical-induced green fluorescence in cells. This pH-responsive free radical generation nanocomposite may provide new opportunities for controlled drug delivery and cancer therapy.
Co-reporter:Fang Li, Yingchun Zhu, Zhiyong Mao, Yunli Wang, Qichao Ruan, Jianlin Shi and Congqin Ning
Journal of Materials Chemistry A 2013 - vol. 1(Issue 11) pp:NaN1583-1583
Publication Date(Web):2013/01/18
DOI:10.1039/C3TB00362K
Macromolecules responsive to both electric field and pH are modified on the outlets of mesoporous silica nanospheres to form a novel dual-mode drug delivery system. Dual drug delivery modes are indicated by the release patterns obtained by simulating the body’s gastric and intestinal fluid ex vivo. In a pH 1.4 release medium (simulated gastric fluid, SGF) without an alternating electric field, only 8.5% of the total payload is found to leach in 8 h, whereas 50.3% and 60.2% of the total payload are released in the same time period by elevating the pH of the release medium or applying an alternating electric field. The two stimuli signals can work independently or corporately to regulate the release kinetics to form a dual-mode drug delivery mechanism, which makes it more flexible for use in certain complicated situations.
Co-reporter:Ming Wang, Liping Wang, Chao Shi, Tian Sun, Yi Zeng and Yingchun Zhu
Physical Chemistry Chemical Physics 2016 - vol. 18(Issue 31) pp:NaN21796-21796
Publication Date(Web):2016/07/11
DOI:10.1039/C6CP03230C
Aluminum (Al) is a trace element found in hard tissues, and the induction of bone diseases by Al accumulation has generated interest in the role and mechanism of Al in bone metabolism. Because hydroxyapatite (HA) constitutes the main inorganic content of human hard tissues, the biological effect of Al in human hard tissues is closely related to the intrinsic state of Al-doped HA (Al-HA). However, few investigations to date have focused on the crystallography of Al-HA. Herein, we determined the crystallographic characteristics and energy states of Al-HA by conducting theoretical and experimental studies. Al-HA [Ca10−1.5xAlx(PO4)6(OH)2] with a defect structure was synthesized. XRD patterns and morphology images revealed that doping of Al decreased the crystallinity and the HA nanocrystal size. The optimized crystal structure indicated that Al was preferentially substituted for Ca(2) and Ca vacancies appeared at the Ca(2)1 site. Al doping locally distorted the regularity and integrity of the HA crystal structure, leading to the occurrence of Ca2+ vacancies and the displacement and rotation of OH− and [PO4]3− chains. The total energy of Al-HA increased and the stability decreased. Consequently, Al-HA might be readily degraded by osteoclasts and bone resorption could be accelerated. The destruction and over-resorption of bones caused by excessive Al could result in abnormal bone metabolism. The present findings not only provide the first crystallographic information on the disruptive effects of Al doping in HA but also complement the present understanding of the mechanisms underlying Al-induced bone diseases.
