CHEMISTRY OF MATERIALS
·
2017
·
IF 9.466
Bin-Wen Liu,Min-Yi Zhang,Xiao-Ming Jiang,Shu-Fang Li,Hui-Yi Zeng,Guo-Qiang Wang,Yu-Hang Fan,Yong-Fei Su,Chunsen Li,Guo-Cong Guo,Jin-Shun Huang
Two new polar polyselenides Rb4Ge4Se12 (1) and Cs4Ge4Se12 (2) with rarely reported dimeric [Ge2Se4(μ-Se2)]4– units were synthesized. They present large second-harmonic generation (SHG) intensities of 7.5 and 6.5 times that of the benchmark AgGaS2 with type I phase-matching behavior, high laser-induced damaged thresholds, a wide transmission region and congruently melting behavior, making them excellent candidates for IR nonlinear optical (NLO) applications. The SHG functional motifs of both compounds are determined to be [Ge2Se4(μ-Se2)]4– unit by time-dependent density functional theory calculation, which further reveals that charge transfers from the lone pairs of terminal Se atoms to the five σ* orbitals of five-membered ring Ge2Se3 have a predominant contribution to the total SHG effect.
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PHARMACEUTICAL DEVELOPMENT AND TECHNOLOGY
·
2017
·
IF 1.86
Shengyu Zhang,Liuwan Zhao,Nanqin Qiu,Yanjun Liu,Bohui Xu,Hongyan Zhu
Hypoxia, an outstanding characteristic of various solid tumors, has been considered a critical factor of aggressive tumor phenotypes, poor clinical prognosis, and increased expression of the multidrug-resistant gene. Therefore, it is critical to develop a drug delivery system to enhance the delivery effect of the antitumor drug in the hypoxic tumor. We constructed two types of tumor targeting micelles based on chitosan and evaluated their properties in targeting hypoxic tumors. Chitosan-based micelles consisted of a hydrophobic group octyl group, a hydrophilic polyethylene glycol, tumor targeting ligands glucosamine or folic acid, and a transmembrane peptide 9-d-arginine. The molecular structure, morphology, size distribution, zeta potential, and biosafety of two micelles were characterized. Oil-soluble CdSe quantum dots were used as a fluorescent probe to evaluate the hypoxic tumor cell targeting properties of the micelles. Moreover, HepG2 human hepatocellular carcinoma cells and HeLa human cervical carcinoma cells were used as in vitro models. We demonstrated that, under hypoxic conditions, two chitosan micelles showed better targeting ability to HepG2 and HeLa cells, which enhanced the effect of antitumor drugs by specifically targeting transport in hypoxic tumors. Therefore, chitosan micelles may be a potential drug delivery system that can be used to deliver antitumor drugs to hypoxic tumors.
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PubMed
高影响因子
CHEMOSPHERE
·
2017
·
IF 4.208
Xu Chen,Yong Sik Ok,Dinesh Mohan,Charles U. Pittman,Xiaomin Dou
The increasingly wide use of semiconductor nanocrystals inevitably leads to their release into aquatic environment. The aggregation behaviors of 3-mercaptopropionic acid-capped CdSe/CdS core-shell quantum dots (MPA-QDs) under various water chemistry conditions were examined and their removal using Fe 3+ and Al 3+ coagulants was evaluated. Cationic species rather than concentrations affected the stability of MPA-QDs. Adding 2 mM Ca 2+ led to a much larger ζ-potential decrease and particle size increase than adding 150 mM K + at each tested solution pH. This indicated that complexation and depletion of surface-bound carboxyl groups by divalent Ca 2+ has a more pronounced effect than compression of the electrical double layer by high concentrations of monovalent K + . The presence of humic acid increased the stability of MPA-QDs, which might increase negative surface charging via overcoating or bind to the surface of MPA-QDs. The nanoparticles exhibited similar aggregation kinetics patterns in tap water and seawater, but varying patterns in the lake water because of the co-existence of 2.3 mM total of Ca 2+ and Mg 2+ . MPA-QDs (5 mg L −1 ) were readily coagulated by 2.4 mM Al 3+ or 1.2 mM Fe 3+ in tap water. Al 3+ and Fe 3+ can bind with carboxyl groups of the surface capping ligands, neutralize the negative charges on the surface of MPA-QDs and decrease the electrostatic repulsion forces to induce MPA-QDs aggregation. In addition, MPA-QDs could be bound with and wrapped into the flocs of hydrolysis products of coagulants. The results reported here could help broaden our understanding of the impacts and remediation of water-dispersed core-shell QD nanoparticles.
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高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2016
·Vol. 18
·期 2
·1-11
·
IF 2.101
Du Yingying,Yang Ping,Matras-Postolek Katarzyna,Wang Junpeng,Che Quande,Cao Yongqiang,Ma Qian
A silanization process was employed to transfer hydrophobic quantum dots (QDs) prepared via an organic route at high temperature into water phase. The QDs were further coated with a thin organic SiO 2 shell to form QDs@SiO 2 composite nanoparticles by ligand exchange or remaining initial organic ligands on the surface. In this study, QDs with different ligands, either trioctylphosphine oxide (TOPO) or oleic acid (OA), were employed to investigate the effects of ligands on the reverse micelles in preparing QDs@SiO 2 nanoparticles. In the preparing process, hydrophobic QDs were silanized by partially hydrolyzed tetraethyl orthosilicate (TEOS). For TOPO-capped CdSe QDs, surface TOPO ligands were completely replaced by partially hydrolyzed TEOS. As for OA-capped CdSe/Cd
x
Zn 1− x
S QDs, surface OA ligands were partially replaced. It was found that the ligand exchange drastically reduced the photoluminescence (PL) efficiency of CdSe QDs. Furthermore, the cytotoxicity studies of QDs@SiO 2 have been carried out in detail. The results indicate that CdSe/Cd
x
Zn 1− x
S QDs@SiO 2 composite nanoparticles exhibit lower cytotoxicity compared with CdSe QDs@SiO 2 , because the SiO 2 shell and remained OA ligand layer can effectively prevent the leakage of toxic Cd 2+ ions. Meanwhile, it was found that these CdSe/Cd
x
Zn 1− x
S QDs@SiO 2 nanocomposites could keep excellent PL properties even for 24 h incubating with Siha cells, which indicating that our prepared composite nanoparticles are potentially applicable for cell imaging in biological systems.
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Journal of Materials Chemistry A
·
2016
·Vol. 4
·期 11
·4125-4133
·
IF 8.262
Li Chen,Weilin Chen,Huaqiao Tan,Jiansheng Li,Xiaojing Sang,Enbo Wang
Quantum dot sensitized solar cells with high theoretical conversion efficiency, low production cost and a simple production process have received great attention in recent years. For CdSe-sensitized cells, the most significant defect of CdSe is that it has the weak absorption between 550 and 600 nm and no absorption after 650 nm, so it is crucial to find a wide spectrum photosensitizer to make up for the defect. Here, wide spectrum and pure inorganic Donor–Acceptor (D–A) Type Polyoxometalate (POM) K6H4[α-SiW9O37Co3(H2O)3]·17H2O (denoted as T) is firstly introduced into QDSCs as a collaborative cosensitizer with CdSe. The T has a visible characteristic peak centering between 550 and 600 nm, and also has stronger absorption after 650 nm, which could make up for the defect of CdSe to constitute a wide spectrum of absorption. The fluorescence spectrum, surface photovoltage spectrum, ultraviolet photoelectron spectroscopy spectrum and solid diffuse spectrum were used to explore the photosensitivity of T. In addition, the D–A type POM can act as a good intermediate for the injection of electrons and improve the visible photocurrent response; meanwhile, it can obviously reduce the dark current and increase the electron lifetime, which can solve the problem about the high recombination at the QD/TiO2/electrolyte interface. In general, the best photovoltaic performance of T and CdSe cosensitized solar cells is increased to 6.59% (Jsc = 18.37 mA cm−2, Voc = 0.57 V, FF = 0.63), which is improved by 32.33% compared to those of the pure CdSe-sensitized cells (Jsc = 16.20 mA cm−2, Voc = 0.50 V, FF = 0.61, η = 4.98%).
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FOOD CHEMISTRY
·
2016
·
IF 4.052
Zi Xu,Yong Fang,Yue Chen,Wenjian Yang,Ning Ma,Fei Pei,Benard Muinde Kimatu,Qiuhui Hu,Weifen Qiu
The protective capacity of Se-containing protein hydrolysates with molecular weight below 1 kDa (SPHs-3), against Pb 2+ -induced damage in PC12 and RAW264.7 cells, was investigated in this study. The cell viability, levels of reactive oxygen species (ROS), lactate dehydrogenase (LDH), superoxide dismutase (SOD), nitric oxide (NO), malondialdehyde (MDA) and glutathione (GSH) in cell were analyzed. Results showed that 100 μg/ml of SPHs-3 pretreatment could significantly increase cell viability by 24.9% and 23.0% in Pb 2+ -treated PC12 and RAW264.7 cells, respectively ( P < 0.01). The levels of ROS, NO, LDH and MDA were reduced by 32.2%, 68.2%, 79.7% and 73.7% in 100 μg/ml SPHs-3 pretreated PC12 cells, respectively ( P < 0.01). SPHs-3 pretreatment was also associated with increases of SOD activity and GSH content in cells. In conclusion, SPHs-3 could protect cells against Pb 2+ -induced cytotoxicity, suggesting that Se-enriched rice may be a feasible candidate to improve health standard of the Pb 2+ -pollution population.
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高影响因子
Materials Today Chemistry
·
2017
·
IF 0
Yan Zhang,Ying Xu,Chao Wei,Yuanying Zhang,Liu Yang,Zhongchen Song,Meidong Lang
Herein, novel multi-responsive injectable polyester hydrogels were reported based on the diselenide-containing poly(ε-caprolactone) copolymers ((mPEG-PCL-Se) 2 ). The (mPEG-PCL-Se) 2 solution remained a free-flowing state at ambient temperature but spontaneously turned into a semisolid hydrogel upon heating to physiologic temperature. The phase transition temperature was examined to be dependent on the composition and aqueous concentration of the copolymers. More importantly, the thermo-responsive hydrogels were endowed with oxidation and reduction-triggered degradation by the incorporation of diselenide groups. Accordingly, the degradation of poly(ε-caprolactone)-based hydrogels was greatly improved and the rate of degradation was well regulated by the concentration of hydrogen peroxide (H 2 O 2 ) or glutathione (GSH). This superior stimuli-responsive degradation could lead to an enhanced drug release of encapsulated drug (Doxorubicin, DOX). Thus the oxidation and reduction-triggered degradable diselenide-containing poly(ε-caprolactone) hydrogels would offer great potential for the controlled drug delivery.
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JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Xiaojun He,Hao Ma,Jingxian Wang,Yuanyang Xie,Nan Xiao,Jieshan Qiu
A hydroxide-template strategy coupled with in-situ chemical activation is reported for the first time to fabricate porous carbon nanosheets (PCNSs) from coal tar. The thin PCNSs feature abundant short pores accessible for fast ion transport and high specific surface area up to 3235 m 2 g −1 for ion adsorption. As electrodes for supercapacitors , the PCNSs show a high capacitance of 296.2 F g −1 at 0.05 A g −1 in 6 M KOH electrolyte, an excellent rate performance with a capacitance of 220.7 F g −1 at 20 A g −1 and a superior cycle stability with over 97.2% capacitance retention after 11000 charge-discharge cycles at 3.5 A g −1 . This work paves a new way for efficient fabrication of sheet-like carbon materials with tuned porous structure from polycyclic aromatic hydrocarbons for high performance supercapacitors .
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Nanoscale
·
2017
·Vol. 9
·期 8
·2824-2835
·
IF 7.367
Zhi-Qiang Zhou,Li-Yun Yang,Ren Yan,Jie Zhao,Yu-Qi Liu,Lu Lai,Feng-Lei Jiang,Thomas Maskow,Yi Liu
Although cation exchange (CE) has been studied for many years and some mechanisms were proposed, there is still a knowledge gap in CE and problems such as the need for high temperature and it being time-consuming are still unaddressed. We developed a new mild strategy for CE by introducing a new ideal template and first applied this doping strategy to detect Cd2+ and Hg2+. This strategy adopted Mn-doped ZnSe quantum dots (QDs) as the template and the introduction occurs via a two-step CE reaction: first Zn2+ was partially substituted by X (X = Cd2+, Hg2+, Cu2+, Ag+ or Pb2+), later Mn2+ (in the deep structure of QDs) was substituted by X. Remarkably, Mn2+ in the lattice can be easily substituted by a dopant and its replacement by a dopant helps to bury the metal ions. The ultra-fast introduction of Cd2+ and Hg2+ (70 minutes for Cd2+ and 19 minutes for Hg2+) was realized at room temperature; other metal ions such as Ag+, Cu2+ and Pb2+ can be buried at 50 °C. This mild reaction temperature offers a solution for introducing impurities without sacrificing the interfacial structure of nanocrystals. HRTEM, XPS and ICP measurements were applied to analyze the introduction process. Furthermore, the spectroscopic method was employed to analyze the introduction, migration and distribution of metal ions. Then, we proposed a mechanism for the chemical conversion of nanocrystals by CE. Through this strategy, full-color light-emitting doped QDs were fabricated. Strikingly, a new turn-on probe for the detection of Cd2+ and Hg2+ with improved selectivity was developed by adopting this doping strategy. The detection limit is 36 nM for Cd2+ and 20 nM for Hg2+, which is competitive with the limit of detection reported by other groups using QDs as sensors.
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高影响因子
Biomaterials Science
·
2017
·Vol. 5
·期 4
·669-677
·
IF 4.21
Chao Wei,Yan Zhang,Zhongchen Song,Yiru Xia,Heng Xu,Meidong Lang
Stimuli-responsive nanocarriers have been limited for bench-to-bedside translation mainly because the stimuli sensitivity and responsive rate are not high enough to ensure sufficient drug concentration at the target sites for superior therapeutic benefits. Herein, we reported an enhanced bioreduction-responsive and biodegradable nanocarrier based on the amphiphilic poly(ester urethane) copolymers (PAUR-SeSe) bearing multiple diselenide groups on the backbone. The copolymer could spontaneously self-assemble into stable micelles in aqueous medium with an average diameter of 68 nm, which could be rapidly disassembled in a reductive environment as a result of the reduction-triggered cleavage of diselenide groups. Furthermore, the PAUR-SeSe micelles showed an enhanced drug release profile and cellular uptake compared with the disulfide-containing analogue (PAUR-SS). CCK8 assays revealed that the antitumor activity of DOX-loaded PAUR-SeSe micelles was much higher than that of DOX-loaded PAUR-SS micelles. Besides, the blank micelles and degradation products were nontoxic up to a tested concentration of 50 μg mL−1. Therefore, the enhanced therapeutic efficacy and good biocompatibility demonstrated that this drug nanocarrier had great potential for smart antitumor drug delivery applications.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 27
·期 7
·6656-6664
·
IF 1.798
Lin Yibing,Lin Yu,Wu Jihuai,Zhang Xiaolong,Fang Biaopeng
In this study, after CdS quantum dots sensitized ZnO hierarchical spheres (ZnO HS), we used a simple process to deposit CdSe QDs on ZnO by spin-coating-based SILAR, and applied to photoanodes of quantum dots-sensitized solar cells. Before CdS and CdSe QDs deposition, the ZnO HS photoanodes were modified by Zn(CH 3 COO) 2 ·2H 2 O methanol solution to further enhance the open-circuit voltage and power conversion efficiency (PCE). The program of modifying photoanodes and the number of CdSe spin-SILAR cycles are evaluated on the optical and electrochemical properties of the cells. As a result, a high energy conversion efficiency of 2.49 % was obtained by using modified ZnO HS/CdS photoanode under AM 1.5 illumination of 100 mW cm −2 . And further decorated by the CdSe QDs, the ZnO HS/CdS/CdSe cell achieved a PCE of 5.36 % due to the modification of ZnO HS nanostructure, the enhanced absorption in the visible region, the lower recombination reaction and higher electron lifetime.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 31
·25656-25661
·
IF 3.289
Zhixiang Jiang,Katarzyna Matras-Postolek,Ping Yang
Several kinds of hydrophobic quantum dots (QDs) including CdSe, CdTe, CdSe/CdxZn1−xS, and CdTe/CdSe/ZnSe were fabricated via organic synthesis to observe morphology variation during shell coating. CdSe QDs prepared at a relatively high temperature revealed a hexagonal structure and rod morphology. On being coated with a CdxZn1−xS shell, tetrahedron and rod morphologies were observed. It was found that the reaction temperature and injection rate play important roles. The photoluminescence properties of the core/shell QDs depended strongly on their preparation conditions such as temperature and ligands. For CdSe cores created at a relatively low temperature, CdxZn1−xS shell coating resulted in the formation of cubic CdSe/CdxZn1−xS core/shell QDs. This is ascribed to the role of a CdS interlayer. In contrast, multishell CdTe/CdSe/ZnSe QDs revealed a spherical morphology. Furthermore, the self-assembly of QDs with hexagonal structures occurs while regular assembled structures were not observed for QDs with a cubic morphology according to their transmission electron microscopy images. This is ascribed to a dipole force between QDs. This phenomenon is just related to the morphology and crystal structures rather than their composition.
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