ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2014
·Vol. 407
·期 6
·1721-1734
·
IF 3.578
Yang Fan,Bai Quan,Zhao Kailou,Gao Dong,Tian Lei
A novel dual-function mixed-mode stationary phase based on poly(glycidyl methacrylate- co -ethylene dimethacrylate) microspheres was synthesized by thiol–ene click chemistry and characterized by infrared spectroscopy and elemental analysis. The new system displays both hydrophobic interaction chromatography (HIC) character in a high salt concentration mobile phase, and weak cation exchange (WCX) chromatography character in a low salt concentration mobile phase. It can be used to separate proteins in both ion-exchange chromatography (IEC) mode and HIC mode. The resolution and selectivity of the stationary phase were evaluated in both HIC mode and IEC mode using protein standards. In comparison with the conventional WCX and HIC columns, the results were satisfactory and acceptable. Protein mass and bioactivity recoveries of more than 96 % can be achieved in both HIC mode and IEC mode using this column. The results indicate that the novel dual-function mixed-mode column in many cases can replace the use of two individual WCX and HIC columns. In addition, the effects on protein separation of different ligand structures in the dual-function stationary phase and the pH of the mobile phase used were also investigated in detail. The results show that electrostatic interaction of the ligand with proteins must match the hydrophobicity of the ligand, which is an important factor to prepare the dual-function stationary phase. On the basis of this dual-function mixed-mode chromatography column, a new two-dimensional liquid chromatography technology with a single column system was also developed in this study, and was used to renature and purify recombinant human interferon-γ from inclusion bodies. The mass recovery, purity, and specific bioactivity obtained for the purified recombinant human interferon-γ were 87.2 %, 92.4 %, and 2.8 × 10 7 IU/mg, respectively, in IEC mode, and 83.4 %, 95.2 %, and 4.3 × 10 7 IU/mg, respectively, in HIC mode. The results indicate that the dual-function mixed-mode stationary phase prepared in this study may aid in the development of new two-dimensional liquid chromatography technology with a single column for intensive proteomic studies, and it may also find applications in recombinant protein drug production since it can save column costs and simplify the biotechnological processes.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2014
·Vol. 406
·期 20
·4987-4995
·
IF 3.578
Fu Yu,Mo Hua-Yan,Gao Wen,Hong Jia-Ying,Lu Jun,Li Ping,Chen Jun
Xanthine oxidase (XOD) is a key oxidative enzyme to the pathogenesis of hyperuricemia and certain diseases induced by excessive reactive oxygen species. XOD inhibitors could provide an important therapeutic approach to treat such diseases. A new method using affinity selection-based two-dimensional chromatography coupled with liquid chromatography-mass spectrometry was developed for the online screening of potential XOD inhibitors from Radix Salviae Miltiorrhizae. Based on our previous study, the two-dimensional, turbulent-flow chromatography (TFC) was changed to a mixed-mode anion-exchange/reversed-phase column and one reversed-phase column. The developed method was validated to be selective and sensitive for screening XOD-binding compounds, especially weak acidic ones, in the extracts. Three salvianolic acids were screened from the Radix Salviae Miltiorrhizae extract via the developed method. The XOD inhibitory activities of salvianolic acid C and salvianolic acid A were confirmed, and their inhibitory modes were measured. Salvianolic acid C exhibited potent XOD inhibitory activity with an IC 50 of 9.07 μM. This work demonstrated that the developed online, two-dimensional TFC/LC-MS method was effective in discovering the binding affinity of new compounds from natural extracts for target proteins, even at low concentrations.
ᅟ
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-10
·
IF 2.481
Li Chen,Wang Zhuan-Hua,Yu Deng-Guang,Williams Gareth R
This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-13
·
IF 2.481
Li Chao,Ji Yang,Wang Can,Liang Shujing,Pan Fei,Zhang Chunlei,Chen Feng,Fu Hualin,Wang Kan,Cui Daxiang
Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early gastric cancer is a great challenge. Herein, we choose the CdSe/ZnS (core-shell) quantum dots (QDs) as prototypical materials, synthesized one kind of a new amphiphilic polymer including dentate-like alkyl chains and multiple carboxyl groups, and then used the prepared amphiphilic polymer to modify QDs. The resultant amphiphilic polymer engineered QDs (PQDs) were conjugated with BRCAA1 and Her2 monoclonal antibody, and prepared BRCAA1 antibody- and Her2 antibody-conjugated QDs were used for in vitro MGC803 cell labeling and in vivo targeted imaging of gastric cancer cells. Results showed that the PQDs exhibited good water solubility, strong photoluminescence (PL) intensity, and good biocompatibility. BRCAA1 antibody- and Her2 antibody-conjugated QD nanoprobes successfully realized targeted imaging of in vivo gastric cancer MGC803 cells. In conclusion, BRCAA1 antibody- and Her2 antibody-conjugated PQDs have great potential in applications such as single cell labeling and in vivo tracking, and targeted imaging and therapeutic effects' evaluation of in vivo early gastric cancer cells in the near future.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Pharmaceutical Innovation
·
2014
·Vol. 10
·期 1
·13-20
·
IF 1.25
Kong Lijun,Hu Jinxia,Qin Dan,Yan Peng
Combined techniques like fluorescence, circular dichroism (CD), and Fourier transform infrared (FT-IR) were applied to study the interaction between ifosfamide-loaded superparamagnetic iron oxide nanoparticles (ISION) and human serum albumin (HSA) at physiological pH. The fluorescence results showed the existance of a static quenching mode for HSA-ISION interaction. The binding constant at 298 K was in the order of 10 5 M −1 , showing high affinity occurred between ISION and HSA. The thermodynamic parameters obtained at three different temperatures (288, 298, and 308 K) indicated that the dominant binding forces are the electrostatic forces, for the values of the enthalpy change (Δ H °) and entropy change (Δ S °) were found to be −1.31 × 10 4 J · mol −1 and 55.4 J · mol −1 · K −1 , respectively. Fluorescence resonance energy transfer (FRET) analysis revealed that the average binding distance ( r ) between Trp of HSA and ISION was 5.25 nm. The results of CD and FT-IR spectra demonstrated that the secondary structure of HSA was altered in the presence of ISION.
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2014
·Vol. 22
·期 1
·203-214
·
IF 3.033
Qin Wang,Li Zhijun,Li Jixiang,Zhang Lihua,Liu Ruilai,Liu Haiqing
Two types of photochromic azobenzene hydroxypropyl celluloses (azo-HPCs) are prepared by homogeneous etherification of HPC with 4-(2,3-epoxypropoxy)-azobenzene and bromoethoxy-azobenzene in N,N -dimethylacetamide under mild conditions. The degree of substitution of azo moiety of azo-HPCs is tuned in the range of 0.6–1.8 by adjusting the mole ratio of azobenzene to HPC. Their chemical structures and properties are characterized by elemental analysis, infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and differential scanning calorimetry. Compared to other cellulose ethers and esters with glass transition temperature (T g ) of normally larger than 100 °C, the azo-HPC derivatives display very low T g of ca. 20–40 °C. The azobenzenoxy-ethoxy-HPC is a thermotropic liquid crystal which displays cholesteric texture at 165 °C while cooling from its isotropic melt. Their solutions show almost fully reversible trans – cis – trans transition upon alternating irradiation of UV and visible light.
✓ 已验证
产品关联
DOI
高影响因子
Electrocatalysis
·
2014
·Vol. 6
·期 2
·211-219
·
IF 2.089
Ouyang Lei,Miao Yuqing,Xu Lina,Xiao Mingshu,Liang Xiaocai,Li Weiwei,Yang Yang
Molecular self-assembly is an important aspect of bottom-up approaches for the nanofabrication of functional materials. The self-assembly of smaller-size units like ions has yet to be studied further. The self-adsorption of Bi III without applied potential and electrochemical deposition of Bi/Bi III were studied and compared through cyclic voltammetry. Both of them exhibit two pairs of redox peaks assigned to the (2 × 2)-Bi adlayer and incommensurate ( p × √3)-2 Bi adlayer. The adsorption of two Bi surface phases is related with the Bi salt concentration and adsorption time. Within a certain concentration or time range, the adsorption approaches to be saturated due to the surface limitation of self-adsorbed surface layers. The (2 × 2)-Bi adlayer firstly adsorbs to the active sites of Au where there is strong interaction between Bi and Au. With the increase of time, more Bi adsorbs onto the unoccupied sites of Au with a relatively weak interaction force to form a denser ( p × √3)-2 Bi layer. A new pair of redox peaks appears for the electrodeposition of the Bi/Bi III bulky layer which is easily stripped from the Au surface through a consecutive potential scan. Comparatively speaking, the adsorbed (2 × 2) and ( p × √3)-2 Bi adlayers are stable in the same potential scanning condition due to the strong interaction between the two surface Bi layers and the below Au atoms. Such a controllable self-adsorption of the Bi III ultrathin layer on foreign substrates exhibits a potential for the modification of materials in the size of ions.
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2014
·Vol. 22
·期 4
·2891-2899
·
IF 2.757
Luo Zhuanxi,Qiu Zhaozheng,Chen Zheng,Du Laing Gijs,Liu Aifen,Yan Changzhou
Increased application of titanium dioxide and zinc oxide nanoparticles (nano-TiO 2 and nano-ZnO) raises concerns related to their environmental impacts. The effects that such nanoparticles have on environmental processes and the bacteria that carry them out are largely unknown. In this study, ammonia-oxidizing bacteria (AOB) enrichment cultures, grown from surface sediments taken from an estuary wetland in Fujian Province, China, were spiked with nano-TiO 2 and nano-ZnO (with an average size of 32 and 43 nm, respectively) at predicted environmentally relevant concentrations (≤2 mg L −1 ) to determine their impacts on ammonia oxidation and the mechanisms involved. Results showed that higher nano-TiO 2 concentrations significantly inhibited ammonia oxidation in enrichment cultures. It is noteworthy that the average ammonia oxidation rate was significantly correlated to the Shannon index, the Simpson’s index, and AOB abundance. This suggested that ammonia oxidation inhibition primarily resulted from a reduction of AOB biodiversity and abundance. However, AOB biodiversity and abundance as well as the average ammonia oxidation rate were not inhibited by nano-ZnO at predicted environmentally relevant concentrations. Accordingly, an insignificant correlation was established between biodiversity and abundance of the AOB amoA gene and the average ammonia oxidation rate under nano-ZnO treatments. AOB present in samples belonged to the β- Proteobacteria class with an affinity close to Nitrosospira and Nitrosomonas genera. This suggested that identified impacts of nano-TiO 2 and nano-ZnO on ammonia oxidation processes can be extrapolated to some extent to natural aquatic environments. Complex impacts on AOB may result from different nanomaterials present in aquatic environments at various ambient conditions. Further investigation on how and to what extent different nanomaterials influence AOB diversity and abundance and their subsequent ammonia oxidation processes is therefore required.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2013
·Vol. 29
·期 6
·1214-1218
·
IF 0.735
Li Xian-liang,Zuo Wei-wen,Luo Meng,Shi Zuo-sen,Cui Zhan-chen,Zhu Song
Thiol-functionalized MCM-41 type mesoporous silica particles(MSPs) were prepared and loaded with silver chloride to act as antibacterial agents. The antibacterial activity of the silver chloride loaded MSPs(AgCl-MSPs) was evaluated by the minimum bactericidal concentration(MBC) against Candida albicans (ATCC 10231). The AgCl-MSPs with the highest antibacterial activity were then dispersed in hybrid coatings with different mass ratios to fabricate antibacterial coatings. The antibacterial activity of the coatings was tested against Candida albicans (ATCC 10231) and Streptococcus mutans (ATCC 25175). The resulting antibacterial coatings exhibited high antibacterial activity, good adhesion to the substrate and high hardness.
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2013
·Vol. 144
·期 2
·268-277
·
IF 2.244
Ding Yue,Li Xiaohong,Pan Huiyan,Wu Peng
Abstract Ru nanoparticles entrapped in ordered mesoporous carbons (CMK-3) served as an efficient and reusable catalyst for liquid-phase hydrogenation of benzaldehyde and its derivatives under our tested conditions (medium hydrogen pressure, room temperature, water as solvent). The Ru nanoparticles can be well stabilized by CMK-3 ordered mesoporous carbons so that the Ru leaching was below the detection limit of ICP-AES. Therefore, the Ru/CMK-3 catalyst can be used for at least five times without distinct loss in activity or selectivity for the hydrogenation of benzaldehyde. It is worthy of note that the Ru/CMK-3 catalyst was more efficient than the commercial Ru/C and homemade Ru/AC catalyst for the liquid-phase hydrogenation of benzaldehyde. The Ru/CMK-3 catalyst can also catalyze the liquid-phase hydrogenation of nitrobenzene and its derivatives with high conversions and excellent selectivities under optimal conditions. Graphical Abstract
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2013
·Vol. 18
·期 1
·105-113
·
IF 2.279
Li Hongying,Wang Xueliang,Yu Zhangyu
An electrochemical sensor for simultaneous determination of dopamine (DA), uric acid (UA), guanine (G), and adenine (A) has been constructed by copolymerizing melamine monomer and Ag ions on a glassy carbon electrode (GCE) with cyclic voltammetry. The poly-melamine and nano Ag formed a hybridized film on the surface of the GCE. The morphology of the film was characterized by scanning electron microscope. The electrochemical and electrocatalytic properties of this film were characterized by cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry (SWV). In 0.1 M phosphate buffer solution (pH 4.5), the modified electrode resolved the electrochemical response of DA, UA, G, and A into four well-defined voltammetric oxidation peaks by SWV; the oxidation peak current of DA, UA, G, and A increased 13-, 6-, 7-, and 9-fold, respectively, compared with those at the bare GCE and the SWV peak currents of DA, UA, G, and A with linear concentrations in the ranges of 0.1–50, 0.1–50, 0.1–50, and 0.1–60 μM, respectively. Based on this, a method for simultaneous determination of these species in mixture was setup. The detection limits were 10 nM for DA, 100 nM for UA, 8 nM for G, and 8 nM for A.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2013
·Vol. 15
·期 9
·1-11
·
IF 2.175
Lu Weili,Luo Chenghao,Li Yu,Feng Yiyu,Feng Wei,Zhao Yunhui,Yuan Xiaoyan
CoSn/carbon composite nanofibers were prepared by electrospinning followed by heat treatment. Uniform morphologies and microstructures were observed by scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction. The results demonstrated that well-dispersed nanoparticles of CoSn intermetallic compound and Sn with diameter of about 30–50 nm embedded in carbon nanofibers were prepared after carbonization at 850 °C. Compared with pure carbon nanofibers without the nanoparticles, CoSn/carbon composite nanofibers showed a high reversible capacity and excellent cycling performance, resulting from the formation of CoSn intermetallic nanoparticles and buffering by the carbon nanofiber matrix. The nanofiber mats with good flexibility were utilized as anodes in lithium-ion batteries, and the CoSn/carbon composite nanofibers exhibited a good fibrous morphology after the discharge/charge processes. Results indicated that electrospinning could be a feasible method to prepare Co–Sn–C composite nanofibers as anodes in lithium-ion batteries.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）