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1. FYCHWQDE-based affinity chromatography of IgG: Effect of ligand density and purification from human serum | |||
XUE Aiying,YU Linling,SUN Yan | |||
Chemical Engineering 26 April 2017 | |||
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Abstract:In our previous work, it has reported on the identification of the octapeptide ligand FYCHWQDE for human IgG (hIgG) affinity chromatography. In this work, effect of ligand density on dynamic binding capacity (DBC) of hIgG on the FYCHWQDE-based resins with ligand densities of 31.1-59.4 μmol/mL and purification of hIgG from human serum were studied. DBC at 10% breakthrough, measured by using 10-fold diluted human serum as feedstock, reached the maximum (27.6±1.3 mg/mL) at 45.3 μmol/mL drained gel and decreased remarkably with increasing flow rate. By using this affinity column with ligand density of 45.3 μmol/mL, hIgG purification from human serum was achieved with high purity (>90%) and recovery yield (82%). The experimental results indicate that the FYCHWQDE-based resin would be a favorable affinity resin for hIgG purification from human serum. | |||
TO cite this article:XUE Aiying,YU Linling,SUN Yan. FYCHWQDE-based affinity chromatography of IgG: Effect of ligand density and purification from human serum[OL].[26 April 2017] http://en.paper.edu.cn/en_releasepaper/content/4728711 |
2. Magnetic targeting effect of methotrexate-loaded Fe3O4-PLLA-PEG-PLLA microspheres prepared in supercritical CO2 | |||
TANG Na,WANG Shibin,CHEN Aizheng | |||
Chemical Engineering 13 December 2016 | |||
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Abstract:The magnetic targeting effect of methotrexate-loaded Fe3O4-poly (L-lactide)-poly (ethylene glycol)-poly (L-lactide) magnetic composite microspheres (MTX-Fe3O4-PLLA-PEG-PLLA MCMs, MMCMs) prepared by co-precipitation (C) and microencapsulation (M) in a process of suspension-enhanced dispersion by supercritical CO2 (SpEDS) was evaluated. The observations of movements and aggregations of MMCMs indicate a good magnetic response in vitro. The results of Prussian blue iron-staining in tumor and the distribution of MTX in S-180-bearing KM mice demonstrate that MMCMs with magnetic field induction could effectively target to tumors. The MTX concentration in tumors treated with free MTX, MMCMs(C) and MMCMs(M) were 8.13±0.46 ng/mL, 138.71±66.22 ng/mL and 282.11±9.36 ng/mL, respectively. This reveals that MMCMs(M) with magnetic field induction possessed a much more remarkable targeting effect than MMCMs(C) and free MTX formulations. This study demonstrates that MMCMs(M) could effectively response to the magnetic induction both in vitro and in vivo, and have potential for application in magnetic targeting therapy of solid tumors. ????? | |||
TO cite this article:TANG Na,WANG Shibin,CHEN Aizheng. Magnetic targeting effect of methotrexate-loaded Fe3O4-PLLA-PEG-PLLA microspheres prepared in supercritical CO2[OL].[13 December 2016] http://en.paper.edu.cn/en_releasepaper/content/4713859 |
3. A Microneedle Mold Fabrication Method | |||
Guo Xin Dong,Wang Qi Lei | |||
Chemical Engineering 24 November 2015 | |||
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Abstract:Microneedle (MN) offers an attractive, painless and minimally invasive approach for transdermal drug delivery. Polymer microneedles are normally fabricated by using the micromolding method employing a MN mold, which is suitable for mass production due to high production efficiency and repeat-using of the mold. Most of the MN molds are prepared by pouring sylgard polymer over a MN master to make an inverse one after curing, which is limited in optimizing or controlling the MN structures and failing to keep the sharpness of MNs. In this work we describe a fabrication method of MN mold with controlled microstructures, which is meaningful for the fabrication of polymer MNs with different geometries. Laser micro-machining method was employed to drill on the surface of PDMS sheets to obtain MN molds. In the fabrication process, the microstructures of MN molds are precisely controlled by changing laser parameters and imported patterns. The MNs prepared from these molds are sharp enough to penetrate the skin. This scalable MN mold fabrication method is helpful for future applications of MNs. | |||
TO cite this article:Guo Xin Dong,Wang Qi Lei. A Microneedle Mold Fabrication Method[OL].[24 November 2015] http://en.paper.edu.cn/en_releasepaper/content/4664002 |
4. Optimization of Fermentation Medium of K.rhizophila.H5401 for Producing (R)-Adrenaline Using Response Surface Methodology | |||
CHEN Bingmei,XU Xiaoping | |||
Chemical Engineering 18 February 2014 | |||
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Abstract:A bacterium strain Kocuria rhizophila.XL11 capable of producing (R)-adrenaline ((R)-epinephrine) with high optical purity (enantiomeric excess > 99%) was firstly isolated. Optimization of the fermentation medium was performed by using response surface methodology. Critical nutrients were initially selected according to a Plackett-Burman design, followed by an application of steepest ascent method to approach the optimal response area. The optimized medium composition for maximum adrenaline production by the mutant strain Kocuria rhizophila.H5401 was obtained based on a three-level three-factor Box-Behnken design, and the optimum concentrations of the critical factors were obtained as follows: glycerol 8.61 goL-1, peptone 7.22 goL-1 and NH4H2PO4 5.65 goL-1. The maximum yield of adrenaline was found to be 61.14%, which is an increase of 25.0% compared to that obtained from the original fermentation medium. | |||
TO cite this article:CHEN Bingmei,XU Xiaoping. Optimization of Fermentation Medium of K.rhizophila.H5401 for Producing (R)-Adrenaline Using Response Surface Methodology[OL].[18 February 2014] http://en.paper.edu.cn/en_releasepaper/content/4583994 |
5. Engineering Bacillus subtilis for acetoin production from glucose and xylose mixtures | |||
CHEN Tao,LIU Weixi,FU Jing,ZHANG BO | |||
Chemical Engineering 23 April 2013 | |||
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Abstract:As a vital flavor compound, acetoin is extensively used in dairy products and drinks industry. In this study, Bacillus subtilis was engineered to metabolize glucose and xylose as substrates for acetoin production. Initially, gene araE from B. subtilis, encoding the xylose transport protein AraE, was placed under the control of the constitutive promoter P43 for over-expression. Batch cultures showed that 10 g/L xylose was depleted completely in 32 hours. Subsequently, genes xylA and xylB from Escherichia coli, encoding xylose isomerase and xylulokinase respectively, were introduced into B. subtilis, and the recombinant turned out to assimilate glucose and xylose without preference. In shake-flask fermentations, 5.5 g/L acetoin with a yield of 0.70 mol (molosugar)-1 was obtained by the optimum strain BSUL13 under microaerobic conditions, which offered a metabolic engineering strategy on engineering microbe as cell factory for the production of high-valued chemicals from renewable resource. | |||
TO cite this article:CHEN Tao,LIU Weixi,FU Jing, et al. Engineering Bacillus subtilis for acetoin production from glucose and xylose mixtures[J]. |
6. Optimization of trace elements using response surface methodology (RSM) for biogas production in dry anaerobic digestion | |||
LI Hongli,CAO Feifei,WANG Yan | |||
Chemical Engineering 25 January 2013 | |||
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Abstract:The effect of trace elements (Fe、Co and Ni) on mesophilic dry anaerobic digestion was investigated in this study. Response surface methodology (RSM), based on a three-level Box-Behnken Design with the Design-Expert Software, was employed in order to obtain the optimal concentrations of trace elements. The experiment results demonstrated that the optimized concentrations of trace elements were 15.0 mg FeoL-1, 1.0 mg CooL-1, 1.2 mg NioL-1, respectively. Under the optimized condition, the maximum accumulated biogas reached 7895.28 mL in mesophilic dry anaerobic digestion, which was consistent with the predicted value by the second-order polynomial model. | |||
TO cite this article:LI Hongli,CAO Feifei,WANG Yan. Optimization of trace elements using response surface methodology (RSM) for biogas production in dry anaerobic digestion[OL].[25 January 2013] http://en.paper.edu.cn/en_releasepaper/content/4518256 |
7. Dissipative Particle Dynamics Simulations on the Mechanism of Micellar Drug Loading Process | |||
GUO Xindong,QIAN Yu,ZHANG Canyang,NIE Shuyu,ZHANG Lijuan | |||
Chemical Engineering 12 July 2012 | |||
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Abstract:The entrapment efficiency of a drug into self-assembled polymeric micelles is commonly found to be extremely low. Drug diffusion into the core of micelles is an important process that affects the micelle loading capacity and efficiency of hydrophobic drugs. Herein, dissipative particle dynamics (DPD) simulations are carried out to study the drug diffusion abilities into the core of micelles after the core-shell structure of micelle is formed, which is the key issue that affects drug laoding efficiencies. Topological structures of drug, hydrophobic block length of polymer, as well as the compatibility between the drug and the hydrophobic block have significant effects on drug loading efficiencies and drug distributions inside micelles. Especially the interaction parameter of 10 rc results in 100% drug loading efficiency and very homogeneous distribution of drug molecules in the core of micelles. We also provide insights into the relationship between drug loading efficiency and micelle stability, which can facilitate the development of stable drug loaded micelles. The present study provides a mechanism study of micellar drug loading on microscale level, which may provide ideas for future experimental preparation of stable drug loaded micelles with high drug loading efficiencies. | |||
TO cite this article:GUO Xindong,QIAN Yu,ZHANG Canyang, et al. Dissipative Particle Dynamics Simulations on the Mechanism of Micellar Drug Loading Process[OL].[12 July 2012] http://en.paper.edu.cn/en_releasepaper/content/4484550 |
8. An oxidoreduction potential shift control strategy for high purity propionic acid production by Propionibacterium freudenreichii CCTCC M207015 with glycerol as sole carbon source | |||
CHEN Fei,FENG Xiaohai,LIANG Jinfeng,XU Hong | |||
Chemical Engineering 04 June 2012 | |||
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Abstract:The effects of oxidoreduction potential (ORP) regulation on the process of propionic acid production by Propionibacterium freudenreichii CCTCC M207015 have been investigated. Potassium ferricyanide and sodium borohydride were to determine as ORP control agents in serum bottle. In batch fermentation, cell growth, propionic acid and by-products distribution were changed with ORP levels in the range of 0 to 160 mV. Based on these analysis results, an ORP-shift control strategy was proposed: At first 156 h, ORP was controlled at 120 mV to obtain higher cell growth rate and propionic acid formation rate, then it was shifted to 80 mV after 156 h to maintain the higher propionic acid formation rate. By applying this ORP-shift control strategy, the optimal parameters were obtained as follows: the propionic acid concentration 45.99 g/L, productivity 0.192 g/L/h, the proportion of propionic acid to total organic acids 92.26% (w/w) and glycerol conversion efficiency 76.65%. The mechanism of ORP regulation was discussed by the ratio of NADH/NAD and ATP levels. The results suggest that it is possible to redistribute metabolic fluxes by the ORP-shift control strategy, and the strategy could provide a simple and efficient tool to realize high purity propionic acid production using glycerol. | |||
TO cite this article:CHEN Fei,FENG Xiaohai,LIANG Jinfeng, et al. An oxidoreduction potential shift control strategy for high purity propionic acid production by Propionibacterium freudenreichii CCTCC M207015 with glycerol as sole carbon source[J]. |
9. Cloning, expression and characterization of thermostable lipase from Geobacillus stearothermophilus DSMZ 1550 | |||
Hu Sheng,Huang Jun,Wu Hong,Mei Lehe | |||
Chemical Engineering 27 March 2012 | |||
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Abstract:A lipase gene of about 1.3 kb was cloned and sequenced from Geobacillus stearothermophilus strain DSMZ 1550. Nucleotide sequence homology analysis showed that the target gene sequence was completely identical to a published sequence (GenBank accession no. AF237623) from Bacillus stearothermophilus P1. The lipase gene was cloned into pET-28c (+) to construct an expression plasmid (pET-28c(+)-lipase), which was transformed into E. coli BL21 for expression. The cultivation parameters of the expression vector harboring strain were optimized to produce the lipase efficiently. The optimal conditions were determined as following: induction at middle stage of exponential growth (OD600 1.09) with 0.5 mM isopropylthio-d-galactoside (IPTG), induction temperature 28℃and post-induction expression for 6 h. Under the above conditions, the specific activity of lipase reached 1.89 IU/mg. Some characteristics of crude recombinant lipase were also investigated. The optimum pH and temperature of the crude lipase were 8.5 and 55℃. The enzyme activity was strongly inhibited by Zn2+, Fe2+, and phenylmethylsulfonyl fluoride (PMSF). | |||
TO cite this article:Hu Sheng,Huang Jun,Wu Hong, et al. Cloning, expression and characterization of thermostable lipase from Geobacillus stearothermophilus DSMZ 1550[OL].[27 March 2012] http://en.paper.edu.cn/en_releasepaper/content/4473260 |
10. Enzymatic regioselective palmitoylation of 5-?uorouridine catalyzed by Lipozyme TL IM in co-solvent mixture | |||
Wu Hong,Hou Xuedan,Zong Minhua | |||
Chemical Engineering 17 January 2011 | |||
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Abstract:A mild, ef?cient and regioselective enzymatic procedure has been successfully conducted for the synthesis of 5'-O-palmitoyl-?uorouridine, a potential prodrug of 5-?uorouridine, from 5-fluorouridine and vinyl palmitate with Lipozyme TL IM in acetone-THF (85/15, v/v) co-solvent mixture. Addition of molecular sieves into the reaction mixture can effectively removed the water, which was proved to cause the hydrolysis of a large amount of acyl donors, thus greatly lowering the acyl donors used. In the presence of molecular sieves, the optimal molar ratio of vinyl palmitate to 5-FUR, enzyme dosage, temperature and shaking rate were 2:1, 15 mg/ml, 40 ℃ and 200 r/min, respectively, under which the initial reaction rate, yield and regioselectivity were 12.3 mM/h, 98.6% and >99%, respectively after 8 hours. Moreover, Lipozyme TL IM displayed a good operational stability and 96.3% of its original activity was maintained after being reused for 10 cycles. | |||
TO cite this article:Wu Hong,Hou Xuedan,Zong Minhua. Enzymatic regioselective palmitoylation of 5-?uorouridine catalyzed by Lipozyme TL IM in co-solvent mixture[OL].[17 January 2011] http://en.paper.edu.cn/en_releasepaper/content/4406894 |
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