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Preparation of copolymer-grafted mixed-mode resins for immunoglobulin G adsorption

Shenggang Chen, Tao Liu, Ruiqi Yang, Dongqiang Lin, Shanjing Yao

《化学科学与工程前沿(英文)》 2019年 第13卷 第1期   页码 70-79 doi: 10.1007/s11705-018-1745-4

摘要: The mixed-mode resins for protein adsorption have been prepared by a novel strategy, copolymer grafting. Specially, the copolymer-grafted resins CG-M-A with two functional groups, 5-amino-benzimidazole (ABI) and methacryloxyethyltrimethyl ammonium chloride (METAC), have been prepared through surface-initiated activator generated by electron transfer for atom transfer radical polymerization of METAC and glycidyl methacrylate (GMA), followed by a ring-open reaction to introduce ABI. The charge and hydrophobicity of CG-M-A resins could be controlled by manipulating the addition of METAC and GMA/ABI. Besides, METAC and ABI provided positive effects together in both protein adsorption and elution: dynamic binding capacity of human Immunoglobulin G (hIgG) onto CG-M-A resin with the highest ligand ratio of METAC to ABI is 46.8 mg·g at pH 9 and the elution recovery of hIgG is 97.0% at pH 5. The separation experiment showed that purity and recovery of monoclonal antibody from cell culture supernatant are 96.0% and 86.5%, respectively, indicating that copolymer-grafted mixed-mode resins could be used for antibody purification.

关键词: atom transfer radical polymerization     copolymer-grafting     mixed-mode resin     protein adsorption    

Fabrication of high-capacity cation-exchangers for protein adsorption: Comparison of grafting-from andgrafting-to approaches

Ming Zhao, Run Liu, Jian Luo, Yan Sun, Qinghong Shi

《化学科学与工程前沿(英文)》 2019年 第13卷 第1期   页码 120-132 doi: 10.1007/s11705-018-1730-y

摘要: In this work, we have synthesized two polymer-grafted cation exchangers: one via the grafting-from approach, in which sulfopropyl methacrylate (SPM) is grafted through atom transfer radical polymerization onto Sepharose FF (the thus resulting exchanger is referred as Sep- -SPM), and another via the grafting-to approach, in which the polymer of SPM is directly coupled onto Sepharose FF (the thus resulting exchanger is called as Sep- SPM). Protein adsorption on these two cation exchangers have been also investigated. At the same ligand density, Sep- -SPM has a larger accessible pore radius and a smaller depth of polymer layer than Sep- SPM, due to the controllable introduction of polymer chains with the regular distribution of the ligand. Therefore, high-capacity adsorption of lysozyme and -globulin could be achieved simultaneously in Sep- -SPM with an ionic capacity (IC) of 308 mmol·L . However, Sep- SPM has an irregular chain distribution and different architecture of polymer layer, which lead to more serious repulsive interaction to proteins, and thus Sep- SPM has a lower adsorption capacity for -globulin than Sep- -SPM with the similar IC. Moreover, the results from protein uptake experiments indicate that the facilitated transport of adsorbed -globulin occurs only in Sep- SPM and depends on the architecture of polymer layers. Our research provides a clear clue for the development of high-performance protein chromatography.

关键词: polymer-grafted ionic exchanger     grafting technique     protein adsorption     atom transfer radical polymerization     γ-globulin    

Liver cell therapies: cellular sources and grafting strategies

《医学前沿(英文)》 2023年 第17卷 第3期   页码 432-457 doi: 10.1007/s11684-023-1002-1

摘要: The liver has a complex cellular composition and a remarkable regenerative capacity. The primary cell types in the liver are two parenchymal cell populations, hepatocytes and cholangiocytes, that perform most of the functions of the liver and that are helped through interactions with non-parenchymal cell types comprising stellate cells, endothelia and various hemopoietic cell populations. The regulation of the cells in the liver is mediated by an insoluble complex of proteins and carbohydrates, the extracellular matrix, working synergistically with soluble paracrine and systemic signals. In recent years, with the rapid development of genetic sequencing technologies, research on the liver’s cellular composition and its regulatory mechanisms during various conditions has been extensively explored. Meanwhile breakthroughs in strategies for cell transplantation are enabling a future in which there can be a rescue of patients with end-stage liver diseases, offering potential solutions to the chronic shortage of livers and alternatives to liver transplantation. This review will focus on the cellular mechanisms of liver homeostasis and how to select ideal sources of cells to be transplanted to achieve liver regeneration and repair. Recent advances are summarized for promoting the treatment of end-stage liver diseases by forms of cell transplantation that now include grafting strategies.

关键词: liver regeneration     hepatocytes     cholangiocytes     stem cells     organoids     regulatory mechanisms     transplantation/grafting strategies    

PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized

Shuai Wang, Tong Li, Chen Chen, Baicang Liu, John C. Crittenden

《环境科学与工程前沿(英文)》 2018年 第12卷 第2期 doi: 10.1007/s11783-017-0980-0

摘要: Polyvinylidene fluoride grafted with poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) was synthesized using atomic transfer radical polymerization (ATRP) at different reaction times (9 h, 19 h, and 29 h). The corresponding conversion rates were 10%, 20% and 30%, respectively. PVDF was blended with the copolymer mixture containing PVDF-g-PEGMA, solvent and residual PEGMA under different reaction times. In this study, we explored the effect of the copolymer mixture additives with different synthesis times on cast membrane performance. Increasing the reaction time of PVDF-g-PEGMA causes more PVDF-g-PEGMA and less residual PEGMA to be found in the casting solution. Incremental PVDF-g-PEGMA can dramatically increase the viscosity of the casting solution. An overly high viscosity led to a delayed phase inversion, thus hindering PEGMA segments in PVDF-g-PEGMA from migrating to the membrane surface. However, more residual PEGMA contributed to helping more PEGMA segments migrate to the membrane surface. The pure water fluxes of the blended membrane with reaction times of 9 h, 19 h, and 29 h are 5445 L·m ·h , 1068 L·m ·h and 1179 L·m ·h , respectively, at 0.07 MPa. Delayed phase inversion can form smaller surface pore size distributions, thus decreasing the water flux for the membranes with PVDF-g-PEGMA at 19 h and 29 h. Therefore, we can control the membrane pore size distribution by decreasing the reaction time of PVDF-g-PEGMA to obtain a better flux performance. The membrane with PVDF-g-PEGMA at 19 h exhibits the best foulant rejection and cleaning recovery due to its narrow pore size distribution and high surface oxygen content.

关键词: Polyvinylidene fluoride ultrafiltration membrane     Amphiphilic copolymer     Blended modification     High flux     Atomic transfer radical polymerization    

Synthesis of a new iron (III) porphyrin acrylate-styrene copolymer and its catalysis for hydroxylation

YU Hancheng, LI Xixian, HUANG Jinwang, JI Liangnian, CHEN Xianli

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 65-67 doi: 10.1007/s11705-007-0013-9

摘要: A new iron (III) porphyrin acrylate-styrene copolymer, P[(PorFe)A-S], was synthesized by the reaction of iron (III) porphyrin acrylate with styrene and characterized by UV-Vis, Infrared spectra (IR), inductively coupled plasma-atomic emission spectrometry (ICP) and molecular weight determination. Its catalytic activity in the hydroxylation of cyclohexane for model cytochrome P450 in the P[(PorFe)A-S]-O ascrobate-thiosalicylic acid system has been studied. It was found that the P[(PorFe)A-S] has a higher catalytic activity than non-supported iron (III) porphyrin and its high catalytic activity remained in reuse. The catalytic activity of P[(PorFe)A-S] was discussed in the view of the microenvironment of iron (III) porphyrin. It is proposed that the atalytic activity of the P[(PorFe)A-S] may be further enhanced by construction of a homophase catalytic system containing the iron (III) porphyrin acrylate-styrene copolymer.

关键词: plasma-atomic emission     UV-Vis     weight determination     acrylate-styrene copolymer     styrene    

Trihydrazinotriazine-grafting Fe

Jamal Rahimi, Seyedeh Shadi Mirmohammadi, Ali Maleki

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 1008-1020 doi: 10.1007/s11705-020-1996-8

摘要: This study focuses on the synthesis and characterization of a novel magnetic nanocomposite 2,4,6-trihydrazino-1,3,5-triazine (THDT)-functionalized with silica-coated iron oxide magnetic nanoparticles (MNPs). This nanocomposite has porous morphology decorated with the spherical MNPs. Through co-precipitation of iron salts, MNPs were obtained. The prepared THDT was placed on the chlorine surface-modified MNPs. The present environment-friendly nanocatalyst intensely accelerated the synthesis of highly functionalized tetrahydrobenzo[ ]pyran derivatives as well as reduced the reaction times and increased yields of the products.

关键词: trihydrazino-triazine     porous     magnetic nanocatalyst     green chemistry     tetrahydrobenzo[b]pyrans    

Thermoresponsive block copolymer supported Pt nanocatalysts for base-free aerobic oxidation of 5-hydroxymethyl

《化学科学与工程前沿(英文)》 2021年 第15卷 第6期   页码 1514-1523 doi: 10.1007/s11705-021-2092-4

摘要: A base-free catalytic system for the aerobic oxidation of 5-hydroxymethyl-2-furfural was exploited by using Pt nanoparticles immobilized onto a thermoresponsive poly(acrylamide-co-acrylonitrile)-b-poly(N-vinylimidazole) block copolymer, with an upper critical solution temperature of about 45 °C. The Pt nanocatalysts were well-dispersed and highly active for the base-free oxidation of 5-hydroxymethyl-2-furfural by molecular oxygen in water, affording high yields of 2,5-furandicarboxylic acid (up to>99.9%). The imidazole groups in the block copolymer were conducive to the improvement of catalytic performance. Moreover, the catalysts could be easily separated and recovered based on their thermosensitivity by cooling the reaction system below the upper critical solution temperature. Good stability and reusability were observed over these copolymer-immobilized catalysts with no obvious decrease in catalytic activity in the five consecutive cycles.

关键词: aerobic oxidation     base-free     5-hydroxymethyl-2-furfural     Pt nanoparticle     thermoresponsive block copolymer    

SinoSCORE: a logistically derived additive prediction model for post-coronary artery bypass grafting

null

《医学前沿(英文)》 2013年 第7卷 第4期   页码 477-485 doi: 10.1007/s11684-013-0284-0

摘要:

This study aims to construct a logistically derived additive score for predicting in-hospital mortality risk in Chinese patients undergoing coronary artery bypass surgery (CABG). Data from 9839 consecutive CABG patients in 43 Chinese centers were collected between 2007 and 2008 from the Chinese Coronary Artery Bypass Grafting Registry. This database was randomly divided into developmental and validation subsets (9:1). The data in the developmental dataset were used to develop the model using logistic regression. Calibration and discrimination characteristics were assessed using the validation dataset. Thresholds were defined for each model to distinguish different risk groups. After excluding 275 patients with incomplete information, the overall mortality rate of the remaining 9564 patients was 2.5%. The SinoSCORE model was constructed based on 11 variables: age, preoperative NYHA stage III or IV, chronic renal failure, extracardiac arteriopathy, chronic obstructive pulmonary disease, preoperative atrial fibrillation or flutter (within 2βweeks), left ventricular ejection fraction, other elective surgery, combined valve procedures, preoperative critical state, and BMI. In the developmental dataset, calibration using a Hosmer-Lemeshow (HL) test was at =β0.44 and discrimination based on the area under the receiver operating characteristic curve (ROC) was 0.80. In the validation dataset, the HL test was at =β0.34 and the area under the ROC (AUC) was 0.78. A logistically derived additive model for predicting in-hospital mortality among Chinese patients undergoing CABG was developed based on the most up-to-date multi-center data from China.

关键词: coronary artery bypass grafting     risk stratification     in-hospital mortality    

Effect of styrene-butadiene-styrene copolymer on the aging resistance of asphalt: An atomistic understanding

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1261-1276 doi: 10.1007/s11709-021-0761-5

摘要: To reveal the potential influence of styrene-butadiene-styrene (SBS) polymer modification on the anti-aging performance of asphalt, and its mechanism, we explored the aging characteristics of base asphalt and SBS-modified asphalt by reaction force field (ReaxFF) and classical molecular dynamics simulations. The results illustrate that the SBS asphalt is more susceptible to oxidative aging than the base asphalt under oxygen-deficient conditions due to the presence of unsaturated C=C bonds in the SBS polymer. In the case of sufficient oxygen, the SBS polymer inhibits the oxidation of asphalt by restraining the diffusion of asphalt molecules. Compared with the base asphalt, the SBS asphalt exhibits a higher degree of oxidation at the early stage of pavement service and a lower degree of oxidation in the long run. In addition, SBS polymer degrades into small blocks during aging, thus counteracting the hardening of aged asphalt and partially restoring its low-temperature cracking resistance.

关键词: SBS asphalt     oxidative aging     asphalt hardening     ReaxFF     molecular dynamics    

Solution properties and self-association of multi-blocks like copolymer P(AM/AA) prepared by template

ZHANG Yuxi, WU Feipeng, LI Miaozhen, WANG Erjian

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 68-71 doi: 10.1007/s11705-007-0014-8

摘要: The association and properties of multi-block like copolymers (TP) of acrylamide (AM) and acrylic acid (AA) prepared by template copolymerization in aqueous solution were studied. The results showed that the copolymers of this type exhibited a significant structure effect compared with that of similar random copolymers (CP) obtained by copolymerization in the absence of template. Decreasing the value of pH or adding Ca ion to the copolymer solution will make phase separation occur. The TEM images demonstrated that the phase separation caused by Ca ion was due to the formation of extensively intermolecular cross-linking. With the increase of the pH value of copolymer solution, the changes of the solution viscosity was similar with that of homopolyacrylic acid, which originally increased and then decreased. But the increase range of template copolymer was higher than that of homopolyacrylic acid. TEM images indicated that at the maximal viscosity the copolymer obtained in the presence of template formed coiled aggregates.

关键词: aqueous solution     homopolyacrylic     copolymer solution     significant structure     presence    

Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1470-1483 doi: 10.1007/s11705-023-2329-5

摘要: In this paper, graphene oxide quantum dots with amino groups (NH2-GOQDs) were tailored to the surface of a thin-film composite (TFC) membrane surface for optimizing forward osmosis (FO) membrane performance using the amide coupling reaction. The results jointly demonstrated hydrophilicity and surface roughness of the membrane enhanced after grafting NH2-GOQDs, leading to the optimized affinity and the contact area between the membrane and water molecules. Therefore, grafting of the membrane with a concentration of 100 ppm (TFC-100) exhibited excellent permeability performance (58.32 L·m–2·h–1) compared with TFC membrane (16.94 L·m–2·h–1). In the evaluation of static antibacterial properties of membranes, TFC-100 membrane destroyed the cell morphology of Escherichia coli (E. coli) and reduced the degree of bacterial adsorption. In the dynamic biofouling experiment, TFC-100 membrane showed a lower flux decline than TFC membrane. After the physical cleaning, the flux of TFC-100 membrane could recover to 96% of the initial flux, which was notably better than that of TFC membrane (63%). Additionally, the extended Derjaguin–Landau–Verwey–Overbeek analysis of the affinity between pollutants and membrane surface verified that NH2-GOQDs alleviates E. coli contamination of membrane. This work highlights the potential applications of NH2-GOQDs for optimizing permeability and biofouling mitigation of FO membranes.

关键词: forward osmosis membrane     graphene oxide quantum dots     graft modification     anti-fouling membrane     XDLVO theory    

Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 407-411 doi: 10.1007/s11705-008-0064-6

摘要: Well-defined comb-like branched polymers having one branch in each repeating unit have been successfully synthesized by the coupling reaction of living polystyrene (PS) and polyisoprene (PI) anions with 1, 1-diphenylethenyl (DPE) groups along PS backbone prepared via atom transfer radical polymerization (ATRP) of 4-vinylbenzyloxy benzophenone (Sc) followed by Wittig reaction. The resulting comb-like branched polymers were characterized by IR, H-NMR, gel permeation chromatography (GPC) and static light scattering (SLS) in detail. The effect of living chains and DPE group molar ratio on grafting efficiency was discussed. The results show the coupling reaction of living chains and DPE groups was highly effective, and the coupling efficiency can be controlled via the feed molar ratios of living chains and DPE groups. Moreover, the effect of molecular weights of backbone (PSe) and PSLi or PILi on grafting efficiency was also discussed. The results show that when excess living polymers were used, the almost quantitative grafting efficiency could be achieved.

关键词: grafting efficiency     polyisoprene     quantitative grafting     effective     molecular    

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

《化学科学与工程前沿(英文)》 2017年 第11卷 第3期   页码 440-447 doi: 10.1007/s11705-017-1626-2

摘要: Isothermal-isobaric molecular dynamics simulation was used to study the diffusion mechanism of water in polyurethane- -poly( -isopropyl acrylamide) (PU- -PNIPAm) with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 K and 450 K. Here, the experimental glass transition temperature ( ) of PU is 243 K while that of PNIPAm is 383 K. Different amounts of water up to 15 wt-% were added to PU- -PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures (250 K and 390 K) of PU- -PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures (i.e., following the free volume model of Fujita). It suggested that water diffusion in PU- -PNIPAm depends only on its fractional free volume despite the free volume inhomogeneity. It is noted that at 298 K, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2–0.4 nm in PU- -PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词: molecular dynamics simulation     amphiphilic block copolymer     free volume     water diffusivity     fujita model    

Morphologies of diblock copolymer confined in a slit with patterned surfaces studied by dissipative particle

FENG Jian, HUANG Yongmin, LIU Honglai, HU Ying

《化学科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 132-139 doi: 10.1007/s11705-007-0025-5

摘要: Diblock copolymers with ordered mesophase structures have been used as templates for nano-fabrication. Unfortunately, the ordered structure only exists at micrometer-scale areas, which precludes its use in many advanced applications. To overcome this disadvantage, the diblock copolymer confined in a restricted system with a patterned surface is proved to be an effective means to prohibit the formation of defects and obtain perfect ordered domains. In this work, the morphologies of a thin film of diblock copolymer confined between patterned and neutral surfaces were studied by dissipative particle dynamics. It is shown that the morphology of the symmetric diblock copolymer is affected by the ratio of the pattern period on the surface to the lamellar period of the symmetric diblock copolymer and by the repulsion parameters between blocks and wall particles. To eliminate the defects in the lamellar phase, the pattern period on the surface must match the lamellar period. The difference in the interface energy of different compartments of the pattern should increase with increasing film thickness. The pattern period on the surface has a scaling relationship with the chain length, which is the same as that between the lamellar period and the chain length. The lamellar period is also affected by the polydispersity of the symmetric diblock copolymer. The total period is the average of the period of each component multiplied by the weight of its volume ratio. The morphologies of asymmetric diblock copolymers are also affected by the pattern on the surface, especially when the matching period of the asymmetric diblock copolymer is equal to the pattern period, which is approximately equal to the lamellar period of a symmetric diblock copolymer with the same chain length.

关键词: weight     nano-fabrication     morphology     matching     dissipative particle    

Highly selective detection of copper(II) by a “ligand-free” conjugated copolymer in nucleophilic solvents

Weixing Deng, Pengfei Sun, Quli Fan, Lei Zhang, Tsuyoshi Minami

《化学科学与工程前沿(英文)》 2020年 第14卷 第1期   页码 105-111 doi: 10.1007/s11705-019-1791-6

摘要: The synthesis of -cyclohexyl carbamate-attached fluorene- -phenylene copolymer (PFPNCC) and the use of PFPNCC as a “ligand-free” fluorescent chemosensor for Cu(II) are described. Addition of Cu(II) can efficiently quench the fluorescence of PFPNCC in nucleophilic solvents such as DMF and DMSO, but not in low nucleophilic solvents such as 1,4-dioxane and THF. Ultraviolet-visible spectra of the mixture of the conjugated polymer and Cu(II) indicate the presence of a reduced Cu(I) ion in the solution. Furthermore, fluorescence recovery of PFPNCC observed at low temperature suggests that the quenching and reducing mechanism is most probably due to a photo-induced electron transfer from excited PFPNCC to Cu(II). Our findings provide a novel strategy for highly selective conjugated polymer-based chemosensors for various target analytes, albeit “ligand-free”.

关键词: ligand-free     fluorescent chemosensor     copper     photo-induced electron transfer    

标题 作者 时间 类型 操作

Preparation of copolymer-grafted mixed-mode resins for immunoglobulin G adsorption

Shenggang Chen, Tao Liu, Ruiqi Yang, Dongqiang Lin, Shanjing Yao

期刊论文

Fabrication of high-capacity cation-exchangers for protein adsorption: Comparison of grafting-from andgrafting-to approaches

Ming Zhao, Run Liu, Jian Luo, Yan Sun, Qinghong Shi

期刊论文

Liver cell therapies: cellular sources and grafting strategies

期刊论文

PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized

Shuai Wang, Tong Li, Chen Chen, Baicang Liu, John C. Crittenden

期刊论文

Synthesis of a new iron (III) porphyrin acrylate-styrene copolymer and its catalysis for hydroxylation

YU Hancheng, LI Xixian, HUANG Jinwang, JI Liangnian, CHEN Xianli

期刊论文

Trihydrazinotriazine-grafting Fe

Jamal Rahimi, Seyedeh Shadi Mirmohammadi, Ali Maleki

期刊论文

Thermoresponsive block copolymer supported Pt nanocatalysts for base-free aerobic oxidation of 5-hydroxymethyl

期刊论文

SinoSCORE: a logistically derived additive prediction model for post-coronary artery bypass grafting

null

期刊论文

Effect of styrene-butadiene-styrene copolymer on the aging resistance of asphalt: An atomistic understanding

期刊论文

Solution properties and self-association of multi-blocks like copolymer P(AM/AA) prepared by template

ZHANG Yuxi, WU Feipeng, LI Miaozhen, WANG Erjian

期刊论文

Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum

期刊论文

Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

期刊论文

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

期刊论文

Morphologies of diblock copolymer confined in a slit with patterned surfaces studied by dissipative particle

FENG Jian, HUANG Yongmin, LIU Honglai, HU Ying

期刊论文

Highly selective detection of copper(II) by a “ligand-free” conjugated copolymer in nucleophilic solvents

Weixing Deng, Pengfei Sun, Quli Fan, Lei Zhang, Tsuyoshi Minami

期刊论文