Documents disponibles écrits par cet auteur

Fabrication of biocompatible temperature- and pH-responsive magnetic nanoparticles and their reversible agglomeration in aqueous milieu / Liangrong Yang in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8518–8525 Titre : Fabrication of biocompatible temperature- and pH-responsive magnetic nanoparticles and their reversible agglomeration in aqueous milieu Type de document : texte imprimé Auteurs : Liangrong Yang, Auteur ; Chen Guo, Auteur ; Lianwei Jia, Auteur Année de publication : 2010 Article en page(s) : pp. 8518–8525 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticles  Aqueous  milieu Résumé : A novel kind of biocompatible pH- and temperature-responsive magnetic nanoparticle consisting of iron oxide nanoparticles coated with pH-responsive chitosan oligosaccharide and temperature-responsive poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) block copolymer was developed. The particles were characterized by TEM, DLS, VSM, FTIR spectroscopy, and TGA. The results indicated that the self-aggregation of the prepared nanoparticles was not only caused by the thermoinduced self-assembly of the immobilized block copolymers, but also affected by the pH-induced charge property change of the particle surface. The self-assembled behaviors can be readily reversed by adjusting the pH or temperature value. Thus, the attractive properties of reversible and controllable dual-responsive self-assembly might endow the biocompatible magnetic nanoparticles with potential applications in biomedical fields such as DNA delivery, drug targeting, and tissue engineering. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100587e [article] Fabrication of biocompatible temperature- and pH-responsive magnetic nanoparticles and their reversible agglomeration in aqueous milieu [texte imprimé] / Liangrong Yang, Auteur ; Chen Guo, Auteur ; Lianwei Jia, Auteur . - 2010 . - pp. 8518–8525. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8518–8525 Mots-clés : Nanoparticles  Aqueous  milieu Résumé : A novel kind of biocompatible pH- and temperature-responsive magnetic nanoparticle consisting of iron oxide nanoparticles coated with pH-responsive chitosan oligosaccharide and temperature-responsive poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) block copolymer was developed. The particles were characterized by TEM, DLS, VSM, FTIR spectroscopy, and TGA. The results indicated that the self-aggregation of the prepared nanoparticles was not only caused by the thermoinduced self-assembly of the immobilized block copolymers, but also affected by the pH-induced charge property change of the particle surface. The self-assembled behaviors can be readily reversed by adjusting the pH or temperature value. Thus, the attractive properties of reversible and controllable dual-responsive self-assembly might endow the biocompatible magnetic nanoparticles with potential applications in biomedical fields such as DNA delivery, drug targeting, and tissue engineering. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100587e

Immobilizing penicillin G acylase using silica-supported ionic liquids / Huacong Zhou in Industrial & engineering chemistry research, Vol. 51 N° 40 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13173–13181 Titre : Immobilizing penicillin G acylase using silica-supported ionic liquids : The effects of ionic liquid loadings Type de document : texte imprimé Auteurs : Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur Année de publication : 2012 Article en page(s) : pp. 13173–13181 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Loading  Ionic  liquid Résumé : The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol-gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol-gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol-gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol-gel 2 sample. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451467 [article] Immobilizing penicillin G acylase using silica-supported ionic liquids : The effects of ionic liquid loadings [texte imprimé] / Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur . - 2012 . - pp. 13173–13181. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13173–13181 Mots-clés : Loading  Ionic  liquid Résumé : The supported ionic liquids (SILs) were prepared via immobilizing silane-functionalized ionic liquids (IL) onto the monodispersive silica nanoparticles, and the composite material was then applied in the immobilization of penicillin G acylase (PGA, EC 3.5.1.11), an important industrial enzyme for the production of semisynthetic antibiotics. This was a novel approach of immobilizing PGA proposed in our previous report, in which we had studied the effects of IL types on the performance of this novel support. Here, we focused on the effects of IL loading on the properties of the SILs and their performance in PGA immobilization. The effects of silica sizes and routes of preparing SILs (the solvent route and the sol-gel route) on IL loading were investigated. The results showed that (1) the IL loading could be tuned efficiently by changing the silica sizes. (2) As compared with the solvent route, the sol-gel route is more simple, time-saving, and ecofriendly in operation. What's more, it has a higher IL loading. Among the factors affecting the IL loading, the reaction time was the most feasible factor to control to tune the IL loading, as compared with the temperature and the dosage of ILs. (3) With the increase of IL loading, the surface ζ-potential of silicas changed from negative to positive, and the isoelectronic point (IEP) increased accordingly, which caused the decrease of the protein loading but the increase of apparent and specific activity. A reusability experiment showed that the sol-gel 1 sample maintained approximately 55% of the initial activity even after 10 consecutive operation cycles under the experimental conditions. This activity was 3.7 times higher than that of the sol-gel 2 sample. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451467

Improving the stability of immobilized penicillin G acylase via the modification of supports with ionic liquids / Huacong Zhou in Industrial & engineering chemistry research, Vol. 51 N° 12 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4582–4590 Titre : Improving the stability of immobilized penicillin G acylase via the modification of supports with ionic liquids Type de document : texte imprimé Auteurs : Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur Année de publication : 2012 Article en page(s) : pp. 4582–4590 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic  liquids  Nanoparticles Résumé : With the aim of improving the stability of penicillin G acylase (PGA), functional ionic liquids (ILs) were used to modify the surface chemistry of the supports on which they were physically adsorbed. Four kinds of ILs—specifically, 1-methyl-3-(triethoxysilylpropyl)-imidazolium salts, with Cl–, BF4–, PF6–, and Tf2N– as the anions (IL-Cl–, BF4–, PF6–, and Tf2N–, respectively)—were used to tune the hydrophilic or hydrophobic properties of the ILs. The synthesized ILs were first immobilized on magnetic silica nanoparticles (Fe3O4/SiO2), and the composite material (Fe3O4/SiO2–IL) was then applied to immobilize PGA via physical adsorption. The amount of protein loading, the specific activity, the immobilization yield, and the stability of immobilized PGA were investigated to evaluate the effects of the ILs on the PGA immobilization. The results showed that PGA immobilized on Fe3O4/SiO2–ILs was more stable than that immobilized on Fe3O4/SiO2 with no IL modification. Among the four kinds of ILs tested, the hydrophilic ILs (IL-Cl–, and IL-BF4–) were superior to the hydrophobic ones (IL-PF6–, and IL-Tf2N–) for PGA immobilization. The reusability of the immobilized PGA on Fe3O4/SiO2–IL (BF4–) was evaluated; a high residual activity (70% of the initial activity) was observed after 9 consecutive operation cycles under the experimental conditions. This activity was 1.8 times higher than that of immobilized PGA on naked Fe3O4/SiO2 (40%). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202745c [article] Improving the stability of immobilized penicillin G acylase via the modification of supports with ionic liquids [texte imprimé] / Huacong Zhou, Auteur ; Liangrong Yang, Auteur ; Wei Li, Auteur . - 2012 . - pp. 4582–4590. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 12 (Mars 2012) . - pp. 4582–4590 Mots-clés : Ionic  liquids  Nanoparticles Résumé : With the aim of improving the stability of penicillin G acylase (PGA), functional ionic liquids (ILs) were used to modify the surface chemistry of the supports on which they were physically adsorbed. Four kinds of ILs—specifically, 1-methyl-3-(triethoxysilylpropyl)-imidazolium salts, with Cl–, BF4–, PF6–, and Tf2N– as the anions (IL-Cl–, BF4–, PF6–, and Tf2N–, respectively)—were used to tune the hydrophilic or hydrophobic properties of the ILs. The synthesized ILs were first immobilized on magnetic silica nanoparticles (Fe3O4/SiO2), and the composite material (Fe3O4/SiO2–IL) was then applied to immobilize PGA via physical adsorption. The amount of protein loading, the specific activity, the immobilization yield, and the stability of immobilized PGA were investigated to evaluate the effects of the ILs on the PGA immobilization. The results showed that PGA immobilized on Fe3O4/SiO2–ILs was more stable than that immobilized on Fe3O4/SiO2 with no IL modification. Among the four kinds of ILs tested, the hydrophilic ILs (IL-Cl–, and IL-BF4–) were superior to the hydrophobic ones (IL-PF6–, and IL-Tf2N–) for PGA immobilization. The reusability of the immobilized PGA on Fe3O4/SiO2–IL (BF4–) was evaluated; a high residual activity (70% of the initial activity) was observed after 9 consecutive operation cycles under the experimental conditions. This activity was 1.8 times higher than that of immobilized PGA on naked Fe3O4/SiO2 (40%). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202745c

PH-sensitive magnetic ion exchanger for protein separation / Liangrong Yang in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 944–950 Titre : PH-sensitive magnetic ion exchanger for protein separation Type de document : texte imprimé Auteurs : Liangrong Yang, Auteur ; Chen, Guo, Auteur ; Shu Chen, Auteur ; Feng Wang, Auteur ; Jing Wang, Auteur ; Zhentao An, Auteur Année de publication : 2009 Article en page(s) : p. 944–950 Note générale : chimical engineering Langues : Anglais (eng) Mots-clés : pH-sensitive Résumé : A pH-sensitive magnetic ion exchanger was synthesized by binding carboxymethylated chitosan (CMCH) covalently on the surface of Fe3O4 nanoparticles. The diameter for magnetic particles observed at 25 °C was 15 nm. The ion exchanger was superparamagnetic with a saturation magnetization of 64.21 emu/g and an isoelectric point (pI) of 5.75. In a model system, the laccase adsorption capacity reached equilibrium within 15 min (pH 5). The adsorption process followed the Langmuir adsorption isotherm, and the maximum equilibrium adsorption capacity was calculated to be 198.81 mg/g. The laccase can be completely desorbed at pH 8. About 97% laccase can be effectively desorbed from the surface of particles within 15 min. Moreover, the specific activity of the laccase remained constant during the adsorption and desorption process. Finally, the pH-sensitive magnetic ion exchanger was used for separation of laccase directly from culture supernatant, and nearly pure laccase was isolated by a single step with an activity recovery rate of 63%. [article] PH-sensitive magnetic ion exchanger for protein separation [texte imprimé] / Liangrong Yang, Auteur ; Chen, Guo, Auteur ; Shu Chen, Auteur ; Feng Wang, Auteur ; Jing Wang, Auteur ; Zhentao An, Auteur . - 2009 . - p. 944–950. chimical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 944–950 Mots-clés : pH-sensitive Résumé : A pH-sensitive magnetic ion exchanger was synthesized by binding carboxymethylated chitosan (CMCH) covalently on the surface of Fe3O4 nanoparticles. The diameter for magnetic particles observed at 25 °C was 15 nm. The ion exchanger was superparamagnetic with a saturation magnetization of 64.21 emu/g and an isoelectric point (pI) of 5.75. In a model system, the laccase adsorption capacity reached equilibrium within 15 min (pH 5). The adsorption process followed the Langmuir adsorption isotherm, and the maximum equilibrium adsorption capacity was calculated to be 198.81 mg/g. The laccase can be completely desorbed at pH 8. About 97% laccase can be effectively desorbed from the surface of particles within 15 min. Moreover, the specific activity of the laccase remained constant during the adsorption and desorption process. Finally, the pH-sensitive magnetic ion exchanger was used for separation of laccase directly from culture supernatant, and nearly pure laccase was isolated by a single step with an activity recovery rate of 63%.

Three - liquid - phase extraction / Keng Xie in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12767-12773 Titre : Three - liquid - phase extraction : a new approach for simultaneous enrichment and separation of Cr(III) and Cr(VI) Type de document : texte imprimé Auteurs : Keng Xie, Auteur ; Kun Huang, Auteur ; Liangrong Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 12767-12773 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid  phase Résumé : A novel and simple three-liquid-phase extraction (TLPE) approach was developed for the simultaneous removal and separation of Cr(III) and Cr(VI) from aqueous solutions. The proposed three-liquid-phase system (TLPS) consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), poly(ethylene glycol) (PEG) with a molecularweight of 2000, and (NH4)2SO4. The effects of various factors including the aqueous solution pH, amounts of (NH4)2SO4 and PEG, initial chromium amount, D2EHPA concentration, phase-mixing time, and diluent on the three-phase partitioning behavior of Cr(III) and Cr(VI) were evaluated. The distribution behavior of the two oxidation states of chromium was found to be highly pH-dependent. Cr(III) preferred the D2EHPA-rich top phase through a cation-exchange reaction, whereas Cr(VI) was enriched in the PEG-rich middle phase through ion-pair formation. By appropriate selection of the extraction conditions, nearly all of the Cr(III) was extracted into the D2EHPA top phase, and more than 90% of the Cr(VI) was transferred into the PEG-rich middle phase within 5 min. The present work highlights the possibility of using the TLPE approach for the extraction and separation of two different oxidation states of metal ions, such as Cr(III) and Cr(VI), in a single extraction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745751 [article] Three - liquid - phase extraction : a new approach for simultaneous enrichment and separation of Cr(III) and Cr(VI) [texte imprimé] / Keng Xie, Auteur ; Kun Huang, Auteur ; Liangrong Yang, Auteur . - 2012 . - pp. 12767-12773. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12767-12773 Mots-clés : Liquid  phase Résumé : A novel and simple three-liquid-phase extraction (TLPE) approach was developed for the simultaneous removal and separation of Cr(III) and Cr(VI) from aqueous solutions. The proposed three-liquid-phase system (TLPS) consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), poly(ethylene glycol) (PEG) with a molecularweight of 2000, and (NH4)2SO4. The effects of various factors including the aqueous solution pH, amounts of (NH4)2SO4 and PEG, initial chromium amount, D2EHPA concentration, phase-mixing time, and diluent on the three-phase partitioning behavior of Cr(III) and Cr(VI) were evaluated. The distribution behavior of the two oxidation states of chromium was found to be highly pH-dependent. Cr(III) preferred the D2EHPA-rich top phase through a cation-exchange reaction, whereas Cr(VI) was enriched in the PEG-rich middle phase through ion-pair formation. By appropriate selection of the extraction conditions, nearly all of the Cr(III) was extracted into the D2EHPA top phase, and more than 90% of the Cr(VI) was transferred into the PEG-rich middle phase within 5 min. The present work highlights the possibility of using the TLPE approach for the extraction and separation of two different oxidation states of metal ions, such as Cr(III) and Cr(VI), in a single extraction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745751