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1.
J Sep Sci ; 39(16): 3130-6, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27465269

RESUMEN

Hydrophobic charge-induction chromatography is a new technology for antibody purification. To improve antibody adsorption capacity of hydrophobic charge-induction resins, new poly(glycidyl methacrylate)-grafted hydrophobic charge-induction resins with 5-aminobenzimidazole as a functional ligand were prepared. Adsorption isotherms, kinetics, and dynamic binding behaviors of the poly(glycidyl methacrylate)-grafted resins prepared were investigated using human immunoglobulin G as a model protein, and the effects of ligand density were discussed. At the moderate ligand density of 330 µmol/g, the saturated adsorption capacity and equilibrium constant reached the maximum of 140 mg/g and 25 mL/mg, respectively, which were both much higher than that of non-grafted resin with same ligand. In addition, effective pore diffusivity and dynamic binding capacity of human immunoglobulin G onto the poly(glycidyl methacrylate)-grafted resins also reached the maximum at the moderate ligand density of 330 µmol/g. Dynamic binding capacity at 10% breakthrough was as high as 76.3 mg/g when the linear velocity was 300 cm/h. The results indicated that the suitable polymer grafting combined with the control of ligand density would be a powerful tool to improve protein adsorption of resins, and new poly(glycidyl methacrylate)-grafted hydrophobic charge-induction resins have a promising potential for antibody purification applications.


Asunto(s)
Cromatografía/instrumentación , Inmunoglobulina G/aislamiento & purificación , Ácidos Polimetacrílicos/química , Sefarosa/química , Adsorción , Bencimidazoles/química , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Inmunoglobulina G/química , Cinética , Ligandos , Resinas Sintéticas/química
2.
J Sep Sci ; 37(4): 447-53, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24318171

RESUMEN

In this study, an aqueous two-phase system (ATPS) with PEG and hydroxypropyl starch (HPS) was used to separate monoclonal antibody (mAb) from Chinese hamster ovary cell culture supernatant. The phase diagram of the PEG/HPS ATPS was determined, and the effects of NaCl addition were investigated. The results showed that NaCl addition could lead to a shift of the binodal curve and that phase separation would occur at higher PEG and HPS concentrations. The effects of NaCl addition, pH, and the load of cell supernatant on the partitioning of mAb in a PEG/HPS ATPS were investigated. It was found that with 6% cell supernatant and 15% NaCl addition at pH 6.0, the yield of mAb in the upper phase was 96.7% with a purity of 96.0%. The back-extraction of mAb with a PEG/phosphate ATPS were also studied, and the results showed that after the two-step extraction with ATPSs the purity of mAb could reach 97.6 ± 0.5% with a yield of 86.8 ± 1.0%, which was comparable to the purification with Protein A chromatography. These results indicate that the two-step extraction with PEG/HPS and PEG/phosphate ATPSs might be a promising alternative for the separation of mAb from cell culture supernatant.


Asunto(s)
Anticuerpos Monoclonales/aislamiento & purificación , Medios de Cultivo Condicionados/química , Polietilenglicoles/química , Almidón/análogos & derivados , Animales , Células CHO , Técnicas de Cultivo de Célula , Cromatografía Líquida de Alta Presión , Cricetulus , Almidón/química
3.
Mar Drugs ; 12(12): 6236-53, 2014 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-25532565

RESUMEN

Chitosan, the cationic polysaccharide derived from the natural polysaccharide chitin, has been studied as a biomaterial for more than two decades. As a polycationic polymer with favorable properties, it has been widely used to form polyelectrolyte complexes with polyanions for various applications in drug delivery fields. In recent years, a growing number of studies have been focused on the preparation of polyelectrolyte complexes based on chitosan and its water soluble derivatives. They have been considered well-suited as biomaterials for a number of vital drug carriers with targeted/controlled release profiles, e.g., films, capsules, microcapsules. In this work, an overview highlights not only the favorable properties of chitosan and its water soluble derivatives but also the good performance of the polyelectrolyte complexes produced based on chitosan. Their various types of applications as drug carriers are reviewed in detail.


Asunto(s)
Quitosano/química , Polímeros/química , Agua/química , Animales , Portadores de Fármacos/química , Humanos
4.
J Sep Sci ; 36(15): 2387-93, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23720373

RESUMEN

Bovine milk whey contains several bioactive proteins such as α-lactalbumin, ß-lactoglobulin, and immunoglobulin G (IgG). Chromatographic separation of these proteins has received much attention in the past few years. In this work, we provide a chromatographic method for the efficient isolation of IgG from bovine milk whey using a poly(2-hydroxyethyl methacrylate)-based anion-exchange cryogel. The monolithic cryogel was prepared by grafting 2-(dimethylamino) ethyl methacrylate onto the poly(2-hydroxyethyl methacrylate)-based cryogel matrix and then employed to separate IgG under various buffer pH and salt elution conditions. The results showed that the buffer pH and the salt concentration in the step elution have remarkable influences on the purity of IgG, while the IgG recovery depended mainly on the loading volume of whey for a given cryogel bed. High purity IgG (more than 95%) was obtained using the phosphate buffer with pH of 5.8 as the running buffer and the salt solution in as the elution liquid. With suitable loading volume of whey, the maximum IgG recovery of about 94% was observed. The present separation method is thus a potential choice for the isolation of high-purity IgG from bovine milk whey.


Asunto(s)
Criogeles/química , Inmunoglobulina G/aislamiento & purificación , Proteínas de la Leche/química , Polihidroxietil Metacrilato/química , Animales , Aniones/química , Bovinos , Cromatografía por Intercambio Iónico , Proteína de Suero de Leche
5.
J Sep Sci ; 36(24): 3813-20, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24151195

RESUMEN

A novel super-macroporous monolithic composite cryogel was prepared by embedding macroporous cellulose beads into poly(hydroxyethyl methacrylate) cryogel. The cellulose beads were fabricated by using a microchannel liquid-flow focusing and cryopolymerization method, while the composite cryogel was prepared by cryogenic radical polymerization of the hydroxyethyl methacrylate monomer with poly(ethylene glycol) diacrylate as cross-linker together with the cellulose beads. After graft polymerization with (vinylbenzyl)trimethylammonium chloride, the composite cryogel was applied to separate immunoglobulin-G and albumin from human serum. Immunoglobulin-G with a mean purity of 83.2% and albumin with a purity of 98% were obtained, indicating the composite cryogel as a promising chromatographic medium in bioseparation for the isolation of important bioactive proteins like immunoglobulins and albumins.


Asunto(s)
Celulosa/química , Criogeles/química , Inmunoglobulinas/aislamiento & purificación , Polihidroxietil Metacrilato/química , Albúmina Sérica/aislamiento & purificación , Humanos , Inmunoglobulinas/sangre , Microesferas , Tamaño de la Partícula , Porosidad , Propiedades de Superficie
6.
J Chromatogr A ; 1687: 463655, 2023 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-36442298

RESUMEN

Mechanistic models play a crucial role in the process development and optimization of ion-exchange chromatography (IEC). Recent researches in steric mass action (SMA) model have heightened the need for better estimation of nonlinear parameter, steric shielding factor σ. In this work, a straightforward approach combination of simplified linear approximation (SLA) and inverse method (IM) was proposed to initialize and further determine σ, respectively. An existed, unique, and positive σ can be derived from SLA. Compared with linear approximation (LA) developed in our previous study, σ of the multi-component system can be calculated easily without solving the complex system of linear equations, leading to a time complexity reduction from O(n3) to O(n). The proposed method was verified first in numerical experiments about the separation of three charge variants. The calculated σ was more reasonable than that of LA, and the error of elution profiles with the parameters estimated by SLA+IM was only one-sixth of that by LA in numerical experiments. Moreover, the error accumulation effect could also be reduced. The proposed method was further confirmed in real-world experiments about the separation of monomer-dimer mixtures of monoclonal antibody. The results gave a lower error and better physical understanding compared to LA. In conclusion, SLA+IM developed in the present work provides a novel and straightforward way to determine σ. This simplification would help to save the effort of calibration experiments and accelerate the process development for the multi-component IEC separation.


Asunto(s)
Anticuerpos Monoclonales , Polímeros , Cromatografía por Intercambio Iónico/métodos , Anticuerpos Monoclonales/química , Cromatografía Líquida de Alta Presión
7.
J Chromatogr A ; 1625: 461300, 2020 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-32709343

RESUMEN

Multi-column continuous chromatography has advantages of high resin capacity utilization and productivity, low buffer consumption and small footprint. Experimental optimization is often time-consuming and inefficient due to the complexity of continuous processes. In this study, a model-based approach was investigated to improve process development of twin-column continuous capture with Protein A affinity resin MabSelect PrismA. Breakthrough curves under various conditions, productivity and capacity utilization (CU) of the continuous processes under varying operating conditions were predicted. Effects of three key operating parameters (feed concentration (c0), interconnected feed residence time (RT) and breakthrough percentage control of the first column during interconnected feeding (s)) on the productivity and CU were evaluated. A recommended working window can be determined directly from contour maps to balance the trade-off between productivity and CU. The model-optimized operating conditions at varying feed concentrations were verified by experiments, which indicated that the model-based approach was feasible and reliable. The results showed that the suitable RT was 1~2 min and suitable s was 0.6~0.75 for the continuous IgG capture with MabSelect PrismA. The maximum productivity varied from 14 to 47 g/L/h with the feed IgG concentrations at the range of 1 to 10 mg/mL. The results indicated that model-based approach could assist process development efficiently and promote target-orientated process design for continuous processes.


Asunto(s)
Cromatografía de Afinidad/métodos , Modelos Teóricos , Resinas Sintéticas/química , Proteína Estafilocócica A/química , Humanos , Reproducibilidad de los Resultados , Factores de Tiempo
8.
J Chromatogr A ; 1533: 77-86, 2018 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-29241957

RESUMEN

This study investigated adsorption selectivity of immunoglobulin M (IgM), immunoglobulin A (IgA) and immunoglobulin (IgG) on four mixed-mode resins with the functional ligands of 4-mercatoethyl-pyridine (MEP), 2-mercapto-1-methylimidazole (MMI), 5-aminobenzimidazole (ABI) and tryptophan-5-aminobenzimidazole (W-ABI), respectively. IgM purification processes with mixed-mode resins were also proposed. All resins showed typical pH-dependent adsorption, and high adsorption capacity was found at pH 5.0-8.0 with low adsorption capacity under acidic conditions. Meanwhile, high selectivity of IgM/IgA and IgM/IgG was obtained with ABI-4FF and MMI-4FF resins at pH 4.0-5.0, which was used to develop a method for IgM, IgA and IgG separation by controlling loading and elution pH. Capture of monoclonal IgM from cell culture supernatant with ABI-4FF resins was studied and high purity (∼99%) and good recovery (80.8%) were obtained. Moreover, IgM direct separation from human serum with combined two-step chromatography (ABI-4FF and MMI-4FF) was investigated, and IgM purity of 65.2% and a purification factor of 28.3 were obtained after optimization. The antibody activity of IgM was maintained after purification. The results demonstrated that mixed-mode chromatography with specially-designed ligands is a promising way to improve adsorption selectivity and process efficiency of IgM purification from complex feedstock.


Asunto(s)
Técnicas de Química Analítica/métodos , Cromatografía , Inmunoglobulina M/aislamiento & purificación , Resinas Sintéticas/química , Adsorción , Células Cultivadas , Técnicas de Química Analítica/normas , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Inmunoglobulina A/metabolismo , Inmunoglobulina G/metabolismo , Inmunoglobulina M/metabolismo , Ligandos
9.
J Chromatogr A ; 1175(1): 55-62, 2007 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-17996880

RESUMEN

The specially designed adsorbent is one of the most important bases to achieve the expanded bed adsorption (EBA) process. The perfect adsorbents tend to be of small size, large pore and high density. In the present work a new kind of macroporous cellulose beads densified by high-density tungsten carbide were prepared through the method of water-in-oil suspension thermal regeneration. The cassava starch was used as porogenic agent during the preparation. Firstly the gelatinized starch solution was added into the cellulose viscose. After the formation of cellulose beads, the composite starch could be eliminated with boiling water wash and enzymatic hydrolyzation. The sphericity of cellulose beads was not influenced by starch addition and some amount of large pores with the diameter of about 1-3 microm could be formed in the beads. Varieties of physical properties, such as wet density, water content, porosity, specific surface area and mean pore diameter of the composite beads, as the function of starch addition were investigated. The analysis of elution peaks with model proteins (packed bed mode) indicated that the mass transfer kinetic inside the macroporous beads prepared was enhanced, which might certainly benefit the chromatographic operation under high flow rate. In addition, the prepared beads showed good expansion and stability in expanded bed, and are thus suitable for expanded bed applications.


Asunto(s)
Celulosa/síntesis química , Técnicas de Química Analítica/métodos , Microesferas , Compuestos de Tungsteno/síntesis química , Adsorción , Cromatografía , Porosidad , Agua
10.
J Chromatogr A ; 1512: 34-42, 2017 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-28720222

RESUMEN

Hydrophobic charge-induction chromatography (HCIC) with 4-mercaptoethyl-pyridine (MEP) as the functional ligand has been developed as a new technology for antibody purification. In the present work, molecular simulation methods were developed to investigate the interactions between the Fc fragment of IgG and a MEP ligand net. The MM/PBSA method was used to evaluate the binding energy for the MEP ligand net at different densities. It was found that ligand density had significant influence on the binding of Fc. Potential binding conformations were further analyzed by molecular dynamics simulation. It was found that the interaction between Fc and MEP ligand net is driven by self-adaptive conformation adjustment and multiple-site binding. Hydrophobic forces dominate the binding interaction, which appeared as the results of synergistic actions of binding sites located on CH2, CH3, and the consensus binding site (CBS) of the Fc fragment. At acidic pH, the electrostatic repulsion between the basic residues and the protonated pyridine ring group on MEP ligands is the main driving force for the detachment of the Fc fragment from the MEP net.


Asunto(s)
Anticuerpos/química , Cromatografía/instrumentación , Resinas Sintéticas/química , Anticuerpos/aislamiento & purificación , Sitios de Unión , Cromatografía/métodos , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Simulación de Dinámica Molecular , Unión Proteica , Piridinas/química , Electricidad Estática
11.
Artículo en Inglés | MEDLINE | ID: mdl-27978464

RESUMEN

Adsorption selectivity is critical important for mixed-mode chromatography with specially-designed ligands. Human immunoglobulin G (hIgG), Fc and Fab fragments were used in the present work to evaluate adsorption behavior and binding selectivity of four mixed-mode resins with the ligands of 4-mercatoethyl-pyridine (MEP), 2-mercapto-1-methylimidazole (MMI), 5-aminobenzimidazole (ABI) and tryptophan-5-aminobenzimidazole (W-ABI), respectively. The resins showed an obvious pH-dependent adsorption behavior. High adsorption capacities were found at neutral pH for hIgG, Fc and Fab, and almost no adsorption happened under acidic conditions. An adsorption selectivity index was proposed to evaluate separation efficiency. High specificity of hIgG/Fc was found at pH 8.9 for MEP resin, and for W-ABI resin at pH 8.0 and 8.9. In addition, isothermal titration calorimetry was used to evaluate ligand-protein interactions. Finally, the separation of hIgG and Fc (1:1) was optimized with mixed-mode resins, and the best separation performance was obtained with W-ABI-based resin. Loading at pH 8.0 resulted in the flow through of Fc with purity of 90.4% and recovery of 98.8%, while elution at pH 3.6 provided hIgG with purity of 99.7% and recovery of 86.5%.


Asunto(s)
Fragmentos Fab de Inmunoglobulinas/aislamiento & purificación , Fragmentos Fc de Inmunoglobulinas/aislamiento & purificación , Inmunoglobulina G/aislamiento & purificación , Adsorción , Bencimidazoles/química , Cromatografía Líquida de Alta Presión/métodos , Humanos , Imidazoles/química , Ligandos , Piridinas/química , Resinas Sintéticas/química , Triptófano/análogos & derivados
12.
J Chromatogr A ; 1107(1-2): 265-72, 2006 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-16406384

RESUMEN

For better understanding the influences of solid phase properties on the performance of the expanded bed, the expansion and hydrodynamic properties of cellulose-stainless steel powder composite matrix with a series of densities was investigated and analyzed in an expanded bed. Two kinds of matrix particle diameter fractions, the small one (60-125 microm) and the large (125-300 microm), were used in the present work. In general, the expansion factors decreased obviously with the increase of matrix density. A linear relation between the mean density of matrix and superficial velocity at expansion factor of 2.5 was found for same series of matrices. The Richardson-Zaki equation could correlate the bed expansion and operation fluid velocity for all matrices tested. The theoretical prediction of correlation parameters (the terminal settling velocity U(t) and expansion index n) was improved with the modification of equations in the literature. The residence time distributions were investigated to characterize the hydrodynamic property in expanded bed. Compared with three evaluation factors (the height equivalent of theoretical plate, Bo number and axial distribution coefficient D(ax)), the results indicated that D(ax) is the best parameter to analyze the bed stability of expanded bed under various operation conditions and matrix properties. In addition, it was found that fluid velocity is the most essential factor to influence the hydrodynamic properties in the bed. A linear relation between the D(ax) and superficial fluid velocity for all matrices tested was established.


Asunto(s)
Celulosa/química , Polvos , Acero Inoxidable/química , Adsorción
13.
Mater Sci Eng C Mater Biol Appl ; 59: 909-915, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26652447

RESUMEN

The micron-sized calcium alginate/sodium cellulose sulfate-water soluble chitosan (CA/NaCS-WSC) microcapsules were prepared by membrane emulsification method using sodium alginate (NaAlg), NaCS and WSC as raw materials. The CA/NaCS microspheres prepared dispersed well and held spherical shape with an emulsifier volume ratio of 7:3 (Span 80:Tween 80) and a concentration of cross-linking agent of 1.5% (w/v) calcium chloride and 5% (w/v) sodium chloride. The CA/NaCS-WSC microcapsules had a spherical shape with average diameter of 62.36±13.87µm. A fluorescent ring could be seen obviously on the surface of CA/NaCS-WSC microcapsules under confocal microscope, when WSC was labeled by fluorescein isothiocyanate. The discussion on the formation studies implied that Ca(2+) could diffuse into the droplets of NaAlg/NaCS forming CA/NaCS microspheres, while NaCS could react with WSC forming a polyelectrolyte complexes film. The microcapsules prepared with typical wall-capsule/core structure could be used to develop micron-sized drug delivery carriers.


Asunto(s)
Alginatos/química , Celulosa/análogos & derivados , Quitosano/química , Portadores de Fármacos/química , Cápsulas/química , Celulosa/química , Reactivos de Enlaces Cruzados , Emulsiones/química , Ácido Glucurónico/química , Ácidos Hexurónicos/química , Ensayo de Materiales
14.
Colloids Surf B Biointerfaces ; 45(3-4): 136-43, 2005 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-16199144

RESUMEN

A novel capsule system composed of sodium cellulose sulfate (NaCS), carboxymethyl cellulose (CMC) and poly[dimethyl(diallyl)ammonium chloride] (PDMDAAC) was prepared for improving the properties of NaCS/PDMDAAC capsules. The process parameters, such as CMC concentration (0, 2, 4, 6 and 8 g/L), NaCS concentration (20, 25, 30, 35 and 40 g/L), PDMDAAC concentration (20, 30, 40, 50, 60, 70 and 80 g/L), reaction time and temperature were investigated to understand their effects on the diameter, membrane thickness and mechanical strength of capsules. The optimum operation conditions for preparing NaCS-CMC/PDMDAAC capsules were determined as 6-8 g/L CMC, 35-40 g/L NaCS, 60 g/L PDMDAAC and polymerization for 30-40 min. Diffusion of substances with low molecular weight into capsules was investigated, and diffusion coefficients were calculated according to the developed model. The yeast of Candida krusei was chosen as representative cell to evaluate the effects of different cell loading on capsule mechanical strength. Meanwhile the encapsulated osmophilic C. krusei cells were cultured in 250 mL shaking flasks for 72 h to determine the cell leaking properties in short and long term.


Asunto(s)
Carboximetilcelulosa de Sodio/química , Celulosa/análogos & derivados , Polietilenos , Compuestos de Amonio Cuaternario , Sodio/química , Cápsulas/síntesis química , Cápsulas/química , Celulosa/química , Estructura Molecular , Tamaño de la Partícula , Polietilenos/síntesis química , Polietilenos/química , Compuestos de Amonio Cuaternario/síntesis química , Compuestos de Amonio Cuaternario/química , Propiedades de Superficie , Temperatura , Factores de Tiempo
15.
J Chromatogr A ; 1381: 173-83, 2015 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-25618356

RESUMEN

The preparation and characterization of mixed-mode adsorbents for a typical separation purpose are of great importance in bioseparation areas. In this work, we prepared a new monolithic cryogel with a combination of ion-exchange and hydrophobic functions by employing benzyl-quaternary amine groups. The fundamental cryogel properties, protein equilibrium adsorption isotherm and chromatographic adsorption in the cryogel were measured experimentally. The results showed that, by using bovine serum album as the model protein, the dual functional cryogel has protein binding capability even in salt solution and the buffer with pH close or below the protein isoelectric point due to both the electrostatic and hydrophobic interactions. A capillary-based adsorption model was developed, which provided satisfied insights of the microstructure, axial dispersion, mass transfer as well as protein adsorption characteristics within the cryogel bed. The chromatographic isolation of bioactive proteins from rabbit blood serum was carried out by the cryogel. Immunoglobulin G antibody with a purity of 98.2% and albumin with a purity of 96.8% were obtained, indicating that the cryogel could be an interesting and promising adsorbent in bioseparation areas.


Asunto(s)
Resinas Acrílicas/química , Criogeles/química , Inmunoglobulina G/química , Poliestirenos/química , Compuestos de Amonio Cuaternario/química , Albúmina Sérica/química , Adsorción , Animales , Bovinos , Cromatografía Liquida/métodos , Criogeles/síntesis química , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Peso Molecular , Conejos
16.
Artículo en Inglés | MEDLINE | ID: mdl-23603297

RESUMEN

The aqueous two-phase system (ATPS) with polyethylene glycol (PEG) and hydroxypropyl starch (HPS) was evaluated for the extraction of human immunoglobulin G (IgG) from human serum albumin (HSA). The partitions of IgG in PEG/sulphate, PEG/phosphate, PEG/Dextran and PEG/HPS ATPSs were compared, and the results indicated that PEG/HPS system was most suitable for IgG extraction. The effects of the concentrations of PEG, HPS and NaCl addition and pH on the partition of IgG and HSA in PEG/HPS ATPS were investigated. It was found that with 15% NaCl addition at pH 8.0 IgG could be largely recovered in the top PEG-rich phase and most of HSA kept in the bottom phase. In addition, the response surface methodology (RSM) was used to optimize the extraction of IgG from the protein mixture of IgG and HSA. The optimal conditions were obtained as 12% (w/w) PEG 4000, 18% (w/w) HPS and 10% (w/w) NaCl at pH 8.0. The extraction yield of IgG in the top phase was 99.2% and the purification factor could reach 5.28. The back extractions of IgG into a phosphate-rich bottom phase were also studied. The total purification factor was 5.73 with the yield of 84.0%. The results indicated that PEG/HPS ATPS might be a promising alternative for the primary recovery of IgG from the complicated feedstock.


Asunto(s)
Fraccionamiento Químico/métodos , Inmunoglobulina G/aislamiento & purificación , Polietilenglicoles/química , Almidón/análogos & derivados , Humanos , Concentración de Iones de Hidrógeno , Transición de Fase , Albúmina Sérica/aislamiento & purificación , Almidón/química
17.
Int J Pharm ; 455(1-2): 124-31, 2013 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-23891653

RESUMEN

Novel capsules loaded with lactoferrin (LF) were prepared using polyelectrolyte complexes that were formed by water soluble chitosan (WSC), sodium cellulose sulfate (NaCS) and sodium polyphosphate (PPS). Normal chitosan (soluble in acidic conditions) was chosen as a control to prepare similar capsules with NaCS and PPS. (1)H NMR and FTIR spectra analysis showed that WSC was in a form of chitosan hydrochloride which can be directly dissolved and protonated in acid-free water. SEM results showed that the capsules had a typical wall-capsule structure with a regular spherical shape and an average diameter of 1.97 mm. TGA studies revealed that the thermal stability of the capsules were enhanced and the moisture content of the drug-free/loaded capsules were 6.3% and 3.2%. SDS-PAGE results showed that the primary structures of the processed LF in the capsules were unchanged. Drug loading (LE%) and encapsulation efficiency (EE%) analysis showed that the capsules had a higher LE% (45.6%) and EE% (70.7%) than that of the control. In vitro release studies showed that the capsules had a regular and sustainable release profiles in simulated colonic fluid. All of these results indicated that the capsules prepared could be used as a candidate protein drug carrier for colon.


Asunto(s)
Celulosa/análogos & derivados , Quitosano/química , Sistemas de Liberación de Medicamentos , Lactoferrina/química , Polifosfatos/química , Secreciones Corporales/química , Cápsulas , Celulosa/química , Colon
18.
Carbohydr Polym ; 90(4): 1764-70, 2012 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-22944445

RESUMEN

The adsorption properties toward rutin of a cyclodextrin polymer adsorbent CroCD-TuC 3 have been studied. The adsorption capacity is reduced as temperature and pH of solution rises, but increases with the increase of solvent polarity. Compared with Sephadex™ G-15 dextran gel beads, CroCD-TuC 3 shows dramatically higher isosteric enthalpy due to a significant contribution of rutin/ß-cyclodextrin inclusion complex formation in CroCD-TuC 3 skeleton. A highlight in our study is that the pore diffusion model has been employed to describe the mass transfer inside the adsorbent pores. It reveals that the diffusion inside the pores is the rate-restricting step in the whole adsorption process. The effective pore diffusivity of rutin in CroCD-TuC 3 calculated is much lower than the diffusivity in diluted solution. The pore diffusion model is an available tool to investigate the profile of mass transfer inside the pores, and provides an effective method to describe adsorption kinetics.


Asunto(s)
Celulosa/química , Ciclodextrinas/química , Rutina/química , beta-Ciclodextrinas/química , Adsorción , Celulosa/metabolismo , Ciclodextrinas/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Rutina/metabolismo , Temperatura , Termodinámica , beta-Ciclodextrinas/metabolismo
19.
J Chromatogr A ; 1260: 143-53, 2012 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-22975355

RESUMEN

Hydrophobic charge-induction chromatography (HCIC) is a novel bioseparation technology, especially for antibody purification. In order to better understand the molecular mechanism of HCIC, the typical ligand of 4-mercaptoethyl-pyridine (MEP) was coupled onto the cellulose matrix, and the binding and departing of IgG were studied with the molecular dynamics simulation. Based on the previous work with free MEP ligand (J. Phys. Chem. B, 116 (4) (2012) 1393-1400), the pocket around TYR319 and LEU309 on the CH2 domain of IgG was selected as the potential binding site for the Fc fragment of IgG (Fc-A), and the complex of matrix-ligand-Fc-A was formed for the molecular simulation. Both single ligand and ligand net were investigated in the present work. It was found that the MEP ligand immobilized on the cellulose matrix could capture the Fc-A at neutral pH during the simulation, and the Fc-A would depart quickly when pH was changed to 4.0. The hydrophobic interactions and hydrogen bonds controlled the binding of Fc-A on the immobilized ligands at neutral pH and the electrostatic repulsion caused the departing of Fc-A at acid condition. For the ligand net, multipoint binding was found, while one ligand dominated the binding of Fc-A and other ligands might enhance the adsorption of protein. In addition, the adsorption isotherm and the isothermal titration calorimetry (ITC) were used to evaluate the molecular interactions. The experimental results indicated that the hydrophobic interaction is the major driving force for the adsorption of IgG on the MEP resin, which was in good agreement with those findings of molecular simulation. The molecular simulation and thermodynamic results verified strongly the molecular mechanism of HCIC--the hydrophobic interactions for binding and the charge-induction repulsion for elution. Better understanding on the molecular interactions would be beneficial to design new HCIC ligands for improving the efficiency of antibody separation.


Asunto(s)
Cromatografía Liquida/métodos , Inmunoglobulina G/química , Simulación de Dinámica Molecular , Piridinas/química , Adsorción , Celulosa/química , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Fragmentos Fc de Inmunoglobulinas/química , Fragmentos Fc de Inmunoglobulinas/metabolismo , Inmunoglobulina G/metabolismo , Ligandos , Unión Proteica , Piridinas/metabolismo , Termodinámica
20.
J Chromatogr A ; 1247: 81-8, 2012 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-22695698

RESUMEN

Polymeric cryogels are sponge-like materials with supermacroporous structure, allowing them to be of interest as new chromatographic supports, cell scaffolds and drug carriers in biological and biomedical areas. The matrices of cryogels are always prepared in the form of monoliths by cryo-polymerization under frozen conditions. However, there are limited investigations on the production of cryogels in the form of adsorbent beads suitable for bioseparation. In this work, we provide a new approach by combining the microchannel liquid-flow focusing with cryo-polymerization for the preparation of polyacrylamide-based supermacroporous cryogel beads with a narrow particle size distribution. The present method was achieved by introducing the aqueous phase solution containing monomer, cross-linker and redox initiators, and the water-immiscible organic oil phase containing surfactant simultaneously into a microchannel with a cross-shaped junction, where the aqueous drops with uniform sizes were generated by the liquid shearing and the segmentation due to the steady flow focusing of the immiscible phase streams. These liquid drops were in situ suspended into the freezing bulk oil phase for cryo-polymerization and the cryogel matrix beads were obtained by thawing after the achievement of polymerization. By grafting the polymer chains containing sulfo binding groups onto these matrix beads, the cation-exchange cryogel beads for protein separation were produced. The results showed that at the aqueous phase velocities from 0.5 to 2.0 cm/s and the total velocities of the water-immiscible phase from 2.0 to 6.0 cm/s, the obtained cryogel beads by the present method have narrow size distributions with most of the bead diameters in the range from 800 to 1500 µm with supermacropores in sizes of about 3-50 µm. These beads also have high porosities with the averaged maximum porosity of 96.9% and the mean effective porosity of 86.2%, which are close to those of the polyacrylamide-based cryogel monoliths. The packed bed using the cryogel beads with mean diameter of 1248 µm, as an example, has reasonable and acceptable liquid dispersion, but high water permeability (4.29 × 10⁻¹° m²) and high bed voidage (90.2%) owing to the supermacropores within the beads, enhanced the rapid binding and separation of protein from the feedstock even at high flow velocities. The purity of the obtained lysozyme from chicken egg white by one-step chromatography using the packed bed was in the range of about 78-92% at the flow velocities of 0.5-15 cm/min, indicating that the present cryogel beads could be an effective chromatographic adsorbent for primary bioseparation.


Asunto(s)
Resinas Acrílicas/química , Cromatografía por Intercambio Iónico/instrumentación , Cromatografía por Intercambio Iónico/métodos , Criogeles/química , Técnicas Analíticas Microfluídicas/métodos , Acrilamidas/química , Adsorción , Alcanosulfonatos/química , Criogeles/síntesis química , Electroforesis en Gel de Poliacrilamida , Microesferas , Muramidasa/química , Muramidasa/aislamiento & purificación , Tamaño de la Partícula , Permeabilidad
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