76
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Jaquet B, Lazzari S, Colonna L, Colombo G, Soos M, Morbidelli M. Effects of Coalescence on Shear-Induced Gelation of Colloids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1180-1188. [PMID: 28135093 DOI: 10.1021/acs.langmuir.6b03707] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Shearing lyophobic colloidal suspensions can lead to aggregation, followed by gelation, if the formed clusters grow to sizes large enough to percolate. If the temperature is set over the glass transition temperature of the suspended material, the particles embedded in the same aggregate start to coalesce with one another. Coalescence occurs to the finite viscosity of the particles' material, which leads to material diffusion from particle to particle. The driving force of this process is the reduction of the particle-dispersant interface and, as a consequence, the decrease the center-to-center separation of the particles. This leads to decreased cluster size, and hence a delayed gelation. Simultaneously, coalescence reinforces the particle-particle bonds formed upon aggregation, leading to clusters that are able to resist higher hydrodynamic forces before breaking up, hence leading to faster gelation. These two competing effects, combined with the natural complexity of colloidal aggregation makes it rather difficult to understand and predict which trend becomes dominant. In the present work, the shear-induced gelation of model polymeric colloidal systems with different glass transition temperatures has been studied. Starting with their interaction potential we investigate the impact of temperature on the gel time in concentrated suspensions (φ = 5%) under steady shear, followed by the effect of temperature on the stress-resistance of fully destabilized clusters under agitation. The results of the present work allow for a systematic view and deepened understanding of the factors governing shear-induced gelation in the presence of coalescence.
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77
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Lodi G, Storti G, Pellegrini LA, Morbidelli M. Ion Exclusion Chromatography: Model Development and Experimental Evaluation. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.6b04475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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78
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Ferrari R, Talamini L, Violatto MB, Giangregorio P, Sponchioni M, Morbidelli M, Salmona M, Bigini P, Moscatelli D. Biocompatible Polymer Nanoformulation To Improve the Release and Safety of a Drug Mimic Molecule Detectable via ICP-MS. Mol Pharm 2016; 14:124-134. [DOI: 10.1021/acs.molpharmaceut.6b00753] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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79
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Rosenboom JG, De Roo J, Storti G, Morbidelli M. Diffusion (DOSY) 1H NMR as an Alternative Method for Molecular Weight Determination of Poly(ethylene furanoate) (PEF) Polyesters. MACROMOL CHEM PHYS 2016. [DOI: 10.1002/macp.201600436] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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80
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Khalaf R, Coquebert de Neuville B, Morbidelli M. Protein adsorption in polyelectrolyte brush type cation-exchangers. J Chromatogr A 2016; 1471:126-137. [PMID: 27769533 DOI: 10.1016/j.chroma.2016.10.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/07/2016] [Accepted: 10/10/2016] [Indexed: 01/16/2023]
Abstract
Ion exchange chromatography materials functionalized with polyelectrolyte brushes (PEB) are becoming an integral part of many protein purification steps. Adsorption onto these materials is different than that onto traditional materials, due to the 3D partitioning of proteins into the polyelectrolyte brushes. Despite this mechanistic difference, many works have described the chromatographic behavior of proteins on polyelectrolyte brush type ion exchangers with much of the same methods as used for traditional materials. In this work, unconventional chromatographic behavior on polyelectrolyte brush type materials is observed for several proteins: the peaks shapes reveal first anti-Langmuirian and then Langmuirian types of interactions, with increasing injection volumes. An experimental and model based description of these materials is carried out in order to explain this behavior. The reason for this behavior is shown to be the 3D partitioning of proteins into the polyelectrolyte brushes: proteins that fully and readily utilize the 3D structure of the PEB phase during adsorption show this behavior, whereas those that do not show traditional ion exchange behavior.
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81
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Sokolov M, Ritscher J, MacKinnon N, Bielser JM, Brühlmann D, Rothenhäusler D, Thanei G, Soos M, Stettler M, Souquet J, Broly H, Morbidelli M, Butté A. Robust factor selection in early cell culture process development for the production of a biosimilar monoclonal antibody. Biotechnol Prog 2016; 33:181-191. [DOI: 10.1002/btpr.2374] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/27/2016] [Indexed: 01/23/2023]
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82
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Meng X, Wu H, Storti G, Morbidelli M. Effect of Dispersed Polymeric Nanoparticles on the Bulk Polymerization of Methyl Methacrylate. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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83
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Lazzari S, Nicoud L, Jaquet B, Lattuada M, Morbidelli M. Fractal-like structures in colloid science. Adv Colloid Interface Sci 2016; 235:1-13. [PMID: 27233526 DOI: 10.1016/j.cis.2016.05.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 04/13/2016] [Accepted: 05/02/2016] [Indexed: 01/20/2023]
Abstract
The present work aims at reviewing our current understanding of fractal structures in the frame of colloid aggregation as well as the possibility they offer to produce novel structured materials. In particular, the existing techniques to measure and compute the fractal dimension df are critically discussed based on the cases of organic/inorganic particles and proteins. Then the aggregation conditions affecting df are thoroughly analyzed, pointing out the most recent literature findings and the limitations of our current understanding. Finally, the importance of the fractal dimension in applications is discussed along with possible directions for the production of new structured materials.
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84
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Casalini T, Visscher F, Janssen E, Bertola F, Storti G, Morbidelli M. Modeling of Polyolefin Polymerization in Semibatch Slurry Reactors: Experiments and Simulations. MACROMOL REACT ENG 2016. [DOI: 10.1002/mren.201600036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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85
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Karst DJ, Steinebach F, Soos M, Morbidelli M. Process performance and product quality in an integrated continuous antibody production process. Biotechnol Bioeng 2016; 114:298-307. [DOI: 10.1002/bit.26069] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 07/13/2016] [Accepted: 08/02/2016] [Indexed: 12/30/2022]
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86
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Khalaf R, Heymann J, LeSaout X, Monard F, Costioli M, Morbidelli M. Model-based high-throughput design of ion exchange protein chromatography. J Chromatogr A 2016; 1459:67-77. [DOI: 10.1016/j.chroma.2016.06.076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/19/2016] [Accepted: 06/24/2016] [Indexed: 01/11/2023]
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87
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Sheng X, Xie D, Zhang X, Zhong L, Wu H, Morbidelli M. Uniform distribution of graphene oxide sheets into a poly-vinylidene fluoride nanoparticle matrix through shear-driven aggregation. SOFT MATTER 2016; 12:5876-5882. [PMID: 27334421 DOI: 10.1039/c6sm00551a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A general methodology has been developed for preparing nanocomposites with uniform, random distribution of fillers in polymer matrices, purely based on intense shear-driven aggregation, while avoiding filler aggregation. This procedure is demonstrated for a binary colloid composed of graphene oxide (GO) sheets and poly-vinylidene fluoride (PVDF) nanoparticles (NPs), both negatively charged and stable at rest. On the other hand, the PVDF NPs are shear-active (i.e. aggregation occurs under intensive shear), while the GO sheets are shear-inactive. It is found that when the two suspensions are mixed and the resulting binary colloid is forced to pass through a microchannel (MC) device (at a very high shear rate, G = 1.2 × 10(6) s(-1)), the shear-inactive GO sheets are captured and well distributed inside the PVDF NP clusters or gels. In addition, it is shown that in order to have 100% capture efficiency for the GO sheets, a minimum solid content of the binary colloid is required, which can be identified experimentally as the minimum leading to gelation after passing through the MC only one time.
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88
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Steinebach F, Müller-Späth T, Morbidelli M. Continuous counter-current chromatography for capture and polishing steps in biopharmaceutical production. Biotechnol J 2016; 11:1126-41. [PMID: 27376629 DOI: 10.1002/biot.201500354] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 12/21/2015] [Accepted: 05/30/2016] [Indexed: 12/11/2022]
Abstract
The economic advantages of continuous processing of biopharmaceuticals, which include smaller equipment and faster, efficient processes, have increased interest in this technology over the past decade. Continuous processes can also improve quality assurance and enable greater controllability, consistent with the quality initiatives of the FDA. Here, we discuss different continuous multi-column chromatography processes. Differences in the capture and polishing steps result in two different types of continuous processes that employ counter-current column movement. Continuous-capture processes are associated with increased productivity per cycle and decreased buffer consumption, whereas the typical purity-yield trade-off of classical batch chromatography can be surmounted by continuous processes for polishing applications. In the context of continuous manufacturing, different but complementary chromatographic columns or devices are typically combined to improve overall process performance and avoid unnecessary product storage. In the following, these various processes, their performances compared with batch processing and resulting product quality are discussed based on a review of the literature. Based on various examples of applications, primarily monoclonal antibody production processes, conclusions are drawn about the future of these continuous-manufacturing technologies.
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89
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Bertrand V, Karst D, Soos M, Morbidelli M. CHO cell proteome characterization for the continuous manufacturing of monoclonal antibodies. N Biotechnol 2016. [DOI: 10.1016/j.nbt.2016.06.869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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90
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Villiger TK, Scibona E, Stettler M, Broly H, Morbidelli M, Soos M. Controlling the time evolution of mAb N-linked glycosylation - Part II: Model-based predictions. Biotechnol Prog 2016; 32:1135-1148. [PMID: 27273889 DOI: 10.1002/btpr.2315] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 03/24/2016] [Indexed: 01/04/2023]
Abstract
N-linked glycosylation is known to be a crucial factor for the therapeutic efficacy and safety of monoclonal antibodies (mAbs) and many other glycoproteins. The nontemplate process of glycosylation is influenced by external factors which have to be tightly controlled during the manufacturing process. In order to describe and predict mAb N-linked glycosylation patterns in a CHO-S cell fed-batch process, an existing dynamic mathematical model has been refined and coupled to an unstructured metabolic model. High-throughput cell culture experiments carried out in miniaturized bioreactors in combination with intracellular measurements of nucleotide sugars were used to tune the parameter configuration of the coupled models as a function of extracellular pH, manganese and galactose addition. The proposed modeling framework is able to predict the time evolution of N-linked glycosylation patterns during a fed-batch process as a function of time as well as the manipulated variables. A constant and varying mAb N-linked glycosylation pattern throughout the culture were chosen to demonstrate the predictive capability of the modeling framework, which is able to quantify the interconnected influence of media components and cell culture conditions. Such a model-based evaluation of feeding regimes using high-throughput tools and mathematical models gives rise to a more rational way to control and design cell culture processes with defined glycosylation patterns. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1135-1148, 2016.
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91
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Steinhoff RF, Karst DJ, Steinebach F, Kopp MR, Schmidt GW, Stettler A, Krismer J, Soos M, Pabst M, Hierlemann A, Morbidelli M, Zenobi R. Microarray-based MALDI-TOF mass spectrometry enables monitoring of monoclonal antibody production in batch and perfusion cell cultures. Methods 2016; 104:33-40. [DOI: 10.1016/j.ymeth.2015.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 11/30/2015] [Accepted: 12/16/2015] [Indexed: 01/04/2023] Open
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92
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Sokolov M, Ritscher J, Souquet J, Broly H, Morbidelli M, Butté A. Shaping the quality of biopharmaceuticals – a multiscale perspective on the utilization of big data for efficient bioprocess development. N Biotechnol 2016. [DOI: 10.1016/j.nbt.2016.06.864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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93
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Lattuada M, Zaccone A, Wu H, Morbidelli M. Population-balance description of shear-induced clustering, gelation and suspension viscosity in sheared DLVO colloids. SOFT MATTER 2016; 12:5313-5324. [PMID: 27222249 DOI: 10.1039/c6sm01097k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Application of shear flow to charge-stabilized aqueous colloidal suspensions is ubiquitous in industrial applications and as a means to achieve controlled field-induced assembly of nanoparticles. Yet, applying shear flow to a charge-stabilized colloidal suspension, which is initially monodisperse and in quasi-equilibrium leads to non-trivial clustering phenomena (and sometimes to a gelation transition), dominated by the complex interplay between DLVO interactions and shear flow. The quantitative understanding of these strongly nonequilibrium phenomena is still far from being complete. By taking advantage of a recent shear-induced aggregation rate theory developed in our group, we present here a systematic numerical study, based on the governing master kinetic equation (population-balance) for the shear-induced clustering and breakup of colloids exposed to shear flow. In the presence of sufficiently stable particles, the clustering kinetics is characterized by an initial very slow growth, controlled by repulsion. During this regime, particles are slowly aggregating to form clusters, the reactivity of which increases along with their size growth. When their size reaches a critical threshold, a very rapid, explosive-like growth follows, where shear forces are able to overcome the energy barrier between particles. This stage terminates when a dynamic balance between shear-induced aggregation and cluster breakage is reached. It is also observed that these systems are characterized by a cluster mass distribution that for a long time presents a well-defined bimodality. The model predictions are quantitatively in excellent agreement with available experimental data, showing how the theoretical picture is able to quantitatively account for the underlying nonequilibrum physics.
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94
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Villiger TK, Roulet A, Périlleux A, Stettler M, Broly H, Morbidelli M, Soos M. Controlling the time evolution of mAb N-linked glycosylation, Part I: Microbioreactor experiments. Biotechnol Prog 2016; 32:1123-1134. [PMID: 27254475 DOI: 10.1002/btpr.2305] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 03/24/2016] [Indexed: 01/28/2023]
Abstract
N-linked glycosylation is of key importance for the efficacy of many biotherapeutic proteins such as monoclonal antibodies (mAbs). Media components and cell culture conditions have been shown to significantly affect N-linked glycosylation during the production of glycoproteins using mammalian cell fed-batch cultures. These parameters inevitably change in modern industrial processes with concentrated feed additions and cell densities beyond 2 × 107 cells/mL. In order to control the time-dependent changes of protein glycosylation, an automated microbioreactor system was used to investigate the effects of culture pH, ammonia, galactose, and manganese chloride supplementation on nucleotide sugars as well as mAb N-linked glycosylation in a time-dependent way. Two different strategies comprising of a single shift of culture conditions as well as multiple media supplementations along the culture duration were applied to obtain changing and constant glycosylation profiles. The different feeding approaches enabled constant glycosylation patterns throughout the entire culture duration at different levels. By modulating the time evolution of the mAb glycan pattern, not only the endpoint but also the ratios between different glycosylation structures could be modified. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1123-1134, 2016.
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95
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Karst DJ, Serra E, Villiger TK, Soos M, Morbidelli M. Characterization and comparison of ATF and TFF in stirred bioreactors for continuous mammalian cell culture processes. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2016.02.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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96
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Pfister D, Morbidelli M, Nicoud RM. A continuum theory for multicomponent chromatography modeling. J Chromatogr A 2016; 1446:50-8. [DOI: 10.1016/j.chroma.2016.03.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
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97
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Guélat B, Khalaf R, Lattuada M, Costioli M, Morbidelli M. Protein adsorption on ion exchange resins and monoclonal antibody charge variant modulation. J Chromatogr A 2016; 1447:82-91. [DOI: 10.1016/j.chroma.2016.04.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/01/2016] [Accepted: 04/07/2016] [Indexed: 01/18/2023]
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98
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Baur D, Angarita M, Müller-Späth T, Steinebach F, Morbidelli M. Comparison of batch and continuous multi-column protein A capture processes by optimal design. Biotechnol J 2016; 11:920-31. [PMID: 26992151 DOI: 10.1002/biot.201500481] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/23/2015] [Accepted: 03/09/2016] [Indexed: 11/06/2022]
Abstract
Multi-column capture processes show several advantages compared to batch capture. It is however not evident how many columns one should use exactly. To investigate this issue, twin-column CaptureSMB, 3- and 4-column periodic counter-current chromatography (PCC) and single column batch capture are numerically optimized and compared in terms of process performance for capturing a monoclonal antibody using protein A chromatography. Optimization is carried out with respect to productivity and capacity utilization (amount of product loaded per cycle compared to the maximum amount possible), while keeping yield and purity constant. For a wide range of process parameters, all three multi-column processes show similar maximum capacity utilization and performed significantly better than batch. When maximizing productivity, the CaptureSMB process shows optimal performance, except at high feed titers, where batch chromatography can reach higher productivity values than the multi-column processes due to the complete decoupling of the loading and elution steps, albeit at a large cost in terms of capacity utilization. In terms of trade-off, i.e. how much the capacity utilization decreases with increasing productivity, CaptureSMB is optimal for low and high feed titers, whereas the 3-column process is optimal in an intermediate region. Using these findings, the most suitable process can be chosen for different production scenarios.
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99
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Villiger TK, Steinhoff RF, Ivarsson M, Solacroup T, Stettler M, Broly H, Krismer J, Pabst M, Zenobi R, Morbidelli M, Soos M. High-throughput profiling of nucleotides and nucleotide sugars to evaluate their impact on antibody N-glycosylation. J Biotechnol 2016; 229:3-12. [PMID: 27131894 DOI: 10.1016/j.jbiotec.2016.04.039] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 04/16/2016] [Accepted: 04/20/2016] [Indexed: 01/25/2023]
Abstract
Recent advances in miniaturized cell culture systems have facilitated the screening of media additives on productivity and protein quality attributes of mammalian cell cultures. However, intracellular components are not routinely measured due to the limited throughput of available analytical techniques. In this work, time profiling of intracellular nucleotides and nucleotide sugars of CHO-S cell fed-batch processes in a micro-scale bioreactor system was carried out using a recently developed high-throughput method based on matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF-MS). Supplementation of various media additives significantly altered the intracellular nucleotides and nucleotide sugars that are inextricably linked to the process of glycosylation. The results revealed that UDP-Gal synthesis appeared to be particularly limiting whereas the impact of elevated UDP-GlcNAc and GDP-Fuc levels on the final glycosylation patterns was only marginally important. In contrast, manganese and asparagine supplementation altered the glycan profiles without affecting intracellular components. The combination of miniaturized cell cultures and high-throughput analytical techniques serves therefore as a useful tool for future quality driven media optimization studies.
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100
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Meng X, Wu H, Morbidelli M. Shear-driven aggregation of binary colloids for randomly distributing nanoparticles in a matrix. SOFT MATTER 2016; 12:3696-3702. [PMID: 26983559 DOI: 10.1039/c6sm00605a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We propose a methodology for preparing composite materials where A nanoparticles (NPs) are uniformly and randomly distributed inside a matrix of B NPs. It is based on intense shear-driven aggregation of binary colloids composed of A and B NPs, without using any additives. Its feasibility has been demonstrated using stable binary colloids composed of poly-methyl methacrylate (PMMA) particles and polystyrene (PS) particles. The PS particles alone undergo shear-driven aggregation (shear-active), while the PMMA particles alone do not exhibit any aggregation under the same conditions (shear-inactive). It is found that the shear-driven aggregation of the binary colloids does occur, and the formed clusters are composed of both the "shear-active" PS and "shear-inactive" PMMA particles. The SEM pictures demonstrate that the PMMA particles are uniformly and randomly distributed among the PS particles in the clusters, thus confirming the feasibility of the proposed methodology. The mechanism leading to the aggregation of the binary colloids has been discussed based on the experimental observations.
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