226
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Gauer C, Wu H, Morbidelli M. Control of Coalescence in Clusters of Elastomer Colloids through Manipulation of Polymer Composition. Macromolecules 2009. [DOI: 10.1021/ma901707s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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227
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Gauer C, Wu H, Morbidelli M. Effect of surface properties of elastomer colloids on their coalescence and aggregation kinetics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:12073-12083. [PMID: 19610664 DOI: 10.1021/la901702s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We study the aggregation kinetics of two elastomer colloids with similar bulk polymer properties but with different surface charge groups in order to understand the role of the surface properties in particle coalescence during aggregation. It is confirmed that clusters of the elastomer particles stabilized purely by ionic surfactants coalesce in both reaction-limited and diffusion-limited aggregation (RLCA and DLCA) regimes and that the coalescence is independent of the coagulant type. On the other hand, clusters formed by elastomer particles stabilized by charged polymer end groups, which are fixed on the particle surface, are fractal objects with a fractal dimension of 1.7 in the DLCA and 2.1 in the RLCA regime. This indicates insignificant cluster coalescence during aggregation, most likely due to a hindrance effect of the fixed charges.
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228
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Tanzeglock T, Soos M, Stephanopoulos G, Morbidelli M. Induction of mammalian cell death by simple shear and extensional flows. Biotechnol Bioeng 2009; 104:360-70. [PMID: 19575444 DOI: 10.1002/bit.22405] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work we investigated whether the type of shear flow, to which cells are exposed, influences the initiation of cell death. It is shown that mammalian cells, indeed, distinguish between discrete types of flow and respond differently. Two flow devices were employed to impose accurate hydrodynamic flow fields: uniform steady simple shear flow and oscillating extensional flow. To distinguish between necrotic and apoptotic cell death, fluorescence activated cell sorting and the release of DNA in the culture supernatant was used. Results show that Chinese Hamster Ovaries and Human Embryonic Kidney cells will enter the apoptotic pathway when subjected to low levels of hydrodynamic stress (around 2.0 Pa) in oscillating, extensional flow. In contrast, necrotic death prevails when the cells are exposed to hydrodynamic stresses around 1.0 Pa in simple shear flow or around 500 Pa in extensional flow. These threshold values at which cells enter the respective death pathway should be avoided when culturing cells for recombinant protein production to enhance culture longevity and productivity.
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229
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Müller-Späth T, Aumann L, Ströhlein G, Morbidelli M. Improvement of specific monoclonal antibody (mAb) activity by reduction of the mAb heterogeneity using continuous chromatography (MCSGP). N Biotechnol 2009. [DOI: 10.1016/j.nbt.2009.06.740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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230
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Gauer C, Jia Z, Wu H, Morbidelli M. Aggregation kinetics of coalescing polymer colloids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9703-9713. [PMID: 19492824 DOI: 10.1021/la900963f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The aggregation behavior of a soft, rubbery colloidal system with a relatively low glass transition temperature, T(g) approximately -20 degrees C, has been investigated. It is found that the average gyration and hydrodynamic radii, R(g) and R(h), measured by light scattering techniques, evolve in time in parallel, without exhibiting the crossover typical of rigid particle aggregation. Cryogenic scanning electron microscopy (cryo-SEM) images reveal sphere-like clusters, indicating that complete coalescence between particles occurs during aggregation. Since coalescence leads to a reduction in the total colloidal surface area, the surfactant adsorption equilibrium, and thus the colloidal stability, change in the course of aggregation. It is found that to simulate the observed kinetic behavior based on the population balance equations, it is necessary to assume that all the clusters are spherical and to account for variations in the colloidal stability of each aggregating particle pair with time. This indicates that, for the given system, the coalescence is very fast, i.e., its time scale is much smaller than that of the aggregation.
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231
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Morbidelli M. Purification of monoclonal antibodies by continuous chromatography (MCSGP). N Biotechnol 2009. [DOI: 10.1016/j.nbt.2009.06.704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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232
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Tanzeglock T, Soos M, Morbidelli M. Prediction of cell damage in stirred bioreactors—from small-scale model systems to a novel bioreactor design. N Biotechnol 2009. [DOI: 10.1016/j.nbt.2009.06.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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233
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Ehrl L, Soos M, Morbidelli M, Bäbler MU. Dependence of initial cluster aggregation kinetics on shear rate for particles of different sizes under turbulence. AIChE J 2009. [DOI: 10.1002/aic.11923] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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234
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Thomas H, Storti G, Butté A, Joehnck M, Schulte M, Morbidelli M. Tentacles in biochromatography. CHEM-ING-TECH 2009. [DOI: 10.1002/cite.200950667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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235
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236
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Zaccone A, Soos M, Lattuada M, Wu H, Bäbler MU, Morbidelli M. Breakup of dense colloidal aggregates under hydrodynamic stresses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:061401. [PMID: 19658503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Indexed: 05/28/2023]
Abstract
Flow-induced aggregation of colloidal particles leads to aggregates with fairly high fractal dimension (df approximately 2.4-3.0) which are directly responsible for the observed rheological properties of sheared dispersions. We address the problem of the decrease in aggregate size with increasing hydrodynamic stress, as a consequence of breakup, by means of a fracture-mechanics model complemented by experiments in a multipass extensional (laminar) flow device. Evidence is shown that as long as the inner density decay with linear size within the aggregate (due to fractality) is not negligible (as for df approximately 2.4-2.8), this imposes a substantial limitation to the hydrodynamic fragmentation process as compared with nonfractal aggregates (where the critical stress is practically size independent). This is due to the fact that breaking up a fractal object leads to denser fractals which better withstand stress. In turbulent flows, accounting for intermittency introduces just a small deviation with respect to the laminar case, while the model predictions are equally in good agreement with experiments from the literature. Our findings are summarized in a diagram for the breakup exponent (governing the size versus stress scaling) as a function of fractal dimension.
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237
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Wu H, Zaccone A, Tsoutsoura A, Lattuada M, Morbidelli M. High shear-induced gelation of charge-stabilized colloids in a microchannel without adding electrolytes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:4715-4723. [PMID: 19260654 DOI: 10.1021/la803789s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We study shear-induced gelation in a microchannel without adding any salt, for a polymer colloid that is fully stable under stagnant conditions. The initial stability is achieved by negative charges from the polymer chain end groups. Then, sulfonate surfactants are added to the system. The surfactant adsorption is characterized by coexistence of domains of gaseous-like noninteracting molecules (G) and condensed patches of interacting molecules (K). It is found that, for a fixed, substantially high shear rate of 1x10(6) 1/s (Peclet number=4.5x10(4)), in the absence of surfactants, the shear-induced gelation of the system does occur, and when the surfactants are added, as the surfactant surface coverage on the particles increases to a certain value, the shear-induced gelation or even small extent of aggregation becomes impossible. We have estimated the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy barrier from the measured zeta-potentials and found that in all the cases the corresponding shear-induced collision energy is orders of magnitude larger than the required energy to overcome the barrier. Thus, one would expect occurrence of gelation for all the systems. This clearly indicates presence of additional non-DLVO interactions, which under very low ionic strength are related to the adsorbed surfactant patches that generate strongly repulsive, short-range hydration force. Moreover, when no gelation but only aggregation occurs after passing through the microchannel, the cluster size distribution exhibits distinct bimodality. The structure of the obtained gels also depends on the surfactant surface coverage.
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238
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Ehrl L, Jia Z, Wu H, Lattuada M, Soos M, Morbidelli M. Role of counterion association in colloidal stability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:2696-2702. [PMID: 19437751 DOI: 10.1021/la803445y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A generalized model for colloidal stability has been validated against experimentally measured values of Fuchs stability ratio and critical coagulation concentration (ccc) for electrolytes with mono- or divalent cation, i.e., potassium chloride and magnesium chloride, respectively. Besides the classical DLVO theory, the generalized model accounts for the interplay between colloidal interactions and the association of cations with the particles surface charge groups. The model parameters are either obtained or estimated purely on the basis of independent information available in the literature. For the monovalent salt, the predictions agree well with literature experimental data, forecasting both the ccc values and stability ratios quantitatively. For the divalent salt the predictions for large values of the stability ratio tend to deviate from the experimental data produced in this work, but it is noted that the onset of stability, i.e., the ccc, and small stability ratios are correctly predicted. Moreover, a comparison of the above results with those neglecting the effect of counterion association with the particles surface charge groups indicates that the latter substantially overestimates stability ratios in the presence of high salt concentration in the case of the monovalent salt, and leads to unrealistic large values of the ccc for the divalent salt. Including the association of cations with the particles surface charge groups can explain the relatively low values of experimental ccc for divalent salts compared to the theoretical predictions by the classical DLVO theory neglecting ion association, which is apoint of interest in industrial coagulation processes.
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239
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Lattuada M, Furlan M, Butté A, Morbidelli M. Polymer and Colloid Highlights: Novel Anisotropic Porous Materials through Self-Assembly of Super-Paramagnetic Particles. Chimia (Aarau) 2009. [DOI: 10.2533/chimia.2009.78] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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240
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Müller-Späth T, Aumann L, Morbidelli M. Role of Cleaning-in-Place in the Purification of mAb Supernatants Using Continuous Cation Exchange Chromatography. SEP SCI TECHNOL 2009. [DOI: 10.1080/01496390802581243] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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241
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Morbidelli M, Subramaniam B. Arvind Varma: Educator, Researcher and Leader. Ind Eng Chem Res 2008. [DOI: 10.1021/ie801563q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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242
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Zaccone A, Wu H, Portaluri A, Lattuada M, Morbidelli M. Mechanically stirred single-stage column for continuous gelation of colloidal systems. AIChE J 2008. [DOI: 10.1002/aic.11620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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243
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Forrer N, Butté A, Morbidelli M. Chromatographic behavior of a polyclonal antibody mixture on a strong cation exchanger column. Part I: Adsorption characterization. J Chromatogr A 2008; 1214:59-70. [DOI: 10.1016/j.chroma.2008.10.048] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Revised: 10/07/2008] [Accepted: 10/13/2008] [Indexed: 10/21/2022]
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244
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Costa LI, Kasëmi E, Storti G, Morbidelli M, Walde P, Schlüter AD. Dendronized Polymers via Macromonomer Route in Supercritical Carbon Dioxide. Macromol Rapid Commun 2008. [DOI: 10.1002/marc.200800250] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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245
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Forrer N, Kartachova O, Butté A, Morbidelli M. Investigation of the Porosity Variation during Chromatographic Experiments. Ind Eng Chem Res 2008. [DOI: 10.1021/ie800131t] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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246
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Müller-Späth T, Aumann L, Melter L, Ströhlein G, Morbidelli M. Chromatographic separation of three monoclonal antibody variants using multicolumn countercurrent solvent gradient purification (MCSGP). Biotechnol Bioeng 2008; 100:1166-77. [DOI: 10.1002/bit.21843] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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247
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Melter L, Butté A, Morbidelli M. Preparative weak cation-exchange chromatography of monoclonal antibody variants. J Chromatogr A 2008; 1200:156-65. [DOI: 10.1016/j.chroma.2008.05.061] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 05/08/2008] [Accepted: 05/22/2008] [Indexed: 10/22/2022]
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248
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Mittal V, Matsko NB, Butté A, Morbidelli M. PNIPAAM Grafted Polymeric Monoliths Synthesized by the Reactive Gelation Process and their Swelling/Deswelling Characteristics. MACROMOL REACT ENG 2008. [DOI: 10.1002/mren.200700052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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249
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Zaccone A, Wu H, Lattuada M, Morbidelli M. Charged Molecular Films on Brownian Particles: Structure, Interactions, and Relation to Stability. J Phys Chem B 2008; 112:6793-802. [DOI: 10.1021/jp801423h] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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250
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Zaccone A, Wu H, Lattuada M, Morbidelli M. Correlation between Colloidal Stability and Surfactant Adsorption/Association Phenomena Studied by Light Scattering. J Phys Chem B 2008. [DOI: 10.1021/jp803415k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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