Flocculation of biological cells: Experiment vs. theory

Han, Binbing; Akeprathumchai, Saengchai; Wickramasinghe, S. Ranil; Qian, Xianghong

doi:10.1002/aic.690490709

Cited by 39 publications

(45 citation statements)

References 50 publications

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“…Population balance models have been used to describe the growth of microbial cells (8)(9)(10)(11)(12) and other processes (13)(14)(15). They are based on the fact that the properties of the cell culture such as the age distribution of the cells present are not uniform but evolve with time.…”

Section: Introductionsupporting

confidence: 38%

Population Balance Approach to Modeling Hairy Root Growth

et al. 2004

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Though numerous models have been developed to describe the growth of microbial cell cultures, far fewer models are available to describe the growth of hairy root cultures. Here a population balance model is proposed to simulate the growth of hairy roots. The model accounts for the increase in biomass due to elongation of a branch by cell division as well as the formation of new branches. The model incorporates the fact that although the likelihood of the formation of a new lateral branch is a maximum at a specific age of the parent branch, lateral branches can form over a distribution of ages of the parent branch. Model parameters are estimated using the genetic algorithm based on experimental data for batch and continuous bioreactors. The model proposed here may provide a better understanding of the increase in biomass of hairy root cultures.

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Section: Introductionsupporting

confidence: 38%

Population Balance Approach to Modeling Hairy Root Growth

et al. 2004

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“…For the flocculated feed streams, although the modal particle size increases, the actual particle size distribution is broadened, as shown in Figure 3. In an earlier study, Han et al (2003) showed that flocculation of CHO cells often leads to a self-similar steady-state floc size distribution. Thus, some small particulate matter and cell debris remain.…”

Section: Discussionmentioning

confidence: 49%

Murine leukemia virus clearance by flocculation and microfiltration

Akeprathumchai¹,

Han²,

Wickramasinghe³

et al. 2004

Biotech & Bioengineering

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Clearance of murine leukemia virus from CHO cell suspensions by flocculation and microfiltration was investigated. Murine leukemia virus is a retrovirus that is recommended by the U.S. Food and Drug Administration for validating clearance of retrovirus-like particles. Due to biosafety considerations, an amphotropic murine leukemia virus vector (A-MLV) that is incapable of self-replication was used. Further, A-MLV is incapable of infecting CHO cells, thus ensuring that infection of the CHO cells in the feed did not result in a reduced virus titer in the permeate. The virus vector contains the gene for the enhanced green fluorescent protein (EGFP) to facilitate assaying for infectious virus particles. The virus particles are 80-130 nm in size. The feed streams were flocculated using a cationic polyelectrolyte. Microfiltration was conducted using 0.1 and 0.65 microm pore size hollow fiber membranes. The level of virus clearance in the permeate was determined. For the 0.1 microm pore size membranes a 1,000-fold reduction in the virus titer in the permeate was observed for feed streams consisting of A-MLV, A-MLV plus flocculant, A-MLV plus CHO cells, and A-MLV plus flocculant and CHO cells. While the flocculant had little effect on the level of virus clearance in the permeate for 0.1 microm pore size membranes, it did lead to higher permeate fluxes for the CHO cell feed streams. Virus clearance experiments conducted with 0.65 microm pore size membranes indicate little clearance of A-MLV from the permeate in the absence of flocculant. However, in the presence of flocculant the level of virus clearance in the permeate was similar to that observed for 0.1 microm pore size membranes. The results obtained here indicate that significant clearance of A-MLV is possible during tangential flow microfiltration. Addition of a flocculant is essential if the membrane pore size is greater than the diameter of the virus particles. Flocculation of the feed stream leads to an increase in the permeate flux.

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“…Beyond typical industrial processes, agglomeration plays a role in diverse bio-related applications such as blood flow dynamics and bio-molecular cross-linking of particles (Han et al 2003, Hiddessen et al 2004.…”

Section: Introductionmentioning

confidence: 45%

On the nature, formation and diversity of particulate coherent structures in microgravity conditions and their relevance to materials science and problems of astrophysical interest

Lappa

2016

Geophysical & Astrophysical Fluid Dynamics

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Different phenomena related to the spontaneous accumulation of solid particles dispersed in a fluid medium in microgravity conditions are discussed, with an emphasis on recent discoveries and potential links with the general field of astrophysical fluid-dynamics on the one hand, and with terrestrial applications in the field of materials science on the other hand. With special attention to the typical physical forces at play in such an environment, namely, surface-tension gradients, oscillatory residual gravity components, inertial disturbances and forces of an electrostatic nature, specific experimental and numerical examples are presented to provide inputs for an increased understanding of the underlying cause-and-effect relationships. Studying these systems can be seen as a matter of understanding how macroscopic scenarios arise from the cooperative behaviour of sub-parts or competing mechanisms (nonlinearities and interdependencies on various spatial and temporal scales). Through a critical assessment of the properties displayed by the resulting structures (which appear in the form of one-dimensional circuits formed by aligned particles, planar accumulation surfaces, three-dimensional compact structures resembling “quadrics”, micro-crystallites or fractal aggregates), we discuss a possible classification of the related particle attractors in the space of parameters according to the prevailing effect

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Flocculation of biological cells: Experiment vs. theory

Abstract: Flocculation of biological cells is important in the biotechnology industry, as it could

Cited by 39 publications

References 50 publications

Population Balance Approach to Modeling Hairy Root Growth

Population Balance Approach to Modeling Hairy Root Growth

Murine leukemia virus clearance by flocculation and microfiltration

On the nature, formation and diversity of particulate coherent structures in microgravity conditions and their relevance to materials science and problems of astrophysical interest

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