Optimizing Culture Conditions for the Production of Animal Cells in Microcarrier Culture

Abstract

Cytodex 1 microcarriers have been used for the successful culture of more than 80 different types of animal cells--including primary cells, normal diploid cell strains and established or transformed cell lines. culture volumes have ranged from a few milliliters for diagnostic studies to over several hundred liters for vaccine production. Experience with this wide variety of cell types and culture volumes has enabled the identification of several parameters critical for obtaining maximum cell yields from microcarrier cultures. The most vital stage for the successful microcarrier culture of many cell types was the initial stage of the culture cycle. To achieve high cell yields, it was necessary to use culture procedures which maximized plating efficiency and final cell yield could be further increased by ensuring that the inoculation cell density exceeded a critical viable cell/microcarrier ratio. Modifications of the standard microcarrier culture procedures included reducing initial culture volume, reducing the initial stirring speed and/or supplementing the medium during the early stages of the culture cycle. Control of pH, nutrient supply, and gas tension were all critical throughout the culture cycle. Results with low-serum and serum-free media indicate that the requirement for fetal calf serum in the microcarrier culture of Vero and MRC-5 cells can be reduced or even eliminated. Large scale microcarrier culture equipment should take into account the modified culture procedures which are often required to achieve the full potential of this culture method. The design of a new flexible culture system suitable for pilot and production scale cultures is presented. This system accomodates a wide variety of culture and production procedures and through a recirculation system permits: (a) "in-line" monitoring and control of culture parameters; (b) provides an efficient gas exchange capacity which obviates the need for fermenter headspace and sparging; and (c) allows for maximal utilization of medium components and rapid harvesting of medium or cell products.

Reactor Engineering in Large Scale Animal Cell Culture

“…It has been recognised for some time (Clark and Hirtenstein 1981;Sinskey et al 1981) that the use of relatively small particles (of the order of 150-200 lm), either solid or macroporous, enables a large surface area for cell growth to be available in the bioreactor and hence increases the cell density that can be achieved. However, all of the concerns discussed above with respect to oxygen transfer, homogenisation and 'shear' sensitivity also have to be considered once again.…”

Growth of an adherent continuous cell line entrapped in a peg/alginate matrix

“…Thus, the procedure of bead re-solubilization, dilution and reformation apparently had no detrimental effect on cell growth. The cell densities achieved in the PEG/alginate beads are compared to those obtained with other microcarriers in Figure 2 (Baijot et al 1987;Beaudry et al, 1979;Butler, 1985Butler, , 1987Clark, 1981;Crespi, 1981;Forestall et al, 1992;Giard et al, 1977Giard et al, , 1979Himes & Hu, 1987;Hu et al, 1987;Levine et al, 1978Matsushita et al, 1990Matsushita et al, , 1991Reuveny et al, 1983;Runstadler & Cernek, 1988;Scattergood et al, 1983;Tat et al, 1988;Thill~'.. et al, 1982;van Hemert et al, 1969;Varani et al, 1983;Whiteside & Spier, 1981;Whiteside et al, 1982;Yanagi et al, 1992). When corrected for microcarrier loading in the reactor, the capacity of the PEG/alginate beads, as might be expected, is comparable to that demonstrated for other macroporous carriers, such as the Verax collagen beads (Runstadler, 1988).…”

Preparation of microcarriers based on zein and their application in cell culture

“…Since its first use in adherent animal cell culture by Van Wezel et al [10], the microcarrier technique has become an effective method for large-scale amplification of animal cells and has been successfully used for vaccine production and gene engineering [11]. Microcarriers offer many advantages over traditional culture technology: they have a large surface area, the process parameters can be effectively traced and controlled, the cost is low, and a higher cell density can be produced [12].…”