Objectif - To study in depth the advantages of packed bed over conventional stirred microcarrier bioreactors for the cultivation of those mammalian cells that require a surface for their adherence and growth and for the production of biologically active macromolecules from such cells.- There are a large number of alternative systems for the productive and commercial use of anchorage dependent animal cells in culture. We have reviewed such systems, and have concluded that the packed bed of Fibra-cel offers the most potential for future developments. The studies we have undertaken with the Fibra-cel non-woven polyester material have demonstrated the feasibility of this system for the propagation of a number of cell types (BHKC13, Mouse Hybridoma, normal human fibroblasts and genetically engineered CHO cells). It also found to be suitable for the generation of product materials from such cells such as tissue-Plasminogen Activator, monoclonal antibodies and a genetically engineered cell producing Blood Factor VIII.- In producing antibody from a Hybridoma cell culture we have shown that the cells remain attached to the carrier when this is held in a rotating basket on the spinning shaft of a bioreactor. Furthermore the extended productivity of the antibody by the cells indicates that they retain their viability and physiological capabilities after an extensive habitation of the polyester matrix of the Fibra-cel material. A similar message may be obtained from the examination of normal human diploid fibroblasts secreting t-Plasminogen Activator. Such cells were maintained in their secreting mode for up to 40 days in a serum free medium while remaining attached to the Fibra-Cel carrier. These latter cultures were more productive than other microcarrier controls.- When cells produced on the carrier were compared with their controls grown on either glass or treated polystyrene, it was shown that it was not possible to obtain significant differences in either cell yield and viabilities or in those physiological parameters which were studied during the initial experimentation with the exception of the amount of lactic acid produced in treated polystyrene flask cultures that differed from both the Fibra-Cel and the standard Roller Bottle systems; the latter two systems, however, were not significantly different in any of the parameters' measures to date. Recent experiments are showing that it is possible to produce in a rotating basket packed bed system, which is geometrically equivalent system to the Fibra-cel containing roller bottle, results that are similar to those generated in the modified roller bottle. This result bridges the gap between what can be achieved under bench-scale conditions and the scaled-up systems that are commonly used in commercial operations. Follow-up- As the Fibra-cel system can be scaled-down to a 50 ml medium volume culture system held in a 120 ml roller bottle the development work on a new project may be conducted with considerable ease and efficiency in such a system. This will have the advantageous effect of scaling up to a unit process system based on over 100 litres of medium (a 2000 fold scale-up) without changing the substratum with which the cells interact. This facility should obviate the need to produce materials for the commercial market in systems based on the use of thousands of roller bottles (Erythropoietin) rather than in a scaled-up bioreactor containing a rotating basket of Fibra-cel discs;- There is also little doubt that the three-dimensional nature of the cell growth can be likened to that which occurs in the organs of animal bodies. It has therefore become clear to us that this system will not only provide a cost-effective way of producing products on the industrial scale from animal cells grown in culture but that it may also be used for the creation of artificial organs. Such a facility might be applied in both the further studies of the way cells interact with one another in the close confines of a three-dimensional structure but there may be further opportunities for exploiting such systems to process blood ex vivo as either an artificial liver or kidney. The practicability of replacing different organs in vivo remains to be determined as it is unlikely that the polyester/polypropylene material of the Fibra-cel would dissolve in vivo. Nevertheless, it is also unlikely that these materials will cause immunological problems. In addition to these potential uses of Fibra-cel based artificial organs, there is a present need to replace animals in test systems for new products and quality control procedures. The development of organ mimics which can be stored and transported easily would obviate the need for expensive, unreliable and unethical animal experimentation.We hired in a number of activities that will facilitate and expand the use of large-scale unit process packed bed reactors for the cultivation and exploitation of surface dependent and independent animal cells. This was achieved through the following experimental program :- Having examined a number of possible packing materials, such as treated polystyrene twisted ribbons, for the medium for the packed-bed, we decided to focus on the Fibra-cel non woven matrix of treated polystyrene fibres held in place by a coarse web of polypropylene filaments in the physical form of 6 mm diameter discs of about l mm in depth;- We designed, built and evaluated a number of bioreactor configurations in which the Fibra-cel carrier was used as the support substratum or capturing medium for the animal cells; we focused our attention on both a rotating sheet of the Fibra-cel held against the vertical end wall of a standard roller bottle and also a rotating basket of Fibra-cel discs which can be scaled-up to commercial levels;- We demonstrated the utility of the Fibra-cel system of cell cultivation for the production of tissue-Plasminogen Activator from an anchorage dependent normal human diploid fibroblast and a monoclonal antibody from a manufactured mouse cell hybridoma; in both of the latter cases, cultures were run in the continuous mode of operation and steady state productivities were obtained;- To bridge the gap between bench-scale systems based on roller bottles in which processes for the production of materials from animal cells are developed and the large-scale commercial operations, which could be over 100 litres in size and based on a rotating basket of Fibra-cel discs, we demonstrated, that by making a small modification to the standard roller bottle (by adding to it a sheet of Fibra-cel in which all the cells grew as the walls of the bottle were presiliconised) we could obtain the same kind of biological activity (as measured by cell growth and physicochemical parameters such as glucose utilisation, pH changes and lactic acid production) that would be obtained in a standard unsiliconised, unmodified roller bottle; and moreover it was possible to show, in a geometrically and volumetrically equivalent version of the Fibra-cel containing roller bottle, that similar kinds of productivities and physicochemical parameter changes could be obtained in a scaled-down version of the rotating basket system. Programme(s) IC-ISC C - Activity (Euratom, EEC) on cooperation in science and technology, 1984- Thème(s) Data not available Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur UNIVERSITY OF SURREY Contribution de l’UE Aucune donnée Adresse GU2 7XH GUILDFORD Royaume-Uni Voir sur la carte Liens Site web Opens in new window Coût total Aucune donnée
