Human-design bioreactors

Alternatively, some subunit viral vaccines can be generated by rDNA techniques and expressed in a continuous ceU line or insect ceUs. Recent advances in bioreactor design and operation have improved the successful production of IPV in large-scale bioreactors. However, roUer bottles or flasks are stiU used for most current vaccine production. Development of insect ceU culture will allow for very large-scale Hquid suspension culture (143). Several vaccine candidates such as gpl60 for HIV and gD protein for herpes have been demonstrated in the insect ceU culture system. However, no vaccine has been approved for human use. 

Bader et al. [35] and De Bartolo et al. [36] developed the flat membrane bioreactor which consists of a multitude of stackable flat membrane modules as shown in Fig. 5. Each module has an oxygenating surface area of 1150 cm. Up to 50 modules can presently be run in parallel mode. Isolated hepatocytes are co-cultured with non-parenchymal cells. Liver cells are located of a distance of 20 pm of extracellular matrix from a supported polytetrafluorethylene (PTFE) film. Medium and cells in the modules are oxygenated in the incubator by molecular diffusion of air across the non-porous PTFE membrane. The design of the bioreactor is also the basis for its proven potential for cryostorage with fully differentiated adult primary human liver cells. 

It should be noted here that the bioartificial fiver device is not only a bioreactor but also a mass transfer device. The mass transfer of various nutrients from the blood into the liver cells, and also the transfer of many products of biochemical reactions from the cells into the bloodstream, should be efficient processes. In human fiver, the oxygen-rich blood is delivered via the hepatic artery, and bioartificial devices should be so designed that the oxygen can be easily delivered to the cells. 

Cimetta, E., E. FigaUo et al. 2009. Micro-bioreactor arrays for controlling cellular environments Design principles for human embryonic stem cell applications. Methods 47 81-89. 

Mesenchymal stem cells from the bone marrow of neonatal rats have been studied on electrospun PCL scaffolds. The cells have been cultured and differentiated in the presence of osteogenic supplements for up to four weeks, in a specifically designed rotational, oxygen-permeable bioreactor. In vivo, a strong resemblance is found between how these systems rapidly evolve and the natural bone tissue.Other studies have been focused on human mesenchymal stem cells, which can be effectively cultured on nanofiber scaffolds made of PCL or of... 

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