Miniperm bioreactor

MiniPERM classic kit, molecular weight cutoff 12.5 kDa/vol 35 mL. Kit comprises 12 production modules, single packed, sterile four nutrient modules, reusable four stands for the MiniPERM bioreactor (cat. no. IV-76001055 Vivascience, Sartorius AG Weender Landstrasse 94-108, 37075 Goettingen, Germany). 

Universal turning device, which holds four miniPERM bioreactors (cat. no. IV-76001065 Vivascience). 

The hybridomas and secreted antibody are retained in the production module (Fig. 2). Depending on the cell line, cell densities can reach upwards of 1 x 107 cells/mL. The MiniPERM bioreactor is rotated on a universal turning device that allows four MiniPERM bioreactors to be run simultaneously for larger production runs of one hybridoma or production of different hybridomas. This motion speeds the distribution of nutrients to the cells and facilitates the removal of metabolic waste products and C02, processes that rely on passive diffusion in static bioreactors. Sample collection and harvesting is via Luer-Lock connections on the production module. The MiniPERM is a continuously fed culture system that allows cultures to be maintained for several weeks. 

Fig. 1. The MiniPERM bioreactor. Reproduced with permission from Joachim Liicke.

The MiniPERM bioreactor is our method of choice for the high-density culture of hybridoma cells (Fig. 1). The modular system, consisting of a 40-mL disposable culture chamber and a 550-mL reusable nutrient module separated by a dialysis membrane (12.5 kDa molecular weight cutoff), allows for the production of a low-volume, high-density cell population with a correspondingly high antibody yield. 

Assemble the MiniPERM bioreactor according to the manufacturer s instructions (see Note 9), disinfect the universal roller, and install in a C02 incubator. Media for the production module (production medium) and the nutrient module (nutrient medium) should be prepared before the inoculation (see Notes 1-4). The production medium is complete medium as described previously but supplemented with a further 5% FBS and 0.1% v/v CellPROTECT (see Note 10). The nutrient medium contains the same components as complete medium, with the exceptions of 5% FBS instead of 10% FBS and with the addition of 0.2% v/v AntiFOAMa (see Note 11). Both the nutrient media and the production media are prewarmed to 37°C to prevent expansion of the MiniPERM membrane when introduced into the incubator. 

There have been a number of membrane-based culture units developed (24), many based on dialysis tubing (1), and even available as large fermenters (Bioengineering AG Membrane Laboratory Fermenter with a Cuphron dialysis membrane of 10 000 dalton molecular weight cut-off forming an inner chamber). One of the more successful and currently available systems is described here—the miniPerm Bioreactor (Heraeus Instruments). 

The miniPERM Bioreactor (30, 31) consists of two components, the production module (40 ml) containing the ceUs and the nutrient module (600 ml of medirrm). The modules are separated by a semi-permeable dialysis membrane (MWCO 12.5 kDa) which retains the cells and mAb in the production module but allows metabolic waste products to diffuse out to the nutrient module. There is a permeable silicone rubber membrane for oxygenation and gas exchange in the production module. The whole unit rotates (up to 40 r.p.m.) within a CO2 incubator. It can be purchased as a complete disposable ready to use unit or the nutrient module (polycarbonate) can be autoclaved and reused at least ten times. 

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