Oxygen permeability disposal

Recently developed blood oxygenators are disposable, used only once, and can be presterilized and coated with anticoagulant (e.g., heparin) when they are constructed. Normally, membranes with high gas permeabilities, such as silicone rubber membranes, are used. In the case of microporous membranes, which are also used widely, the membrane materials themselves are not gas permeable, but gas-liquid interfaces are formed in the pores of the membrane. The blood does not leak from the pores for at least several hours, due to its surface tension. Composite membranes consisting of microporous polypropylene and silicone rubber have also been developed. 

The migration of gas becomes an important consideration in certain geoenvironmental engineering applications when the gas content in a porous medium is sufficiently high such that the gas phase is continuous. Examples of such apphcations include the removal of VOCs and SVOCs from the imsaturated or vadose zone above the water table in the subsurface via the gas phase and the minimization of oxygen influx or radon efflux from engineered covers for tailings disposal applications. In the former case, removal efficiency is improved as gas permeability increases, whereas in the latter case, the objective is to minimize the gas permeability and therefore minimize the gas flow. 

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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