WHEATON® CELLine is a range of membrane driven flasks for high density cell culture, designed to enhance small scale bio-production for antibody and protein generation. Conventional in vivo or in vitro cell culture methods can be laborious, may have low cell density and require significant purification. WHEATON® CELLine flasks address these three areas of limitation observed in static tissue culture flasks. The media compartment allows for bulk storage of cell culture growth medium. This reduces the media refreshing requirement significantly as the media compartment is fifty times the size of the cell compartment. With a 10 kDa cut off limit the metabolite regulating upper membrane regulates the flow of metabolites to and from the cell compartment and retains all proteins in the cell compartment. The cell compartment provides the ideal area to inoculate and achieve high density cultures by concentrating cells, their products, and limits the requirement for any exogenous growth factors. With static cultures, gas transfer rates can be the limiting factor in high density cultures but the WHEATON® CELLine flask places the cells directly against the gas permeable membrane to achieve optimal levels of oxygen and carbon dioxide.