Abstract: The invention relates to a method for the non-invasive selection of single living cells under gentle conditions from mixtures of cells or cell cultures with respect to a specific production performance. To this end, the concentration of substances produced by the individual cells which become enriched at the cell membrane, such as reporter gene products (GFP) or specifically secreted products, such as antibodies, is determined by fluorescence-microscopic detection methods.

Abstract: Initiation of growth and cultivation of cells can be performed by introducing the cells into culture compartments of a liquid-gas-phase exposure bioreactor containing a supply chamber in which there are disposed hollow-filament membranes having an inside diameter of no larger than 5 mm, wherein an inner volume of said hollow-filament membranes forms the culture compartments. Approximately one half of the supply chamber is filled with a nutrient medium and a remainder is filled with a gas mixture. Perfusion of medium and gas is turned on simultaneously or separately. The hollow-filament membranes and the cells contained therein are cyclically exposed to the gas or liquid phase.