Abstract: Provided herein are methods of quantifying extracellular vesicle concentration, such as exosomes, by measuring cholesterol content in a sample. Also provided are methods of processing extracellular vesicles to remove non-exosomal species which contain cholesterol.

Abstract: The invention is a method of preventing the generation of pink color during antibody manufacturing by either preventing the reduction of antibodies during manufacturing and harvest or inhibiting the conversion of cyanocobalamin (CN-Cbl) to hydroxocobalamin (HO-Cbl) during manufacturing and harvest. Replacement of white light in the cell culture media preparation and storage areas with red light inhibits the conversion of CN-Cbl to HO-Cbl. Addition of peroxides to the clarified bulk at harvest inhibits reduction of the antibody disulfide bonds.

Abstract: The present invention relates to the use of online biomass capacitance monitoring in perfusion cultures as a way to minimize volumes of cell culture media in large-scale manufacturing. In certain embodiments, a biomass capacitance probe is used to measure the viable cell density, and the viable cell density is used in conjunction with a pre-determined constant cell-specific perfusion rate to identify a target perfusion rate.