Ultrasonic Separation of Suspended Particles - Part III: Application in Biotechnology

This paper describes a novel acoustic filter for the retention of mammalian cells in cell culture fermentations. The filter is based on a multilayered piezoelectric resonator. It is operated in flow-through mode and utilizes the acoustic forces on the cells in a standing ultrasonic field. The background of animal cell culture fermentation is briefly reviewed. The functional principle, the resonator design, and the implementation of the acoustic filter are discussed. System performance is analyzed by comparison to conventional stirred tank fermentation. Experimental results obtained with two different hybridoma cell lines (human hybridoma with average cell concentration and mouse hybridoma with high concentration) are presented. A significant increase of cell concentrations and product output (daily harvest) could be achieved with this new acoustic filter technique.