A NOVEL DIELECTROPHORESIS-BASED DEVICE FOR THE SELECTIVE RETENTION OFVIABLE CELLS IN CELL-CULTURE MEDIA

Cost-effective production of biopharmaceuticals on a large scale can b e carried out by perfusion cultures of mammalian cells. One problem wi th this mode of operation for submerged free-cell cultures is the requ irement for an efficient cell separation device located in the effluen t stream. The present work investigates the potential for the developm ent of a novel dielectrophoresis-based cell separator, capable of prov iding selective retention of viable cells in cell culture media, which are highly conductive. Predictions of the dielectrophoretic (DEP) res ponse in culture media were first obtained through a series of DEP-lev itation experiments. Subsequently, a prototype microelectrode ''fiIter '' was microfabricated and tested with C174 myeloma cell suspensions o f density 1 x 10(6) cells/mL. The optimum frequency range for selectiv e retention of viable cells was found in the range 5-15 MHz. A maximum separation efficiency of 98% was achieved at 10 MHz, with an applied peak-to-peak voltage of 30 V (maximum field strength of 10(5) V/m) and a flow rate of 30 mL/h which corresponds to a superficial velocity of 5.23 cm/h through the DEP-filter channels. (C) 1997 John Wiley & Sons , Inc.