A MODIFIED CONTINUOUS-FLOW MICROCALORIMETER FOR MEASURING HEAT DISSIPATION BY MAMMALIAN-CELLS IN BATCH CULTURE

Microcalorimeters to monitor the heat dissipation of bench-scale anima l cell cultures on line and in real time require a continuous circuit between the vessel measuring heat flow rate and the bioreactor. The mo difications to the transmission lines and calorimetric heat exchanger were to: (i) reverse the usual upward direction of the cell suspension in the flow vessel to downwards; (ii) install an in situ washing/clea ning facility; (iii) use low diffusivity PEEK material; and (iv) maint ain thermal equilibration by water-jacketing the transmission tubing. Chemical calibration showed that there was more than a 20% difference between the physical volume and the effective thermal volume. An appro priate thermodynamic system was defined in order to permit enthalpy ba lance studies.