Author Archives: John Carvell

Photo 1: Original disposable Aber Instruments biomass probe attached to light-weight preamplifier

Monitoring Live Biomass in Disposable Bioreactors

Often simply referred to as capacitance, radio-frequency (RF) impedance has been used for over two decades to measure online biomass. It is generally regarded as the most robust and reliable method to monitor live-cell concentrations in mammalian cell culture (1). Many biopharmaceutical companies have now made the transition from conventional glass or stainless steel multiuse (MU) vessels to single-use (SU) bioreactors. Disposables are rapidly becoming the preferred platform for new processes requiring current good manufacturing practice (CGMP) compliance. At the…

A Biomass Monitor for Disposable Bioreactors

    Of the available on-line biomass assay types, radio-frequency impedance spectroscopy (RFI, often referred to as capacitance) is generally regarded as the most robust and reliable method for monitoring viable biomass during fermentation and cell culture. The first article to show that capacitance could be used to estimate microbial biomass dates back over 20 years (1). Today the technology is routinely used for monitoring and controlling mammalian cell culture processes and high-density yeast and bacterial fermentations in research, process…