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The productivity of cell culture-derived vaccines grown in anchorage-dependent animal cells is limited by bioreactor surface area. One way to increase the available surface area is by growing cells as monolayers on small spheres called microcarriers, which are approximately 100-250 μm in diameter. In order for microcarrier-based cell culture to be a success, it is important to understand the kinetics of cell growth on the microcarriers. Micro-flow imaging (MFI) is a simple and powerful technique that captures images and analyzes samples as they are drawn through a precision flow cell. In addition to providing size distribution and defect frequency data to compare microcarrier lots, MFI was used to generate hundreds of images to determine cell coverage and confluency on microcarriers. Same-day manual classification of these images provided upstream cell culture teams with actionable data that informed in-process decision making (e.g. time of infection). Additionally, an automated cell coverage algorithm was developed to increase the speed and throughput of the analyses.

The purpose of this work was to investigate a potential mechanism for the inhibition of tungsten-mediated monoclonal antibody (mAb) biophysical modifications and sub-visible particle formation. A mAb formulation was incubated with tungsten polyanions in the presence and absence of the anionic surfactant and chelating agent diethylene triamine pentaacetic acid (DTPA) or the cationic surfactant cetyl trimethyl ammonium bromide (CTAB). Formulation was characterized by pH, UV-Vis spectroscopy, size exclusion chromatography, intrinsic tryptophan/tyrosine fluorescence, and micro-flow imaging. We conclude that the formulation excipient and cationic surfactant CTAB effectively inhibits biophysical modifications and sub-visible particle formation.