“Holographic Imaging of Insect Cell Cultures: Online Non-Invasive Monitoring of Adeno-Associated Virus Production and Cell Concentration”

This work shows that DHM can be implemented for online monitoring of Sf9 concentration and viability, as well as for monitoring product titer (AAV) or culture progression in lytic systems. Therefore, it a valuable tool to support the time of harvest decision and for establishing controlled feeding strategies.

The insect cell-baculovirus vector system has become one of the favorite platforms for viral vector expression for vaccination and gene therapy purposes. Since it is a lytic system, it is essential to balance maximum recombinant product expression with harvest time, minimizing product exposure to detrimental proteases. With this purpose, new bioprocess monitoring solutions are needed to accurately estimate culture progression. For this study, we used online digital holographic microscopy (DHM) to monitor bioreactor cultures of Sf9 insect cells.

Figure 4. Time-course profiles for selected D3HM attributes. The growth batch is in black, while the infected batch is in grey. Measurements were obtained every 30 min. (A) Intensity Average Contrast; (B) Intensity Average Entropy; (C) Intensity Average Intensity; (D) Phase Skewness; (E) Phase Correlation; (F) Intensity Correlation; (G) Optical Height Minimum; (H) Optical Volume; (I) Peak Area Normalized; (J) Peak Height.