In situ microscopy for on‐line characterization of cell‐populations in bioreactors, including cell‐concentration measurements by depth from focus

Abstract

A new technique is presented which allows the use of a front-end sensor head for in situ and on-line characterization of cell concentration and cell size during fermentation. An epifluorescence microscope is mounted in a port of a bioreactor viewing directly into the agitated broth. Still images from cells are generated using pulsed illumination. They are directly visualized on a monitor and used for automatic image analysis. The cell concentration and morphological information are determined by counting and evaluating the cell images with respect to their depth from focus characteristic. An in situ microscope was successfully tested during yeast fermentations and yielded results which correlated well with results from a hemocytometer. (c) 1995 John Wiley & Sons, Inc.

Optimization of Insect Cell Based Protein Production Processes - Online Monitoring, Expression Systems, Scale Up

“…In situ microscopy (ISM) is a promising tool for bioprocess monitoring in cell Since the microscope does not enclose a defined sample volume mechanically, information about the cell concentration is derived from a virtually defined volume (depth from focus -procedure [88]). Beside information regarding cell density, cell size distribution and cell morphology, the development of an in situ dark field microscope also facilitates measurement of the cell viability.…”

Online monitoring of microcarrier based fibroblast cultivations with in situ microscopy

“…In situ microscopy (Bittner et al, 1998;Brueckerhoff, 2006;Frerichs, 2000;Suhr et al, 1995) has proven to be a suitable method for real time inline monitoring in fermentation processes for different yeasts (Bittner et al, 1998;Camisard et al, 2002) and mammalian suspension cell lines Guez et al, 2004;Joeris et al, 2002). Important process parameters such as cell concentration, cell size distribution, cell volume and culture aggregation state, that is distribution into single cells, double cells and cell clusters (with more than two cells) can be measured.…”

In situ microscopy for on-line determination of biomass

“…Up to now, two types of in situ microscopes have been developed. The first one, based on epifluorescence microscopy, pulsed illumination, and an optical definition of the sample volume was presented previously in this journal (Suhr et al, 1995). The sond one, based on direct light microscopy, permanent illumination, and a mechanical definition of the sample volume, is described here.…”