Optical Sampling in-situ Microscopy for on-line Monitoring of Animal Cell Cultures

Abstract

Cell concentration and cell vitality are key parameters to be monitored during cell cultivation processes. Common techniques used for these purposes are often based on sterile sampling and subsequent off line measurements. Extraction and preparation of samples is labour-intensive and risk-entailing. These disadvantages are avoided if the cell culture is directly inspected by using an in-situ technique, e.g. an in-situ microscope (ISM). An ISM delivers a wealth of image data which can be evaluated so as to provide automatic monitoring of the cell density and of morphological parameters as the cell-size. In-situ microscopy can either employ periodic opening and closing of a probe chamber inside the reactor or, alternatively, flash illumination and optical depth of field in order to define a virtual probe zone. Here, we describe optics and software of an advanced version of such an ISM with unprecedented resolution and frame rate. Fast collection of online-galleries of individual cell-portraits even at low cell concentrations enables online morphological analysis without sample extraction. Cell density data obtained by the ISM and traditional counting are shown in comparison, revealing the advantage of the ISM with respect to statistic deviations.