Monitoring of heat- and light exposure of cell culture media by RAMAN spectroscopy: Towards an analytical tool for cell culture media quality control

Abstract

• Spectral differences in RAMAN microscpectroscopy can be leveraged to distinguish individual cell culture media. • RAMAN microspectroscopy is able to track chemical changes of glucose solutions and cell culture media upon energy input. • Light but not heat induced alterations in chemically defined cell culture media and tracked by RAMAN microspectroscopy. Cell culture media are highly complex solutions of multiple nutrients for mammalian cells and lay the foundation for enhanced quality of the expressed protein and the performance of the bioprocess. Especially for long term, large-volume continuous production processes the constant quality of media without compositional variation is desirable, despite exposure to various stress conditions like (UV)-light or (high)-temperature cannot be represented by a measurable parameter yet. In this study, chemometric analysis of non-enhanced RAMAN spectra was used to identify different cell culture media and to track accelerated degradation conditions by light or temperature in aqueous solutions of glucose and chemically defined media. To link the changes in the RAMAN spectra with cell culture parameters we used the untreated and stressed media for biophysical and biochemical measurements as well as cell culture experiments. The two tested media were exceptionally stable against heat, but showed diminished biological performance after light exposure accompanied by reduced concentrations of the key amino acids Met , His , Trp and Lys. RAMAN spectroscopy provides a rapid and non-destructive method to distinguish individual cell culture media and to find even minor differences between otherwise comparable media lots. In this study we demonstrate the suitability of RAMAN spectroscopy for identity- and quality testing of various process media as an exciting tool for implementation in quality control of bioprocessing.