Raman spectroscopy of complex defined media: Biopharmaceutical applications

F.R. Hajiyeva1*, N.A. Abdullayev2

1 Research Institute of Obstetrics and Gynecology, 118 Kazim Kazimzadə Str., Baku AZ1065, Azerbaijan

2 Institute of Physics, Azerbaijan National Academy of Sciences, 131 H.Javid Ave., Baku AZ1143, Azerbaijan

*For correspondence: dr.fatima79@mail.ru

Received: May 14, 2021; Received in revised form: June 12, 2021; Accepted: June 19, 2021

Hamster ovary cells were grown in a batch culture flask for 10 days in an incubator maintained with 5% CO2 and 37 °C temperature. The 2 ml supernatant was collected each day, in duplicate, and was stored in a freezer at -20 °C. Concentrations of glucose and lactate were estimated, in the supernatant, on an HPLC machine, and the same sample was used to immediately obtain the results of Raman measurements. We demonstrate the detection of glucose and lactate concentrations with high accuracy in the supernatants of hamster ovary (HO) cell culture, grown in shake flasks in batch fermentation mode, using Raman spectroscopy and explicit model-based classical least squares (CLS) algorithm. A deterministic Raman spectral library of pure components was created by acquiring Raman spectra from credible nutrient media constituents and HO cell culture metabolites. Only analyzers present with concentrations above the instrument's detection limit were included in this library. Residuals obtained after CLS analyses were used to identify missing components and to generate a revised library. An algorithmic sieve was thus, construed to obtain an appropriate Raman spectral library from a complex chemical mixture that is well-defined but an industrial secret. High performance liquid chromatography (HPLC) was used to provide reference glucose and lactate concentrations. We demonstrate the detection of glucose and lactate concentrations in the supernatants of HO cell culture using Raman spectroscopy and explicit model-based CLS analysis.

Keywords: Raman spectroscopy, bioreactors, classical least squares, glucose detection, lactate detection