Abstract
Current techniques for monitoring glucose and lactate concentrations in cell culture media require invasive and tedious handling of the sample for sterile media removal and nutrient replacement. Even though in situ or ex situ analyte monitoring systems have been tried for on-line measurement, they suffer from difficulties including the inability to keep them sterile, their limited lifetime, and their lack of stability. In order to optimize cell culture growth in bioreactors, biosensors must be developed that are capable of monitoring cell culture parameters such as analyte concentration and cell concentration non-invasively and continuously. For this research, noninvasive determinations of glucose and lactate in cell culture media were investigated using near-infrared spectroscopy across the 2.0-2.5 mm spectral region. A system was developed using a Fourier Transform Infrared (FT-IR) spectrometer and optical fibers to characterize glucose and lactate absorbance spectra in cell culture media from hybridoma cell culture. Partial least squares (PLS) regression has been used to extract the analyte-dependent information and to build a successful multivariate calibration model. Calibration, using a combination of spectra from cell culture media and spiked sample media mixtures, was performed and applied to an independent validation data set, producing a prediction error of 1.7 % and 9.8 % for glucose and lactate, respectively. In addition, a noninvasive optical cell density monitoring system based on a laser turbidity sensor was developed. The total cell concentration predicted with optical method was in excellent agreement with off-line cell counting data. The results from the two experiments suggest that such analyte concentration and laser turbidity systems could potentially be used for on-line monitoring and control of animal cell cultivations in a bioreactor.
Lee, Seung Joon (2003). Near-infrared approaches for cell culture monitoring. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2003 -THESIS -L443.