Cell culture media are complex products that are inherently difficult to analyze. Yet, media analysis is critical for assuring product quality. A group at National University of Ireland-Galway led by Alan Ryder, Ph.D., is investigating rapid, “holistic” fluorescence analysis for screening commercially used cell culture media.
“Holistic means taking on overall measurement of the media, rather than going down the separations route and identifying or quantifying every component,” Dr. Ryder explains.
His group has been working with Bristol-Myers Squibb (BMS) and other leading biomanufacturers on the technique, which is designed for Chinese hamster ovary (CHO) cell cultures. Eventually, it will become available to all biotech companies.
The technique uses readily available fluorescence instrumentation, costing about $20,000, and MATLAB, a fourth-generation engineering software package from MathWorks (www.mathworks.com). It further relies on chemometric analysis such as multiway robust principal component analysis (MROBPCA), n-way partial least-squares discriminant analysis, and regression (NPLS-DA).
MROBPCA assesses data variance, determines its statistical significance, and seeks to understand the source of the spectral variation. “If the variation is significant we use NPLS-DA to build identification models to discriminate different media based on their spectra, or NPLS to quantify the relationship between spectral data variation and production data, for example yield.”
This approach was developed empirically, by correlating samples of cell culture media from BMS with productivity measurements of manufacturing batches employing those specific media.
These sophisticated statistical tools are required since, while it identifies medium components through their natural fluorescence, this approach does not quantify ingredients individually. Rather, it provides a fluorescence map or signature that quantifies media quality and predicts its success. “We look at overall changes, not specific components.” Dr. Ryder claims the technique predicts volumetric productivity to within 0.13 g/L.
Chromatographic analysis of media components is possible but extremely time-consuming and expensive. Dr. Ryder’s rapid, low-cost technique is suitable for screening media rapidly and then, if needed, analyzing only select formulations later by HPLC for quality or trouble-shooting purposes.
The ability to observe compositional changes in media and predict product yield before production has enormous potential, Dr. Ryder says. “It should effectively eliminate one of the major process variables, thus leading to more consistent product quality and yield.”