A microscale yeast cell disruption technique for integrated process development strategies.

Miniaturizing protein purification processes at the microliter scale (microscale) holds the promise of accelerating process development by enabling multi-parallel experimentation and automation. For intracellular proteins expressed in yeast, small-scale cell breakage methods capable of disrupting the rigid cell wall are needed that can match the protein release and contaminant profile of full-scale methods like homogenization, thereby enabling representative studies of subsequent downstream operations to be performed. In this study, a noncontact method known as adaptive focused acoustics (AFA) was optimized for the disruption of milligram quantities of yeast cells for the subsequent purification of recombinant human papillomavirus (HPV) virus-like particles (VLPs).

An automated microscale chromatographic purification of virus-like particles as a strategy for process development.

The development of fermentation processes for recombinant vaccines requires optimizing expression while maintaining high product quality. Changes to cell fermentation conditions are typically evaluated following cell disruption, with expression levels quantified by immunoassay, liquid chromatography or enzyme activity. However, assay titres do not always predict the effects that intracellular aggregation, proteolysis, post-translational modifications and differences in relative impurity levels can have on purification yield and product purity.

An automated homogeneous method for quantifying polysorbate using fluorescence polarization.

An automated fluorescence polarization (FP) assay has been developed for the quantitation of polysorbate in bioprocess samples. Using the lipophilic probe 5-dodecanoylaminofluorescein (DAF), polysorbate concentrations above the critical micelle concentration can be quantified by the FP increase that results when DAF inserts into the detergent micelles. The specificity, accuracy, and precision of this assay were defined for samples obtained from vaccine purification processes.