An ultra scale-down characterization of low shear stress primary recovery stages to enhance selectivity of fusion protein recovery from its molecular variants.

Fusion proteins offer the prospect of new therapeutic products with multiple functions. The primary recovery is investigated of a fusion protein consisting of modified E2 protein from hepatitis C virus fused to human IgG1 Fc and expressed in a Chinese hamster ovary (CHO) cell line. Fusion protein products inevitably pose increased challenge in preparation and purification.

Identifying analytics for high throughput bioprocess development studies.

In recent years, high throughput screening (HTS) studies have been increasingly employed as an integral element of bioprocess development activities. These studies are often limited by an analytical bottleneck; they generate multiple samples for analysis and the available analytical methods cannot always cope with the added analytical burden. A potential solution to this challenge is offered by the deployment of appropriate analytics.

Strategic Assay Selection for analytics in high-throughput process development: case studies for downstream processing of monoclonal antibodies.

During bioprocess development a potentially large number of analytes require measurement. Selection of the best set of analytical methods to deploy can reduce the analytical requirements for process investigation but currently relies on application of heuristics. This paper introduces a generic methodology, Strategic Assay Selection, for screening a large number of analytical methods to produce a subset of analytics that best suit high-throughput studies.

Large-scale plasmid DNA processing: evidence that cell harvesting and storage methods affect yield of supercoiled plasmid DNA.

The effect of bacterial-cell centrifugation and handling on the initial stages of plasmid processing was investigated. Escherichia coli cells containing either a 6 or 20 kb plasmid were grown in 75- and 450-litre bioreactors, and the process yield of the early recovery stages was characterized in terms of SC pDNA (supercoiled plasmid DNA) recovered. In all cases, the cells were totally recovered using either a continuous-feed, intermittent-solids-discharge, disc-stack centrifuge or a continuous-feed, batch-discharge, solid-bowl centrifuge.

Prediction of shear damage of plasmid DNA in pump and centrifuge operations using an ultra scale-down device.

Supercoiled circular (SC) plasmid DNA is often subjected to fluid stress in large-scale manufacturing processes. It is thus important to characterize the engineering environment within a particular unit operation as well as within the associated ancillary equipment during process design for plasmid DNA manufacture so as to avoid shear-induced degradation of the SC isoform, which would compromise product efficacy in therapeutic applications. In the past few years, ultra scale-down (USD) tools were developed within our laboratory to mimic the engineering environments experienced by biomolecules within a range of manufacturing-scale ancillary, primary recovery, and purification operations, using milliliter quantities of material.

Bioprocess engineering issues that would be faced in producing a DNA vaccine at up to 100 m3 fermentation scale for an influenza pandemic.

The risk of a pandemic with a virulent form of influenza is acknowledged by the World Health Organization (WHO) and other agencies. Current vaccine production facilities would be unable to meet the global requirement for vaccine. As a possible supplement a DNA vaccine may be appropriate, and bioprocess engineering factors bearing on the use of existing biopharmaceutical and antibiotics plants to produce it are described.