Prediction and characterization of the stability enhancing effect of the Cherry-Tag™ in highly concentrated protein solutions by complex rheological measurements and MD simulations.

Solution stability attributes are one of the key parameters within the production and launching phase of new biopharmaceuticals. Instabilities of active biological compounds can reduce the yield of biopharmaceutical productions, and may induce undesired reactions in patients, such as immunogenic rejections. Protein solution stability thus needs to be engineered and monitored throughout production and storage.

Root cause investigation of deviations in protein chromatography based on mechanistic models and artificial neural networks.

In protein chromatography, process variations, such as aging of column or process errors, can result in deviations of the product and impurity levels. Consequently, the process performance described by purity, yield, or production rate may decrease. Based on visual inspection of the UV signal, it is hard to identify the source of the error and almost unfeasible to determine the quantity of deviation.

Model-Based Investigation on the Mass Transfer and Adsorption Mechanisms of Mono-Pegylated Lysozyme in Ion-Exchange Chromatography.

Recent studies highlighted the potential of PEGylated proteins to improve stabilities and pharmacokinetics of protein drugs. Ion-exchange chromatography (IEX) is among the most frequently used purification methods for PEGylated proteins. However, the underlying physical mechanisms allowing for a separation of different PEGamers (proteins with a varying number of attached PEG molecules) are not yet fully understood.

Estimation of adsorption isotherm and mass transfer parameters in protein chromatography using artificial neural networks.

Mechanistic modeling has been repeatedly successfully applied in process development and control of protein chromatography. For each combination of adsorbate and adsorbent, the mechanistic models have to be calibrated. Some of the model parameters, such as system characteristics, can be determined reliably by applying well-established experimental methods, whereas others cannot be measured directly.

Effect of PEG molecular weight and PEGylation degree on the physical stability of PEGylated lysozyme.

During production, purification, formulation, and storage proteins for pharmaceutical or biotechnological applications face solution conditions that are unfavorable for their stability. Such harmful conditions include extreme pH changes, high ionic strengths or elevated temperatures. The characterization of the main influencing factors promoting undesired changes of protein conformation and aggregation, as well as the manipulation and selective control of protein stabilities are crucially important to biopharmaceutical research and process development.

Strategy for assessment of the colloidal and biological stability of H1N1 influenza A viruses.

Current influenza vaccines are mostly formulated as liquids which requires a continuous cold chain to maintain the stability of the antigen. For development of vaccines with an increased stability at ambient temperatures, manifold parameters and their influences on the colloidal stability and activity of the antigen have to be understood. This work presents a strategy to examine both, the colloidal stability and the remaining biological activity of H1N1 influenza viruses under various conditions after an incubation of 40 days.

Quantification of PEGylated proteases with varying degree of conjugation in mixtures: An analytical protocol combining protein precipitation and capillary gel electrophoresis.

PEGylation, i.e. the covalent attachment of chemically activated polyethylene glycol (PEG) to proteins, is a technique commonly used in biopharmaceutical industry to improve protein stability, pharmacokinetics and resistance to proteolytic degradation.

Downstream process development strategies for effective bioprocesses: Trends, progress, and combinatorial approaches.

The biopharmaceutical industry is at a turning point moving toward a more customized and patient-oriented medicine (precision medicine). Straightforward routines such as the antibody platform process are extended to production processes for a new portfolio of molecules. As a consequence, individual and tailored productions require generic approaches for a fast and dedicated purification process development.

High-throughput process development of an alternative platform for the production of virus-like particles in Escherichia coli.

The production of safe vaccines against untreatable or new diseases has pushed the research in the field of virus-like particles (VLPs). Currently, a large number of commercial VLP-based human vaccines and vaccine candidates are available or under development. A promising VLP production route is the controlled in vitro assembly of virus proteins into capsids.

High-throughput micro-scale cultivations and chromatography modeling: Powerful tools for integrated process development.

Upstream processes are rather complex to design and the productivity of cells under suitable cultivation conditions is hard to predict. The method of choice for examining the design space is to execute high-throughput cultivation screenings in micro-scale format. Various predictive in silico models have been developed for many downstream processes, leading to a reduction of time and material costs.

Influence of binding pH and protein solubility on the dynamic binding capacity in hydrophobic interaction chromatography.

Hydrophobic interaction chromatography (HIC) is one of the most frequently used purification methods in biopharmaceutical industry. A major drawback of HIC, however, is the rather low dynamic binding capacity (DBC) obtained when compared to e.g.

Integrated development of up- and downstream processes supported by the Cherry-Tag™ for real-time tracking of stability and solubility of proteins.

Product analytics is the bottleneck of most processes in bioprocess engineering, as it is rather time-consuming. Real-time and in-line product tracing without sample pre-treatment is only possible for few products. The Cherry-Tag™ (Delphi Genetics, Belgium) which can be fused to any target protein allows for straightforward product analytics by VIS absorption measurements.