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Determination of the size, density, and mass of viral particles can provide valuable information to support process and formulation studies in clinical development. Analytical ultracentrifugation (AUC), as a first principal method, has been shown to be a beneficial tool for the characterization of the non-enveloped adeno associated virus (AAV). Here, we demonstrate the suitability of AUC for the challenging characterization of a representative for enveloped viruses, which usually are expected to exhibit higher dispersity than non-enveloped viruses. Specifically, the vesicular stomatitis virus (VSV)-based oncolytic virus VSV-GP was used to evaluate potential occurrence of non-ideal sedimentation by testing different rotor speeds and loading concentrations. The partial specific volume was determined via density gradients and density contrast experiments. Additionally, nanoparticle tracking analysis (NTA) was used to determine the hydrodynamic diameter of VSV-GP particles to calculate their molecular weight via the Svedberg equation. Overall, this study demonstrates the applicability of AUC and NTA for the characterization of size, density, and molar mass of an enveloped virus, namely VSV-GP.

The knowledge of thermodynamic properties for novel electrolyte formulations is of fundamental interest for industrial applications as well as academic research. Herewith, we present an artificial neural networks (ANN) approach for the prediction of solvation energies and entropies for distinct ion pairs in various protic and aprotic solvents. The considered feed-forward ANN is trained either by experimental data or computational results from conceptual density functional theory calculations. The proposed concept of mapping computed values to experimental data lowers the amount of time-consuming and costly experiments and helps to overcome certain limitations. Our findings reveal high correlation coefficients between predicted and experimental values which demonstrate the validity of our approach.

The murine polyomavirus encodes three structural proteins, VP1, VP2 and VP3, which together form the viral capsid. The outer shell of this capsid is composed of the major capsid protein VP1, the inner shell consists of VP2 and its N-terminally truncated form VP3. These two minor capsid proteins interact with their identical C-terminal part in the central cavity of VP1 pentamers, building the capsid assembly unit. While the VP1 structure and functions are well studied, VP2 and VP3 are poorly understood. In order to get a detailed insight into the structure and function of the minor capsid proteins, they were produced recombinantly in Escherichia coli as inclusion bodies and refolded in vitro. The success of refolding was strictly dependent on the presence of detergent in the refolding buffer. VP2 and VP3 are monomeric and their structures exhibit a high α-helical content. The function of both proteins could be monitored by complex formation with VP1. Furthermore, we could demonstrate a hemolytic activity of VP2/VP3 in vitro, which fits well into a postulated membrane interaction of VP2 during viral infection.