Adaptation of electrospinning and electrospraying for the development of novel live virus vaccine formulations

Despite a growing interest in alternative vaccination routes, there are challenges in formulation that limit efficiency of oral or pulmonary vaccines, especially in livestock animals. Electrospinning (ES) and electrospraying offer gentle drying at room temperature, making them suitable for the formulation of biopharmaceuticals, including live virus particles. In this study, first a polyvinyl pirrolydone (PVPVA64)-based matrix system was developed and evaluated for product morphology and downstream processability to adapt the technology for virus carriage. The optimal concentration of the aqueous polymer solution was 45% for oral administration (resulting in nanofibers), and 30% for aerogenic delivery (producing nanoparticles). An automated AI tool, based on machine vision, was established for the control of particle size distribution. The study continued with the integration of three different (enveloped and non-enveloped) viruses into electrospun nanofibers, using a high-speed ES setup. PVPVA64 and polyvinyl alcohol with polyethylene oxide (PVA-PEO) were chosen as biocompatible matrix polymers, supplemented with mannitol or sucrose excipients. After optimization of the environmental conditions, changes of viral infectious titers upon production and storage were analyzed, comparing the different polymer-stabilizer combinations used. While notable variance was detected between the results of different viruses, sucrose was overall more effective in the protection of viral infectivity at the initial stage (the ES process), while mannitol had a superior protective effect during later storage. PVPVA64 supplemented with mannitol was the best combination regarding all-round stability of virus-loaded nanofibers. Using the same matrix (PVPVA64-mannitol), electrosprayed nanoparticles were also constructed to encapsulate the porcine coronavirus TGEV, where viral titers showed even higher long-term stability than in nanofibers. Our results prove the high potential of ES and electrospraying for the dry formulation of viruses. With further research, these technologies might open up new possibilities in vaccination against viral diseases of animals and humans. • High-speed electrospinning and electrospraying was adapted for live virus carriage. • A machine vision-based AI tool was developed for the control of nanoparticle size. • Viruses nanoformulated with excipients retained infectivity during construction and storage. • Virus-loaded nanofibers and nanoparticles are suitable for oral and pulmonary vaccination.