Driving forces in aqueous two-phase systems for vaccine development

Michigan Technological University, Houghton MI

Investigators

Abstract

Worldwide, there is a need for less expensive vaccines. To achieve better vaccine coverage, vaccine production processes need to be low-cost and allow for continuous operation, which is not possible with current vaccine production technology. A primary objective of this project will be to explore aqueous two-phase systems (ATPSs) to fulfill the need for new viral particle purification processes that could reduce the cost of vaccines and be run as a continuous operation. ATPS could also reduce the development time for a new vaccine, allowing for pandemic vaccines to come to market sooner. In addition to vaccines, a better understanding of ATPS could aid in future cell separations for advanced cell therapeutics. The significant increase in the manufacturing of vaccines worldwide has created an opportunity to re-think current vaccine manufacturing methods. Currently, ATPS is not used industrially due to the large number of variables that need to be determined during the short development timelines that are imposed on vaccine process development teams. The long-term goal of this project is to determine the dominant forces in ATPS for the separation of viral particles to aid industrial adoption. Preliminary work has indicated that hydrophobicity is the dominant force in viral particle separation in a polyethylene glycol (PEG)-citrate ATPS. The expected outcome is to reduce the variables tested in the development of viral particle purification processes and provide a framework to implement ATPS separations. Affinity ATPS will be used to maintain a constant driving force for the virus to partition to the PEG-rich phase. With this constant driving force established, the PEG molecular weight will be changed and the viral separation will be compared to the constant affinity driving force. Osmolytes will be added to the PEG-citrate ATPS to increase the hydrophobicity and to separate the hydrophobicity driving force from the increase in surface tension that restricts virus recovery. All of the work will be integrated by providing a framework using the Design of Experiments (DOE) approach to isolate the hydrophobic effect of viral ATPS. Results of the project will provide a detailed understanding of the driving forces in ATPS that will allow easier implementation of this method for viral particle manufacturing. Through this approach the PI will systematically determine the key variables that control viral particle separations. An important goal is to determine the effect of hydrophobicity on the separation of viruses and to determine the magnitude of the hydrophobic force on the ATPS separation. In terms of the broader impacts, the fundamental knowledge gained from this work may guide the design of low-cost separation and manufacturing processes that will increase access to vaccines worldwide. Importantly, the experimental design framework can be applied to other large biomolecules such as those employed in viral gene therapies and cell therapies. Outreach to high school students will be conducted through Summer Youth Programs (SYP). The SYP activity will explore the separation of gold nanoparticles in ATPS and teach students about bioprocessing, model systems, and the need for control in ATPS. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.