(389c) Membrane Selection Towards Advancing Nanoparticle Biotherapeutic Purification for Viral Vector Bioprocessing Applications

As use of nanoparticles as delivery mechanisms, such as viral vectors, increase exponentially, robust downstream purification techniques become widely needed. The most universally used viruses for viral vectors today are lentivirus, adenovirus, and adeno-associated virus (AAV). These vectors are used as delivery systems for gene therapies, oncolytic therapies, and vaccines. Current purification methods for these vectors rely solely on batch system processes such as ultracentrifugation and diffusion limited chromatography methods. While these methods have provided high recovery yields of viral vectors, they are slow, cost intensive, and have scalability limitations. A proposed solution to these production issues was a membrane filtration technique for the purification of viral vectors. The objective of this study was to examine fouling, retention, and recovery rates of nanoparticles through membranes with different pore sizes, thicknesses, tortuosity, porosity, and surface characteristics. Data were obtained utilizing 20nm fluorescently labeled silica nanoparticles as a model for AAV vectors (18-24nm). The concentration of the silica nanoparticles used mimicked typically bioreactor harvest compositions of AAV viral vectors (10³ particles/mL). Larger silica nanoparticles (500nm) and bovine serum albumin (BSA) modeled other impurities in the bioreactor harvest system. Polyvinylidene fluoride (PVDF), polycarbonate, and cellulosic membranes with pore sizes ranging from 45nm-450nm were used. Optimal membrane characteristics were determined. These characteristics provided the highest recovery of the synthetic AAV viral vector model while maximizing efficiency. A thin, isoporous membrane was found to be the optimal membrane for this application. This type of membrane allowed for minimal pore entrapment of the synthetic AAV viral vector model, thus the highest recovery. These results provide a framework into membrane-based nanoparticle filtration needed for nanoparticle therapeutics such as AAV viral vectors. This research was supported by the NSF EPSCoR Track 2.