Proposal Number: CTS-0456831 Principal Investigator: Ranil Wickramasinghe Institution: Colorado State University
The objective of this project is to develop adsorptive membranes as a new, high efficiency unit operation for the recovery and purification of the products of modern molecular biology, such as plasmid DNA, large proteins, and viruses and viral vectors. Novel, high-throughput membranes will be developed as alternative chromatographic supports. Since the feed is pumped through the membrane pores, pore diffusion can be eliminated, leading to binding capacities that are independent of flow rate. As the capacities of adsorptive membranes are equivalent to or greater than those of chromatographic resins, the membrane volume required will be much less than current packed-bed volumes. The research focuses on virus and viral vector purification for gene therapy and vaccine production, as well as virus clearance, which is essential in the production of antibodies and biopharmaceuticals from cell cultures. Five objectives will be pursued: 1) Commercially available membranes and functionalized membranes will be characterized to determine their porosities, pore-size distributions and surface chemistries. Optimized conditions for virus adsorption and the elution of bound viruses will be determined. 2) Non-track-etched membranes will be modified by graft polymerization from the membrane surface. 3) Track-etched membranes will be modified by graft polymerization from the membrane surface. Comparing virus adsorption by track-etched and non-track-etched membranes will provide useful information on the optimum membrane morphology for virus adsorption. 4) Copolymer grafts comprising an ion-exchange monomer and a "spacer" co-monomer will be grown from the membrane surfaces to examine how spatial distribution of ion-exchange sites affects virus binding. 5) A predictive model of practical value for virus clearance will be developed. This model will provide insights into adsorption of viruses not tested here and will include the effects of membrane pore-size distribution. In terms of the broader impacts, the PIs will work with the directors of programs at their institutions that focus on increasing participation in research by undergraduates from underrepresented groups. NSF supplemental award mechanisms such as REU, RET, and international supplements will be sought to support summer undergraduate researchers and teachers in residence and to strengthen the international collaboration. Applications of this research could benefit society by providing breakthrough technologies in bio-purifications.
