Pressure Effects on Virus Retention with the Ultipor Dv20 Membrane
Open Access
- Author:
- Woods, Melissa Ann
- Graduate Program:
- Chemical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 04, 2013
- Committee Members:
- Andrew Zydney, Thesis Advisor/Co-Advisor
Kristen Ann Fichthorn, Thesis Advisor/Co-Advisor
Manish Kumar, Thesis Advisor/Co-Advisor - Keywords:
- Virus filtration
bioprocessing
virus clearance
bacteriophage - Abstract:
- Virus filtration is a well-established method for minimizing the inherent risk of viral contamination in the production of both therapeutic proteins and potable water. Although virus filters remove viruses primarily on the basis of size, the extent of virus retention can vary significantly over the course of the filtration or in response to changes in operating conditions. Several studies have reported a significant decline in virus retention during constant pressure virus filtration with certain filters. More recently, limited experiments showed that a temporary release in the transmembrane pressure caused a significant increase in transmission of both porcine parvovirus (PPV) and encephalomyocarditis virus (EMCV). However, there is currently no detailed understanding of the factors controlling this phenomenon or the underlying physical basis for the observed increase in transmission. The objective of this work was to obtain quantitative data for the effects of a pressure release on filtration of a model bacteriophage through the Ultipor DV20 membrane. In addition, confocal microscopy was employed to visualize the capture of fluorescently labeled bacteriophage within the membrane. Results showed a transient increase in bacteriophage transmission by approximately a factor of 10 (one log) immediately after the pressure release, with the transmission then decreasing back to a value similar to that in a control experiment. Confocal microscopy showed that the pressure release caused the bacteriophage to migrate further into the depth of the membrane. The data were analyzed using a modified version of an internal polarization model that accounts for virus accumulation in the upper (reservoir) zone within the DV20 membrane. These results provide important insights into the factors controlling virus retention during virus filtration.