FLUX-DEPENDENT TRANSMISSION OF RNA THROUGH ULTRAFILTRATION MEMBRANES

Open Access
Author:
Berman, Scott W
Area of Honors:
Chemical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Andrew Zydney, Thesis Supervisor
  • Michael John Janik, Honors Advisor
Keywords:
  • ultrafiltration
  • RNA
  • membrane
  • transmission
  • RNA ultrafiltration
  • Biomax
  • Durapore
  • concentration polarization
Abstract:
Recent studies of DNA ultrafiltration have demonstrated the potential for vastly improving the performance of membrane-based DNA separations by controlling the pore morphology to pre-stretch the DNA prior to filtration through the very small pores of the ultrafiltration membrane. This pre-stretching leads to an increase in DNA transmission and a reduction in membrane fouling. The objective of this thesis was to determine whether a similar approach could be used to enhance the performance of RNA ultrafiltration given the growing interest in RNA-based therapies. Experiments were performed in a stirred ultrafiltration cell using polyethersulfone Biomax membranes. Data were obtained with asymmetric membranes with the flow in either the normal (tight side facing the feed) or reverse orientations as well as with composite membrane structures created by placing a symmetric 0.22 µm pore size Durapore membrane on top of a small pore size ultrafiltration membrane. Transmission through the 100 kDa nominal molecular weight cutoff membrane was very high in both orientations, reflecting the smaller size and greater flexibility of RNA compared to DNA. RNA transmission through the 30 kDa membrane was much greater when operated with the reverse orientation, although it was not possible to clearly determine if this increase in transmission was due to pre-stretching of the RNA or to concentration polarization effects in the support structure. The results do suggest that the ultrafiltration performance for RNA separations can potentially be enhanced by controlling the underlying pore morphology of the membrane.