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Abstract: SA-PO418

Molecular Sieving via Conformational Flexing During Frictionless Flow in Slippery Carbon Nanotube Membranes for Hemodialysis

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Kidambi, Piran, Vanderbilt University, Nashville, Tennessee, United States
  • Cheng, Peifu, Vanderbilt University, Nashville, Tennessee, United States
  • Ferrell, Nicholas J., The Ohio State University, Columbus, Ohio, United States
  • Öberg, Carl Mikael, Lunds Universitet, Lund, Sweden
  • Buchsbaum, Steven F., Lawrence Livermore National Laboratory, Livermore, California, United States
  • Jue, Melinda L., Lawrence Livermore National Laboratory, Livermore, California, United States
  • Wang, Dan, The Ohio State University, Columbus, Ohio, United States
  • Roy, Shuvo, University of California San Francisco, San Francisco, California, United States
  • Fornasiero, Francesco, Lawrence Livermore National Laboratory, Livermore, California, United States
  • Fissell, William Henry, Vanderbilt University Medical Center, Nashville, Tennessee, United States

Size selective molecular separation offer transformative advances in hemodialysis. The classic trade-off between selectivity and permeability necessitates larger membrane areas (larger kits) and high pressures in conventional dialysis membranes, which limits progress towards implantable/wearable alternatives. Here, vertically aligned nanoscale capillaries embedded in a polymer matrix present new possibilities.


Vertically aligned carbon nanotubes (CNTs) forests were synthesized via chemical vapor deposition with precise diameter control via catalyst engineering and the space between was filled with paralyene. A microporous silicon support was used as a backing plate and the membranes mounted into a custom-built filtration cell. Hydraulic permeability was assessed via gravimetric flow rates at different transmembrane pressures. The transport of fluorescently labeled polydisperse Ficoll, either in phosphate-buffered saline (PBS) or bovine blood plasma was used to evaluate the size-selectivity. Ficoll concentrations were analyzed using size-exclusion chromatography.


The synthesized CNT membranes membrane exhibited a cut-off ~6nm for Ficoll in PBS as well as bovine blood plasma. We measured a hydraulic permeability ~102.3 ml h-1 m-2 mm Hg-1 in comparison to ~30 ml h-1 m-2 mm Hg-1 reported in the literature for conventional high flux dialyzers. The CNT membranes allow for near complete passage of ~2 nm Ficoll molecules (Figure), which is similar to the approximate size of hemodialysis relevant small/middle molecules, e.g. b2 microglobulin, while maintain clinically acceptable levels of Albumin loss.


The synthesized CNT membranes showed enhanced middle molecule clearance as well as higher hydraulic permeability compared to conventional hemodialysis membranes.


  • Other U.S. Government Support