Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z

Manish Kumar, Mariusz Grzelakowski, Julie Zilles, Mark Clark, Wolfgang Meier*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

498 Scopus citations

Abstract

The permeability and solute transport characteristics of amphiphilic triblock-polymer vesicles containing the bacterial water-channel protein Aquaporin Z (AqpZ) were investigated. The vesicles were made of a block copolymer with symmetric poly-(2-methyloxazoline)-poly-(dimethylsiloxane)-poly- (2-methyloxazoline) (PMOXA15-PDMS110-PMOXA15) repeat units. Light-scattering measurements on pure polymer vesicles subject to an outwardly directed salt gradient in a stopped-flow apparatus indicated that the polymer vesicles were highly impermeable. However, a large enhancement in water productivity (permeability per unit driving force) of up to ≈800 times that of pure polymer was observed when AqpZ was incorporated. The activation energy (Ea) of water transport for the protein-polymer vesicles (3.4 kcal/mol) corresponded to that reported for water-channel-mediated water transport in lipid membranes. The solute reflection coefficients of glucose, glycerol, salt, and urea were also calculated, and indicated that these solutes are completely rejected. The productivity of AqpZ-incorporated polymer membranes was at least an order of magnitude larger than values for existing salt-rejecting polymeric membranes. The approach followed here may lead to more productive and sustainable water treatment membranes, whereas the variable levels of permeability obtained with different concentrations of AqpZ may provide a key property for drug delivery applications.

Original languageEnglish (US)
Pages (from-to)20719-20724
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number52
DOIs
StatePublished - Dec 26 2007

Keywords

  • Permeability
  • Triblock copolymer
  • Water treatment

ASJC Scopus subject areas

  • General

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