Aquaporin‐Incorporated Graphene‐Oxide Membrane for Pressurized Desalination with Superior Integrity Enabled by Molecular Recognition

Abstract

Aquaporins (AQPs), the natural water channel, have been actively investigated for overcoming the limitations of conventional desalination membranes. An AQP-based biomimetic high-pressure desalination membrane is designed by tethering AQP-carrying red blood cell membrane (RBCM) vesicles onto graphene oxide (GO). RBCMs with AQPs are incorporated into GO based on the molecular recognition between the integrin of RBCM and Arginine-Glycine-Aspartate (RGD) ligand on the GO surface. GO is pre-functionalized with the Glycine-Arginine-Glycine-Aspartate-Serine peptide to capture RBCMs. RBCMs are inserted between GO flakes through the material-specific interaction between integrin of RBCM and RGD ligand, thus ensuring sufficient coverage of channels/defects in the GO for the full functioning of the AQPs. The incorporated AQPs are not completely fixed at the GO, as tethering is mediated by the integrin-RGD pair, and suitable AQP flexibility for appropriate functioning is guaranteed without frictional hindrance from the solid substrate. The integrity of the GO-RBCMs binding can provide mechanical strength for enduring high-pressure reverse-osmosis conditions for treating large amounts of water. This biomimetic membrane exhibits 99.1% NaCl rejection and a water permeance of 7.83 L m −2 h −1 bar −1 at 8 bar with a 1000-ppm NaCl feed solution, which surpasses the upper-bound line of current state-of-the-art membranes.

Fundamental Understanding of Ultrathin, Highly Stable Self-Assembled Liquid Crystalline Graphene Oxide Membranes Leading to Precise Molecular Sieving through Non-equilibrium Molecular Dynamics

“…The membrane showed stable and consistent water permeance for a stretch of 1 week. This study was instrumental toward confirming the excellent mechanical integrity of our fabricated membranes …”

“…This study was instrumental toward confirming the excellent mechanical integrity of our fabricated membranes. 35 The efficient dye rejection abilities via these membranes were evaluated using a cationic dye (Methylene Blue, MB), an anionic dye (Congo Red, CR), and a mixture of both dyes. It can be seen from Figure 6c that the membrane showed 99% and 98% rejection for both dye molecules and for the mixture of dyes.…”

PCR-like performance of rapid test with permselective tunable nanotrap

“…We prepare BEETLES 2 with a combination of red blood cell membranes (RBCMs) and nanoporous anodic aluminum oxide (AAO). The combination of high AAO flux and an aquaporin (AQP) water channel, unlike size-based AAO membrane enrichment 27 , 28 , allows fast water transport with additional permselectivity within 3 min, achieving enrichment of SARS-CoV-2 viruses, nucleocapsid (N) proteins, and immunoglobulin G (IgG) antibodies. The limit of detection (LOD) is enhanced up to 20-fold.…”