Facilitated Water Transport through Graphene Oxide Membranes Functionalized with Aquaporin‐Mimicking Peptides

Abstract

Water purification by membranes is widely investigated to address concerns related to the scarcity of clean water. Achieving high flux and rejection simultaneously is a difficult challenge using such membranes because these properties are mutually exclusive in common artificial membranes. Nature has developed a method for this task involving water-channel membrane proteins known as aquaporins. Here, the design and fabrication of graphene oxide (GO)-based membranes with a surface-tethered peptide motif designed to mimic the water-selective filter of natural aquaporins is reported. The short RF8 (RFRFRFRF, where R and F represent arginine and phenylalanine, respectively) octapeptide is a concentrated form of the core component of the Ar/R (aromatic/arginine) water-selective filter in aquaporin. The resulting GO-RF8 shows superior flux and high rejection similar to natural aquaporins. Molecular dynamics simulation reveal the unique configuration of RF8 peptides and the transport of water in GO-RF8 membranes, supporting that RF8 effectively emulates the core function of aquaporins.

Protein–protein interactions in AQP regulation – biophysical characterization of AQP0–CaM and AQP2–LIP5 complex formation

“…Based on the solution found in nature, articial water channels seek to mimic the highly efficient and selective water transport mechanism of AQPs, thereby generating a novel strategy for advanced water purication lters. [13][14][15] We envisage that detailed knowledge of the specic molecular interactions that are able to control water transport through AQPs in the cell could enable the development of water lters with completely new regulatory properties, allowing articial water channels to be controlled using biomimetic solutions.…”

“…Such knowledge could be used to design drugs that target AQP complexes in diseases where AQP regulation is disturbed. Furthermore, an increased understanding of the specic molecular interactions that regulate AQP function in vivo may have implications for the development of articial water channels for water purica-tion purposes [13][14][15] with novel regulatory properties. In this study we explore the interaction between AQP0 and CaM as well as AQP2 and the lysosomal trafficking regulatory protein LIP5 (LYST-interacting protein 5), thereby exemplifying protein-protein interactions involved in AQP gating and trafficking respectively.…”

2D Laminar Membranes for Selective Water and Ion Transport

“…The amino groups in the peptide, because of special sequence, showed ion recognizable capability toward Co 2+ and Ni 2+ and permitted them to permeate five times faster than Cu 2+ . In a similar fashion, another artificial peptide was materialized and tethered in GO channels by Lee et al to act as a water‐selective filter . Two specific amino acids, arginine (R) and phenylalanine (F), were programmed in the peptide to mimic the core function of water‐affinitive aquaporin in biological environments.…”

Bioinspired nano-ordered liquid membrane for precise molecular separation

“…27,28 The integration of AQP within the matrix of polymer or graphene oxide membranes is the direct method to construct bioinspired membranes. 29,30 However, the di cult manipulation of orientation and connectivity of AQPs, their intricate structure, high cost and low stability severely hinder further applications of AQP based membranes. 27 Recently, arti cial channel-based bioinspired membranes that mimic the structures and functions of cellular membranes have emerged and are more appealing due to their easy fabrication and high stability, which can be divided into two categories based on their channel construction: unimolecular channel membrane and self-assembling channel membrane.…”