Department of Energy Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
School of Biomedical Engineering, Korea University, Seoul, 02841, Republic of Korea.
Adv Sci (Weinh). 2021 Oct;8(20):e2101882. doi: 10.1002/advs.202101882. Epub 2021 Aug 16.
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 h bar at 8 bar with a 1000-ppm NaCl feed solution, which surpasses the upper-bound line of current state-of-the-art membranes.
水通道蛋白（AQP）是天然的水分子通道，一直以来都被积极研究以克服传统反渗透膜的局限性。通过将携带水通道蛋白的红细胞膜（RBCM）囊泡固定在氧化石墨烯（GO）上来设计基于 AQP 的仿生高压反渗透膜。根据 RBCM 上的整合素与 GO 表面上的精氨酸-甘氨酸-天冬氨酸（RGD）配体之间的分子识别，将具有 AQP 的 RBCM 整合到 GO 中。GO 预先通过 Glycine-Arginine-Glycine-Aspartate-Serine 肽进行功能化，以捕获 RBCM。RBCM 通过 RBCM 整合素与 RGD 配体之间的材料特异性相互作用插入 GO 薄片之间，从而确保 GO 中的通道/缺陷有足够的覆盖率，以使 AQP 充分发挥作用。整合的 AQP 并没有完全固定在 GO 上，因为连接是由整合素-RGD 对介导的，并且在没有来自固体基底的摩擦阻碍的情况下，保证了适当的 AQP 灵活性以实现适当的功能。GO-RBCMs 结合的完整性可以为承受高压反渗透条件以处理大量水提供机械强度。这种仿生膜在 8 巴时，在 1000ppm NaCl 进料溶液下，对 99.1%的 NaCl 具有排斥性，水通量为 7.83 L m h bar，超过了当前最先进膜的上限线。
