Clearance of Protein-Bound\nUremic Toxins Using Anion\nNanotraps with Record High Uptake

Traditional hemodialysis often fails to remove protein-bound\nuremic\ntoxins (PBUTs) like <i>p</i>-cresyl sulfate (<i>p</i>CS) and indoxyl sulfate (IS) due to their strong binding to human\nserum albumin, which is linked to adverse cardiovascular outcomes.\nHerein, a class of cationic polymeric networks, denoted as CPN-X6–CPN-X9,\nare reported for the efficient removal of PBUTs. The abundant imidazole-based\nnanotraps in these cationic polymeric networks confer a highly positive\ncharge density, resulting in CPN-X7 achieving a maximum sorption capacity\nof 1000.8 mg/g for <i>p</i>CS and CPN-X6 offering a maximum\nsorption capacity of 1028.4 mg/g for IS, surpassing all previously\nreported sorbents. Furthermore, CPN-X9, which is relatively hydrophobic,\nexhibits remarkable selectivity in competitive experiments involving\nlarge amount of chloride ions and serum albumin, attaining removal\nrates of up to 74% for <i>p</i>CS and 93% for IS in the\nrecycling <i>in vitro</i> dialysis mode. Meanwhile, CPN-X9\ndemonstrates excellent recyclability over five cycles, and the cationic\npolymeric network materials exhibit satisfactory hemocompatibility.\nThe sorption mechanism of the anion exchange process is fully elucidated\nand verified by density functional theory (DFT) calculations. This\nstudy provides valuable insights into enhancing the removal efficiency\nof PBUTs and presents broad prospects in the field of clinical blood\npurification.