Zwitterionic polymers as high-performance coatings for hemoperfusion adsorbents and their chemisorption of protein-bound toxins through computational simulations

It remains a challenge for commercial hemoperfusion adsorbents to efficiently remove multiple protein-bound toxins in the clinical treatment of liver and kidney failure. Here, polystyrene divinylbenzene microspheres (PS-DVB) were surface-modified by poly(carboxybetaine methacrylate) (poly-CBMA) through controlled poly-merization, named PCBMA. PS-DVB served as a supporting backbone and provided enormous specific surface, while a layer of the poly-CBMA aimed at efficiently removing various toxins and attaining better biocompati-bility. After modification, the mesoporous analysis revealed a high specific surface area of 527 m2/g. More notably, compared with PS-DVB, PCBMA showed an 830%, 130%, and 26% increase in the adsorption capacity of p-cresol sulfate (PCS), indoleacetic acid (IAA), and bilirubin (BR), respectively, in the presence of 40 g/L bovine serum albumin. Further molecular dynamics simulations and DFT calculations showed that poly-CBMA exhibited stronger intermolecular forces for all three toxins. The hydrogen bonds formed between the nega-tively charged carboxylate ions from PCBMA contributed to its excellent adsorption performance. This study not only provides a new idea to study the adsorption mechanism of toxins by zwitterionic polymers but also dem-onstrates the promising application of microspheres modified by zwitterionic polymers in clinical hemoperfusion therapy.