Lysozyme-Immobilized Polyethersulfone Membranes with Satisfactory Hemocompatibility and High Enzyme Activity for Endotoxin Removal

Endotoxinadsorption has received extensive attention in the fieldof blood purification. However, developing highly efficient endotoxinadsorbents with excellent hemocompatibility remains challenging. Inthis study, we propose a new approach for developing the functionalpolyethersulfone (PES) membrane to remove endotoxins. First, the PESpolymer is grafted with polyethylene glycol methyl acrylate (PEG-MA)in a homogeneous phase system via & gamma; irradiation, and PES-g-PEG can be directly used to prepare the membrane by thephase inversion method. Then, polydopamine (PDA) is coated as an adhesivelayer onto a PES-g-PEG membrane in an alkaline aqueoussolution, and lysozyme (Lyz) is covalently immobilized with PDA throughthe Schiff base reaction. Lysozyme acts as an affinity adsorptionligand of endotoxin through charge and hydrophobic action. Our studyreveals that the PEG branched chain and the PDA coating on the PESmembrane can maintain the secondary structure of lysozyme, and thus,the immobilized Lyz can maintain high activity. The adsorption capacityof endotoxins for the PES-g-PEG/PDA/Lyz membraneis 1.28 EU/mg, with an equilibrium adsorption time of 6 h. Therefore,the PES-g-PEG/PDA/Lyz membrane shows great potentialapplication in the treatment of endotoxemia.

Automated summary

In this study, a new approach using a polyethersulfone (PES) membrane grafted with polyethylene glycol methyl acrylate (PEG-MA) was proposed to remove endotoxins. The PES-g-PEG membrane was prepared by phase inversion method after the PES polymer was grafted with PEG-MA via γ irradiation. Polydopamine (PDA) was then coated onto the PES-g-PEG membrane, and lysozyme (Lyz) was immobilized with PDA through a Schiff base reaction. The PES-g-PEG/PDA/Lyz membrane showed high adsorption capacity for endotoxins and has potential application in the treatment of endotoxemia.