Extracorporeal endotoxin removal by novel l-serine grafted PVDF membrane modules

In this work, two sizes of affinity membrane modules for extracorporeal elimination of endotoxin from blood were prepared by grafting l-serine (Ser) ligand onto PVDF hollow fiber membrane. The chemical modification of membrane surface was verified by X-ray photoelectron spectroscopy (XPS) analysis. The modified fiberʹs ability to adsorb endotoxins was examined in aqueous solutions with varied pH value and ionic strength, while the protein adsorption of this fiber was investigated in BSA solution. The small-sized module with 159.4 cm2 effective area was used to remove endotoxin from sepsis patients’ plasma in vitro. As results, when the original concentration was 0.42 EU/ml, the endotoxin adsorption capability was 0.058 EU/cm2 and the removal efficiency was almost 100% for 15 ml, 93.5% and 48.3% for 20 ml and 40 ml samples, respectively. The recovery ratios of total protein and albumin were achieved up to 85.1% and 92.4% correspondingly. The pig model was finally established to evaluate the endotoxin removal efficacy of the scaled up module in direct hemoperfusion. The endotoxin and the inflammation mediator levels decreased after hemoperfusion treatment, indicating the promising potential of this novel adsorber for blood purification of endotoxin.